APBio First 2000
4) In the fractionation of homogenized cells using centrifugation, the primary factor that determines whether a specific cellular component ends up in the supernatant or the pellet
is
7) Which of the following peopleʹs synthesis of this compound from inorganic starting
materials provided evidence against vitalism?
G) Has no effect on phenotype in a
heterozygote
24) Which drawing depicts the electron configuration of nitrogen ( 14
7 N)?
15) Which step shows a split of one molecule into two smaller molecules?
Answer: B
7) at prometaphase of mitosis
Answer: B
9) glycolipid
Answer: B
23) Which drawing depicts the electron configuration of oxygen ( 16
8 O)?
31) How does pyruvate enter the mitochondrion? A) active transport B) diffusion C) facilitated diffusion D) through a channel E) through a pore
Answer: A
56) The process of cellular differentiation is a direct result of A) differential gene expression. B) morphogenesis. C) cell division. D) apoptosis. E) differences in cellular genomes.
Answer: A
44) Which of the steps take place in both mitosis and meiosis? A) 2 B) 3 C) 5 D) 2 and 3 only E) 2, 3, and 5
Answer: B
46) Requires ATP A) light reactions alone B) the Calvin cycle alone C) both the light reactions and the Calvin cycle D) neither the light reactions nor the Calvin cycle E) occurs in the chloroplast but is not part of photosynthesis
Answer: B
52) Which molecule has a carbonyl functional group in the form of an aldehyde?
Answer: B
55) The atomic number of chlorine is 17. The atomic number of magnesium is 12. What is the formula for magnesium chloride? A) MgCl B) MgCl2 C) Mg2Cl D) Mg2Cl2 E) MgCl3
Answer: B
59) Which number represents DNA synthesis? A) I B) II C) III D) IV E) V
Answer: B
60) Which number represents the point in the cell cycle during which the chromosomes are replicated? A) I B) II C) III D) IV E) V
Answer: B
8) A plant has a unique photosynthetic pigment. The leaves of this plant appear to be reddish yellow. What wavelengths of visible light are being absorbed by this pigment? A) red and yellow B) blue and violet C) green and yellow D) blue, green, and red E) green, blue, and yellow
Answer: B
91) Which of the following molecules act as building blocks (monomers) of polypeptides? A) 1, 4, and 6 B) 2, 7, and 8 C) 7, 8, and 13 D) 11, 12, and 13 E) 12, 13, and 15
Answer: B
99) Which of the following molecules consists of a hydrophilic ʺheadʺ region and a hydrophobic ʺtailʺ region? A) 2 B) 5 C) 7 D) 9 E) 11
Answer: B
13) A peptide has the sequence NH 2-phe-pro- lys-gly-phe-pro-COOH . Which of the following sequences in the coding strand of the DNA could code for this peptide? A) 3ʹ UUU-CCC-AAA-GGG-UUU-CCC B) 3ʹ AUG-AAA-GGG-TTT-CCC-AAA-GGG C) 5ʹ TTT-CCC-AAA-GGG-TTT-CCC D) 5ʹ GGG-AAA-TTT-AAA-CCC-ACT-GGG E) 5ʹ ACT-TAC-CAT-AAA-CAT-TAC-UGA
Answer: C
19) A type of protein critical to all cells is organic catalysts called A) feedback activators. B) feedback inhibitors. C) enzymes. D) metabolites. E) nutrients.
Answer: C
28) In one type cross of black × black, the results were as follows: 9/16 black 4/16 yellow 3/16 brown The genotype aabb must result in which of the following? A) Black B) Brown C) Yellow D) A lethal result
Answer: C
34) A given solution contains 0.0001(10 -4 ) moles of hydrogen ions [H + ] per liter. Which of the following best describes this solution? A) acidic: H+ acceptor B) basic: H+ acceptor C) acidic: H+ donor D) basic: H+ donor E) neutral
Answer: C
38) You have in your possession a microscope slide with meiotic cells on it and a light microscope. What would you look for if you wanted to identify metaphase I cells on the slide? A) A visible nuclear envelope B) Separated sister chromatids at each pole of the cell C) Tetrads lined up at the center of the cell D) A synaptonemal complex E) A cleavage furrow
Answer: C
39) If the cells were from a plant, which sample might represent a gametophyte cell? A) I B) II C) III D) Either I or II E) Either II or III
Answer: C
4) If, on average, 46% of the loci in a speciesʹ gene pool are heterozygous, then the average homozygosity of the species should be A) 23% B) 46% C) 54% D) 92% E) There is not enough information to say.
Answer: C
4) Which of the following is a hydrophobic material? A) paper B) table salt C) wax D) sugar E) pasta
Answer: C
42) At which bond would water need to be added to achieve hydrolysis of the peptide, back to its component amino acid?
Answer: C
44) What type of bonding is responsible for maintaining the shape of the tRNA molecule? A) covalent bonding between sulfur atoms B) ionic bonding between phosphates C) hydrogen bonding between base pairs D) van der Waals interactions between hydrogen atoms E) peptide bonding between amino acids
Answer: C
5) We can be sure that a mole of table sugar and a mole of vitamin C are equal in their A) mass in daltons. B) mass in grams. C) number of molecules. D) number of atoms. E) volume.
Answer: C
50) Arrange the following from most general (i.e., most inclusive) to most specific (i.e., least inclusive): 1. Natural selection 2. Microevolution 3. Intrasexual selection 4. Evolution 5. Sexual selection A) 4, 1, 2, 3, 5 B) 4, 2, 1, 3, 5 C) 4, 2, 1, 5, 3 D) 1, 4, 2, 5, 3 E) 1, 2, 4, 5, 3
Answer: C
53) DNA is replicated at this time of the cell cycle: A) G0 B) G1 C) S D) G2 E) M
Answer: C
6) Some bacteria are metabolically active in hot springs because A) they are able to maintain a cooler internal temperature. B) high temperatures make catalysis unnecessary. C) their enzymes have high optimal temperatures. D) their enzymes are completely insensitive to temperature. E) they use molecules other than proteins or RNAs as their main catalysts.
Answer: C
62) What is substance X? A) a coenzyme B) an allosteric inhibitor C) a substrate D) an intermediate E) the product
Answer: C
63) In most cases, differentiation is controlled at which level? A) replication of the DNA B) nucleosome formation C) transcription D) translation E) post- translational activation of the proteins
Answer: C
64) In liver cells, the inner mitochondrial membranes are about 5 X the area of the outer mitochondrial membranes, and about 17 X that of the cellʹs plasma membrane. What purpose must this serve? A) It allows for increased rate of glycolysis. B) It allows for increased rate of the citric acid cycle. C) It increases the surface for oxidative phosphoryation. D) It increases the surface for substrate- level phosphorylation. E) It allows the liver cell to have fewer mitochondria.
Answer: C
8) In a nucleosome, the DNA is wrapped around A) polymerase molecules. B) ribosomes. C) histones. D) a thymine dimer. E) satellite DNA.
Answer: C
88) Which molecule is glycerol? A) 1 B) 6 C) 10 D) 14 E) 15
Answer: C
92) Which of the following molecules is an amino acid with a hydrophobic R group or side chain? A) 3 B) 5 C) 7 D) 8 E) 12
Answer: C
A) Stanley Miller B) Jakob Berzelius C) Friedrich Wohler D) Hermann Kolbe E) August Kekulé
Answer: C
10) Which of the following polymers contain nitrogen? A) starch B) glycogen C) cellulose D) chitin E) amylopectin
Answer: D
15) If the cell whose nuclear material is shown in Figure 12.2 continues toward completion of mitosis, which of the following events would occur next? A) cell membrane synthesis B) spindle fiber formation C) nuclear envelope breakdown D) formation of telophase nuclei E) synthesis of chromatids
Answer: D
16) Why might the cricket genome have 11 times as many base pairs than that of Drosophila melanogaster? A) The two insect species evolved at very different geologic eras. B) Crickets have higher gene density. C) Drosophila are more complex organisms. D) Crickets must have more non -coding DNA. E) Crickets must make many more proteins.
Answer: D
17) Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified? A) as a pentose B) as a hexose C) as a monosaccharide D) as a disaccharide E) as a polysaccharide
Answer: D
23) Assume a thylakoid is somehow punctured so that the interior of the thylakoid is no longer separated from the stroma. This damage will have the most direct effect on which of the following processes? A) the splitting of water B) the absorption of light energy by chlorophyll C) the flow of electrons from photosystem II to photosystem I D) the synthesis of ATP E) the reduction of NADP+
Answer: D
25) Which treatment would you use to determine if the agent is a prion? A) I only B) II only C) III only D) IV only E) either I or IV
Answer: D
35) Which of the following is a map of a chromosome that includes the positions of genes relative to visible chromosomal features, such as stained bands? A) Linkage map B) Physical map C) Recombination map D) Cytogenetic map E) Banded map
Answer: D
37) What is the pH of a solution with a hydrogen ion [H + ] concentration of 10-8 M? A) pH 2 B) pH 4 C) pH 6 D) pH 8 E) pH 10
Answer: D
50) Which of the following would be the same in an enzyme -catalyzed or noncatalyzed reaction? A) a B) b C) c D) d E) e
Answer: D
53) Which molecule contains a carboxyl group?
Answer: D
58) In a linear eukaryotic chromatin sample, which of the following strands is looped into domains by scaffolding? A) DNA without attached histones B) DNA with H1 only C) the 10 nm chromatin fiber D) the 30 nm chromatin fiber E) the metaphase chromosome
Answer: D
60) A cell lacking the ability to make and secrete glycoproteins would most likely be deficient in its A) nuclear DNA. B) extracellular matrix. C) Golgi apparatus. D) B and C only E) A, B, and C
Answer: D
2) Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle? A) CO2 and glucose B) H2O and O2 C) ADP, Pi, and NADP+ D) electrons and H+ E) ATP and NADPH
Answer: E
3) What does transformation involve in bacteria? A) the creation of a strand of DNA from an RNA molecule B) the creation of a strand of RNA from a DNA molecule C) the infection of cells by a phage DNA molecule D) the type of semiconservative replication shown by DNA E) assimilation of external DNA into a cell
Answer: E
3) Which of the following sequences represents the hierarchy of biological organization from the least to the most complex level? A) organelle, tissue, biosphere, ecosystem, population, organism B) cell, community, population, organ system, molecule, organelle C) organism, community, biosphere, molecule, tissue, organ D) ecosystem, cell, population, tissue, organism, organ system E) molecule, cell, organ system, population, ecosystem, biosphere
Answer: E
30) In the F2 generation of the above cross, which of the following phenotypic ratios would be expected? A) 9:3:3:1 B) 9:4:3 C) 1:1:1:1 D) 1:1:1:1:1:1 E) 6:3:3:2:1:1
Answer: E
36) The atomic number of each atom is given to the left of each of the elements below. Which of the atoms has the same valence as carbon ( 12 6 C)? A) 7nitrogen B) 9 flourine C) 10neon D) 12magnesium E) 14silicon
Answer: E
39) Which of the following solutions has the greatest concentration of hydroxyl ions [OH - ]? A) lemon juice at pH 2 B) vinegar at pH 3 C) tomato juice at pH 4 D) urine at pH 6 E) seawater at pH 8
Answer: E
40) Dehydration reactions are used in forming which of the following compounds? A) triacylglycerides B) polysaccharides C) proteins D) A and C only E) A, B, and C
Answer: E
40) In which of the structures are the atoms bonded by ionic bonds? A) A B) B C) C D) C, D, and E only E) none of the structures
Answer: E
41) For each molecule of glucose that is metabolized by glycolysis and the citric acid cycle, what is the total number of NADH + FADH2 molecules produced? A) 4 B) 5 C) 6 D) 10 E) 12
Answer: E
42) In humans, male -pattern baldness is controlled by an autosomal gene that occurs in two allelic forms. Allele Hn determines nonbaldness, and allele Hb determines pattern baldness. In males, because of the presence of testosterone, allele Hb is dominant over Hn . If a man and woman both with genotype HnHb have a son, what is the chance that he will eventually be bald? A) 0% B) 25% C) 33% D) 50% E) 75%
Answer: E
46) A new DNA strand elongates only in the 5ʹ to 3ʹ direction because A) DNA polymerase begins adding nucleotides at the 5ʹ end of the template. B) Okazaki fragments prevent elongation in the 3ʹ to 5ʹ direction. C) the polarity of the DNA molecule prevents addition of nucleotides at the 3ʹ end. D) replication must progress toward the replication fork. E) DNA polymerase can only add nucleotides to the free 3ʹ end.
Answer: E
50) Down syndrome has a frequency in the U.S. population of ~ 1/700 live births. In which of the following groups would you expect this to be significantly higher? A) People in Latin or South America B) The Inuit and other peoples in very cold habitats C) People living in equatorial areas of the world D) Very small population groups E) No groups have such higher frequency
Answer: E
58) What would be an unexpected consequence of changing one amino acid in a protein consisting of 325 amino acids? A) The primary structure of the protein would be changed. B) The tertiary structure of the protein might be changed. C) The biological activity or function of the protein might be altered. D) Only A and C are correct. E) A, B, and C are correct.
Answer: E
58) Which of the following produces the most ATP when glucose (C 6H12O6 ) is completely oxidized to carbon dioxide (CO2 ) and water? A) glycolysis B) fermentation C) oxidation of pyruvate to acetyl CoA D) citric acid cycle E) oxidative phosphorylation (chemiosmosis)
Answer: E
61) Testosterone and estradiol are A) nucleic acids. B) carbohydrates. C) proteins. D) phospholipids. E) steroids.
Answer: E
87) Which of the following molecules contain(s) an aldehyde type of carbonyl functional group? A) 1 B) 4 C) 8 D) 10 E) 1 and 4
Answer: E
9) Which of the following best summarizes the relationship between dehydration reactions and hydrolysis? A) Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers. B) Macromolecular synthesis occurs through the removal of water and digestion occurs through the addition of water. C) Dehydration reactions can occur only after hydrolysis. D) Hydrolysis creates monomers, and dehydration reactions break down polymers. E) A and B are correct.
Answer: E
9) From memory, draw two cells, showing the structures below and any connections between them. nucleus centrosome microtubules
Golgi apparatus
8) How can you tell this cell is undergoing meiosis, not mitosis? Answer: This cell must be undergoing meiosis because homologous chromosomes are
associated with each other; this does not occur in mitosis.
19) Which of the following is true of both starch and cellulose? A) They are both polymers of glucose. B) They are geometric isomers of each other. C) They can both be digested by humans. D) They are both used for energy storage in plants. E) They are both structural components of the plant cell wall.
Answer: A
5) B
11) C
6) G
12) K
2) F
8) A
3) L
9) D
25) Which of the pairs of molecular structures shown below do NOT depict enantiomers (enantiomeric forms) of the same molecule?
A)
8) Construct a table that organizes the following terms, and label the columns and rows. phosphodiester linkages polypeptides monosaccharides peptide bonds triacylglycerols nucleotides glycosidic linkages polynucleotides amino acids ester linkages polysaccharides fatty acids
Answer:
A) carboxyl B) sulfhydryl C) hydroxyl D) amino
Answer: B
56) Which molecule functions to transfer energy between organic molecules?
Answer: D
59) Which molecule is an organic phosphate?
Answer: D
E) Oxygen and electrons
Answer: D
52) This is the shortest part of the cell cycle: A) G0 B) G1 C) S D) G2 E) M
Answer: E
K) A cross between individuals heterozygous for a single
character
15) Flower position, stem length, and seed shape were three characters that Mendel studied. Each is controlled by an independently assorting gene and has dominant and recessive
expression as follows:
C) A cross between an individual with an unknown genotype and a homozygous recessive
individual
33) In an experiment, DNA is allowed to replicate in an environment with all necessary enzymes, dATP, dCTP, dGTP, and radioactively labeled dTTP ( 3H thymidine) for several minutes and then switched to nonradioactive medium. It is then viewed by electron
microscopy and autoradiography. The drawing below represents the results.
66) Which one of the atoms shown would be most likely to form a cation with a charge of +1?
A)
48) Fibroblasts have receptors for this substance on their plasma membranes: A) PDGF B) MPF C) protein kinase D) cyclin E) Cdk
Answer: A
60) Which molecule can function as a base?
Answer: A
61) Roger Kornberg used this method for elucidating the structure of RNA polymerase. A) X- ray crystallography B) bioinformatics C) analysis of amino acid sequence of small fragments D) NMR spectroscopy E) high-speed centrifugation
Answer: A
66) The gene for which protein would most likely be expressed as a result of MyoD activity? A) myosin B) crystallin C) albumin D) hemoglobin E) DNA polymerase
Answer: A
7) fiber of the extracellular matrix
Answer: A
38) Which of the structures is an impossible covalently bonded molecule? A) A B) B C) C D) D E) E
Answer: C
9) Which term describes two centrosomes arranged at opposite poles of the cell? A) telophase B) anaphase C) prometaphase D) metaphase E) prophase
Answer: C
4) Which of the following processes includes all others? A) osmosis B) diffusion of a solute across a membrane C) facilitated diffusion D) passive transport E) transport of an ion down its electrochemical gradient
Answer: D
42) Which is an amino functional group?
Answer: D
57) In the figure above, mitosis is represented by which number? A) I B) II C) III D) IV E) V
Answer: D
15) Several scientific laboratories across the globe are involved in research concerning the origin of life on Earth. Which graph below, if the results were produced abiotically, would have the greatest promise for revealing important information about the origin or Earthʹs first genetic system?
A)
1) A human cell containing 22 autosomes and a Y chromosome is A) a sperm. B) an egg. C) a zygote. D) a somatic cell of a male. E) a somatic cell of a female.
Answer: A
41) Which is a hydroxyl functional group?
Answer: A
64) The MPF protein complex turns itself off by A) activating a process that destroys cyclin component. B) activating an enzyme that stimulates cyclin. C) binding to chromatin. D) exiting the cell. E) activating the anaphase-promoting complex.
Answer: A
29) What kinds of molecules pass through a cell membrane most easily? A) large and hydrophobic B) small and hydrophobic C) large polar D) ionic E) monosaccharides such as glucose
Answer: B
3) An example of a hydrogen bond is the bond between A) C and H in methane (CH 4 ). B) the H of one water molecule and the O of another water molecule. C) Na+and Cl- in salt. D) the two hydrogen atoms in a molecule of hydrogen gas (H 2 ). E) Mg+and Cl- in MgCl2 .
Answer: B
28) You have a freshly -prepared 0.1M solution of glucose in water. Each liter of this solution contains how many glucose molecules? A) 6.02 × 1023 B) 3.01 × 1023 C) 6.02 × 1024 D) 12.04 × 1023 E) 6.02 × 1022
Answer: C
49) What is the most abundant type of RNA? A) mRNA B) tRNA C) rRNA D) pre-mRNA E) hnRNA
Answer: C
62) An enzyme that attaches a phosphate group to another molecule is called a A) phosphatase. B) phosphorylase. C) kinase. D) cyclase. E) ATPase.
Answer: C
8) If ʺxʺ indicates the location of fossils of two closely related species, then fossils of their most-recent common ancestor are most likely to occur in which stratum?
Answer: C
2) The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is A) the oxidation of glucose and other organic compounds. B) the flow of electrons down the electron transport chain. C) the affinity of oxygen for electrons. D) the H+ concentration gradient across the inner mitochondrial membrane. E) the transfer of phosphate to ADP.
Answer: D
2) Viral genomes vary greatly in size and may include from four genes to several hundred genes. Which of the following viral features is most apt to correlate with the size of the genome? A) size of the viral capsomeres B) RNA versus DNA genome C) double versus single strand genomes D) size and shape of the capsid E) glycoproteins of the envelope
Answer: D
2) Which life cycle stage is found in plants but not animals? A) Gamete B) Zygote C) Multicellular diploid D) Multicellular haploid E) Unicellular diploid
Answer: D
32) The flower color trait in radishes is an example of which of the following? A) A multiple allelic system B) Sex linkage C) Codominance D) Incomplete dominance E) Epistasis
Answer: D
34) Based on electron configuration, which of these elements would exhibit chemical behavior most like that of oxygen? A) carbon B) hydrogen C) nitrogen D) sulfur E) phosphorus
Answer: D
40) Transcription factors in eukaryotes usually have DNA binding domains as well as other domains also specific for binding. In general, which of the following would you expect many of them to be able to bind? A) repressors B) ATP C) protein-based hormones D) other transcription factors E) tRNA
Answer: D
46) Which of the following describes the sequence of electron carriers in the electron transport chain, starting with the least electronegative? A) ubiquinone (Q), cytochromes (Cyt), FMN, Fe•S B) cytochromes (Cyt), FMN, ubiquinone, Fe•S C) Fe•S, FMN, cytochromes (Cyt), ubiquinone D) FMN, Fe•S, ubiquinone, cytochromes (Cyt) E) cytochromes (Cyt), Fe•S, ubiquinone, FMN
Answer: D
24) What is it that can be duplicated in a genome? A) DNA sequences above a minimum size only B) DNA sequences below a minimal size only C) entire chromosomes only D) entire sets of chromosomes only E) sequences, chromosomes, or sets of chromosomes
Answer: E
24) Which of these often serve as receptors or cell recognition molecules on cell surfaces? A) transmembrane proteins B) integral proteins C) peripheral proteins D) integrins E) glycoproteins
Answer: E
9) Identify the stage of meiosis shown.
Answer: Metaphase I
HHH
D)
18) Which step involves an endergonic reaction?
Answer: A
43) Of the following human aneuploidies, which is the one that generally has the most severe impact on the health of the individual? A) 47, +21 B) 47, XXY C) 47, XXX D) 47, XYY E) 45, X
Answer: A
44) Cells that are in a nondividing state are in which phase? A) G0 B) G2 C) G1 D) S E) M
Answer: A
13) How do isotopes of the same element differ from each other? A) number of protons B) number of electrons C) number of neutrons D) valence electron distribution E) amount of radioactivity
Answer: C
7) What is the approximate atomic mass of an atom with 16 neutrons, 15 protons, and 15 electrons? A) 15 daltons B) 16 daltons C) 30 daltons D) 31 daltons E) 46 daltons
Answer: D
6) An artificial cell consisting of an aqueous solution enclosed in a selectively permeable membrane is immersed in a beaker containing a different solution. The membrane is permeable to water and to the simple sugars glucose and fructose but impermeable to the
disaccharide sucrose.
36) What is the pH of a solution with a hydroxyl ion [OH - ] concentration of 10-12 M? A) pH 2 B) pH 4 C) pH 10 D) pH 12 E) pH 14
Answer: A
45) Which is a carboxyl functional group?
Answer: C
19) They have a daughter who is a dwarf with normal color vision. What is the probability that she is heterozygous for both genes? A) 0 B) 0.25 C) 0.50 D) 0.75 E) 1.00
Answer: E
20) Substrate- level phosphorylation accounts for approximately what percentage of the ATP formed during glycolysis? A) 0% B) 2% C) 10% D) 38% E) 100%
Answer: E
81) The element nitrogen is present in all of the following except A) proteins. B) nucleic acids. C) amino acids. D) DNA. E) monosaccharides.
Answer: E
9) Which of the following investigators was/were responsible for the following discovery? Phage with labeled proteins or DNA was allowed to infect bacteria. It was shown that the DNA, but not the protein, entered the bacterial cells, and was therefore concluded to be the genetic material. A) Frederick Griffith B) Alfred Hershey and Martha Chase C) Oswald Avery, Maclyn McCarty, and Colin MacLeod D) Erwin Chargaff E) Matthew Meselson and Franklin Stahl
Answer: B
13) Which of these naturalists synthesized a concept of natural selection independently of Darwin? A) Charles Lyell B) Gregor Mendel C) Alfred Wallace D) John Henslow E) Thomas Malthus
Answer: C
5) A man with Klinefelter syndrome (47, XXY) is expected to have any of the following EXCEPT A) lower sperm count. B) possible breast enlargement. C) increased testosterone. D) long limbs. E) female body characteristics.
Answer: C
1) Which of the following properties or processes do we associate with living things? A) evolutionary adaptations B) energy processing C) responding to the environment D) growth and reproduction E) all of the above
Answer: E
52) Discovery science has contributed much to our understanding of nature without most of the steps of the so-called scientific method.
Answer: TRUE
53) Science requires that hypothesis be testable and falsifiable and that observations be repeatable.
Answer: TRUE
69) Which of the following pairs of atoms would be most likely to form an ionic bond?
A)
32) Which free- living cells were the earliest contributors to the formation of Earthʹs oxidizing atmosphere? A) cyanobacteria B) chloroplasts C) mitochondria D) seaweeds E) endosymbionts
Answer: A
43) The results depicted in the graphs above are best accounted for by which of the following facts? A) The Colorado River has been an effective geographic barrier to these two types of squirrels for several million years. B) There is more white fur on the tails of the northern squirrels than on the tails of the southern squirrels. C) Both types of squirrel subsist largely on a diet of pine nuts and juniper seeds in this ecosystem. D) Both types of squirrel share the same common ancestor. E) Both types of squirrel are active during the day.
Answer: A
43) Where do the enzymatic reactions of the Calvin cycle take place? A) stroma of the chloroplast B) thylakoid membranes C) outer membrane of the chloroplast D) electron transport chain E) thylakoid space
Answer: A
55) Nerve and muscle cells are in this phase: A) G0 B) G1 C) S D) G2 E) M
Answer: A
63) The molecule shown here could be described in chemical symbols as A) CH4 . B) H2O. C) C2H3 . D) C4H4 . E) CH2O.
Answer: A
7) What was the species concept most used by Linnaeus? A) biological B) morphological C) ecological D) phylogenetic
Answer: B
77) The ATP made during fermentation is generated by which of the following? A) the electron transport chain B) substrate- level phosphorylation C) chemiosmosis D) oxidative phosphorylation E) aerobic respiration
Answer: B
29) The general name for an enzyme that transfers phosphate groups from ATP to a protein is A) phosphorylase. B) phosphatase. C) protein kinase. D) ATPase. E) protease.
Answer: C
30) Shared derived characters are most likely to be found in taxa that are A) paraphyletic. B) polyphyletic. C) monophyletic.
Answer: C
35) Which of the following is (are) true of snRNPs? A) They are made up of both DNA and RNA. B) They bind to splice sites at each end of the exon. C) They join together to form a large structure called the spliceosome. D) They act only in the cytosol. E) They attach introns to exons in the correct order.
Answer: C
40) Which curve represents the behavior of an enzyme taken from a bacterium that lives in hot springs at temperatures of 70°C or higher? A) curve 1 B) curve 2 C) curve 3 D) curve 4 E) curve 5
Answer: C
47) The frequency of Down syndrome in the human population is most closely correlated with which of the following? A) Frequency of new meiosis B) Average of the ages of mother and father C) Age of the mother D) Age of the father E) Exposure of pregnant women to environmental pollutants
Answer: C
55) What is the voltage across a membrane called? A) water potential B) chemical gradient C) membrane potential D) osmotic potential E) electrochemical gradient
Answer: C
30) In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele a is 0.1. What is the percentage of the population that is heterozygous for this allele? A) 90 B) 81 C) 49 D) 18 E) 10
Answer: D
42) One liter of a solution of pH 2 has how many more hydrogen ions (H + ) than 1 L of a solution of pH 6? A) 4 times more B) 400 times more C) 4,000 times more D) 10,000 times more E) 100,000 times more
Answer: D
51) The structure depicted in Figure 5.7 shows the A) 1-4 linkage of the α glucose monomers of starch. B) 1-4 linkage of the β glucose monomers of cellulose. C) double helical structure of a DNA molecule. D) α helix secondary structure of a polypeptide. E) β pleated sheet secondary structure of a polypeptide.
Answer: D
65) In the methane molecule shown here, bonds have formed that include both the s orbital valence electrons of the hydrogen atoms and the p orbital valence electrons of the carbon. The electrons in these bonds are said to have A) double orbitals. B) tetrahedral orbitals. C) complex orbitals. D) hybrid orbitals. E) reduced orbitals.
Answer: D
68) Cattle breeders have improved the quality of meat over the years by which process? A) artificial selection B) directional selection C) stabilizing selection D) A and B E) A and C
Answer: D
A) Stanley Miller B) Jakob Berzelius C) Friedrich Wohler D) Hermann Kolbe E) August Kekulé
Answer: D
28) How many separate species, both extant and extinct, are depicted in this tree? A) 2 B) 3 C) 4 D) 5 E) 6
Answer: E
6) Which of these is the smallest unit upon which natural selection directly acts? A) a speciesʹ gene frequency B) a populationʹs gene frequency C) an individualʹs genome D) an individualʹs genotype E) an individualʹs phenotype
Answer: E
7) Although quite different in structure, plants and animals share some basic similarities in their development, such as A) the importance of cell and tissue movements. B) the importance of selective cell enlargement. C) the importance of homeobox -containing homeotic genes. D) a common evolutionary origin of the complete developmental program. E) a cascade of transcription factors that regulate gene expression on a finer and finer scale.
Answer: E
13) Two pea plants heterozygous for the characters of pod color and pod shape are crossed. Draw a Punnett square to determine the phenotypic ratios of the offspring.
Answer:
9) Draw the polynucleotide strand in Figure 5.27a from your textbook, and label the bases G, T, C, and T, starting from the 5ʹ end. Now, draw the complementary strand of the double helix, using the same symbols for phosphates (circles), sugars (pentagons), and bases. Label the bases. Draw arrows showing the 5ʹ → 3ʹ direction of each strand. Use the arrows to make sure the second strand is antiparallel to the first. Hint: After you draw the first strand vertically, turn the paper upside down; it is easier to draw the second strand from the 5ʹ toward the 3ʹ direction as you go from top to bottom.
Answer:
1) What does the operon model attempt to explain? A) the coordinated control of gene expression in bacteria B) bacterial resistance to antibiotics C) how genes move between homologous regions of DNA D) the mechanism of viral attachment to a host cell E) horizontal transmission of plant viruses
Answer: A
10) Based on the above table, which virus meets the requirements for a bacteriophage?
Answer: A
14) Which of the plants will be true -breeding? A) 1 and 4 B) 2 and 3 C) 1—4 D) 1 only E) None
Answer: A
44) Which bond is closest to the N- terminus of the molecule?
Answer: A
46) The application of scientific knowledge for some specific purpose is known as A) technology. B) deductive science. C) inductive science. D) anthropologic science. E) pure science.
Answer: A
48) Which molecule is water soluble because it has a hydroxyl functional group?
Answer: A
49) Which molecule is an alcohol?
Answer: A
27) Which drawing depicts an atom with a valence of 3?
Answer: B
27) Which of the following represents a difference between viruses and viroids? A) Viruses infect many types of cells, whereas viroids infect only prokaryotic cells. B) Viruses have capsids composed of protein, whereas viroids have no capsids. C) Viruses contain introns; viroids have only exons. D) Viruses always have genomes composed of DNA, whereas viroids always have genomes composed of RNA. E) Viruses cannot pass through plasmodesmata; viroids can.
Answer: B
3) In mechanism, photophosphorylation is most similar to A) substrate- level phosphorylation in glycolysis. B) oxidative phosphorylation in cellular respiration. C) the Calvin cycle. D) carbon fixation. E) reduction of NADP+ .
Answer: B
39) The method of scientific inquiry that describes natural structures and processes as accurately as possible through careful observation and the analysis of data is known as A) hypothesis-based science. B) discovery science. C) experimental science. D) quantitative science. E) qualitative science.
Answer: B
40) What is the maximum number of electrons in a 2 p orbital of an atom? A) 1 B) 2 C) 3 D) 4 E) 5
Answer: B
5) Sparrows with average-sized wings survive severe storms better than those with longer or shorter wings, illustrating A) the bottleneck effect. B) stabilizing selection. C) frequency-dependent selection. D) neutral variation. E) disruptive selection.
Answer: B
53) Which of the following represents the activation energy required for the enzyme -catalyzed reaction? A) a B) b C) c D) d E) e
Answer: B
58) Which molecule is a thiol?
Answer: B
70) Which of the following are nitrogenous bases of the pyrimidine type? A) guanine and adenine B) cytosine and uracil C) thymine and guanine D) ribose and deoxyribose E) adenine and thymine
Answer: B
82) Which of the following is a diverse group of hydrophobic molecules? A) carbohydrates B) lipids C) proteins D) nucleic acids
Answer: B
18) In an analysis of the nucleotide composition of DNA, which of the following will be found? A) A = C B) A = G and C = T C) A + C = G + T D) G + C = T + A
Answer: C
22) A defining characteristic of allopatric speciation is A) the appearance of new species in the midst of old ones. B) asexually reproducing populations. C) geographic isolation. D) artificial selection. E) large populations.
Answer: C
24) Which of the following is most similar in structure to ATP? A) an anabolic steroid B) a DNA helix C) an RNA nucleotide D) an amino acid with three phosphate groups attached E) a phospholipid
Answer: C
32) How many neutrons are present in the nucleus of a phosphorus atom? A) 8 B) 15 C) 16 D) 31 E) 46
Answer: C
43) Which bond is a peptide bond?
Answer: C
47) Which is a general term for enzymes that activate or inactivate other proteins by phosphorylating them? A) PDGF B) MPF C) protein kinase D) cyclin E) Cdk
Answer: C
7) Which of the following is the correct sequence of these events in the origin of life? I. formation of protobionts II. synthesis of organic monomers III. synthesis of organic polymers IV. formation of DNA-based genetic systems A) I, II, III, IV B) I, III, II, IV C) II, III, I, IV D) IV, III, I, II E) III, II, I, IV
Answer: C
75) Which of the following statements best summarizes the structural differences between DNA and RNA? A) RNA is a protein, whereas DNA is a nucleic acid. B) DNA is a protein, whereas RNA is a nucleic acid. C) DNA nucleotides contain a different sugar than RNA nucleotides. D) RNA is a double helix, but DNA is single-stranded. E) A and D are correct.
Answer: C
8) How many molecules of water are needed to completely hydrolyze a polymer that is 11 monomers long? A) 12 B) 11 C) 10 D) 9 E) 8
Answer: C
14) Why are carbohydrates and fats considered high energy foods? A) They have a lot of oxygen atoms. B) They have no nitrogen in their makeup. C) They can have very long carbon skeletons. D) They have a lot of electrons associated with hydrogen. E) They are easily reduced.
Answer: D
2) Which of the following hydrocarbons has a double bond in its carbon skeleton? A) C3H8 B) C2H6 C) CH4 D) C2H4 E) C2H2
Answer: D
26) In a plant cell, where are the ATP synthase complexes located? A) thylakoid membrane B) plasma membrane C) inner mitochondrial membrane D) A and C E) A, B, and C
Answer: D
27) When chemical, transport, or mechanical work is done by an organism, what happens to the heat generated? A) It is used to power yet more cellular work. B) It is used to store energy as more ATP. C) It is used to generate ADP from nucleotide precursors. D) It is lost to the environment. E) It is transported to specific organs such as the brain.
Answer: D
32) Once transcribed, eukaryotic mRNA typically undergoes substantial alteration that includes A) union with ribosomes. B) fusion into circular forms known as plasmids. C) linkage to histone molecules. D) excision of introns. E) fusion with other newly transcribed mRNA.
Answer: D
86) Which of the following combinations could be linked together to form a nucleotide? A) 1, 2, and 11 B) 3, 7, and 8 C) 5, 9, and 10 D) 11, 12, and 13 E) 12, 14, and 15
Answer: D
19) Which measurement would help determine absolute dates by radiometric means? A) the accumulation of the daughter isotope B) the loss of parent isotopes C) the loss of daughter isotopes D) all three of these E) only A and B
Answer: E
24) Approximately what proportion of the DNA in the human genome codes for proteins or functional RNA? A) 83% B) 46% C) 32% D) 13% E) 1.5%
Answer: E
32) Which of the five common ancestors, labeled V—Z, has been most successful in terms of the percent of its derived species that are extant? A) V B) W C) X D) Y E) Z
Answer: E
59) Altering which of the following levels of structural organization could change the function of a protein? A) primary B) secondary C) tertiary D) quaternary E) all of the above
Answer: E
6) cholesterol
Answer: E
76) When imbalances occur in the sex ratio of sexual species that have two sexes (i.e., other than a 50:50 ratio), the members of the minority sex often receive a greater proportion of care and resources from parents than do the offspring of the majority sex. This is most clearly an example of A) sexual selection. B) disruptive selection. C) balancing selection. D) stabilizing selection. E) frequency-dependent selection.
Answer: E
89) Which molecule is a saturated fatty acid? A) 1 B) 5 C) 6 D) 8 E) 9
Answer: E
49) Recent evidence points to the conclusion that the ancestral finches of the Galapagos originated in the islands of the Caribbean.
Answer: TRUE
68) The accompanying figure shows the electron transport chain. Which of the following is the combination of substances that is initially added to the chain? A) oxygen, carbon dioxide, and water B) NAD+ , FAD, and electrons C) NADH, FADH2 , and protons D) NADH, FADH2 , and electrons
190 Chapter 9, Cellular Respiration: Harvesting Chemical Energy
1) J
7) E
9) Draw three water molecules and label the atoms. Draw solid lines to indicate covalent bonds and dotted lines for hydrogen bonds. Add partial charge labels as appropriate.
Answer:
12) The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are the α form. Which of the following could amylase break down? A) glycogen B) cellulose C) chitin D) A and B only E) A, B, and C
Answer: A
15) If 2 molecules of the general type shown in Figure 5.1 were linked together, carbon 1 of one molecule to carbon 4 of the other, the single molecule that would result would be A) maltose. B) fructose. C) glucose. D) galactose. E) sucrose.
Answer: A
16) What kind of chemical bond is found between paired bases of the DNA double helix? A) hydrogen B) ionic C) covalent D) sulfhydryl E) phosphate
Answer: A
29) Which of the following contains hydrolytic enzymes? A) lysosome B) vacuole C) mitochondrion D) Golgi apparatus E) peroxisome
Answer: A
45) Produces molecular oxygen (O 2 ) A) light reactions alone B) the Calvin cycle alone C) both the light reactions and the Calvin cycle D) neither the light reactions nor the Calvin cycle E) occurs in the chloroplast but is not part of photosynthesis
Answer: A
5) The final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is A) oxygen. B) water. C) NAD+ . D) pyruvate. E) ADP.
Answer: A
52) Which of the following possesses a microtubular structure similar to a basal body? A) centriole B) lysosome C) nucleolus D) peroxisome E) ribosome
Answer: A
58) G1 is represented by which number(s)? A) I and V B) II and IV C) III D) IV E) V
Answer: A
6) Which of the following is not a polymer? A) glucose B) starch C) cellulose D) chitin E) DNA
Answer: A
67) The general process that leads to the differentiation of cells is called A) determination. B) specialization. C) identification. D) differentialization. E) cellularization.
Answer: A
74) Which of the following normally occurs whether or not oxygen (O2 ) is present? A) glycolysis B) fermentation C) oxidation of pyruvate to acetyl CoA D) citric acid cycle E) oxidative phosphorylation (chemiosmosis)
Answer: A
2) Early 19th-century scientists believed that living organisms differed from nonliving things as a result of possessing a ʺlife forceʺ that could create organic molecules from inorganic matter. The term given to this belief is A) organic synthesis. B) vitalism. C) mechanism. D) organic evolution. E) inorganic synthesis.
Answer: B
23) A molecule with the formula C18H36O2 is probably a A) carbohydrate. B) fatty acid. C) protein. D) nucleic acid. E) hydrocarbon.
Answer: B
26) Which of the following numbers represents a polyphyletic taxon? A) 2 B) 3 C) 4 D) 5 E) more than one of these
Answer: B
34) The most likely explanation for the recent decline in cichlid species diversity in Lake Victoria is A) reinforcement. B) fusion. C) stability. D) geographic isolation. E) polyploidy.
Answer: B
41) Which sample might represent an animal cell in G 2 phase of the cell cycle? A) I B) II C) III D) Both I and II E) Both II and III
Answer: B
47) What results from an unequal sharing of electrons between atoms? A) a nonpolar covalent bond B) a polar covalent bond C) an ionic bond D) a hydrogen bond E) a hydrophobic interaction
Answer: B
63) Substance A functions as A) a coenzyme. B) an allosteric inhibitor. C) the substrate. D) an intermediate. E) a competitive inhibitor.
Answer: B
76) Gap genes and pair-rule genes fall into this category: A) homeotic genes B) segmentation genes C) egg-polarity genes D) morphogens E) inducers
Answer: B
9) A small molecule that specifically binds to another molecule, usually a larger one A) is called a signal transducer. B) is called a ligand. C) is called a polymer. D) seldom is involved in hormonal signaling. E) usually terminates a signal reception.
Answer: B
9) At which stage of mitosis are chromosomes usually photographed in the preparation of a karyotype? A) Prophase B) Metaphase C) Anaphase D) Telophase E) Interphase
Answer: B
90) In colorectal cancer, several genes must be mutated in order to make a cell a cancer cell, supporting Knudsenʹs hypothesis. Which of the following kinds of genes would you expect to be mutated? A) genes coding for enzymes that act in the colon B) genes involved in control of the cell cycle C) genes that are especially susceptible to mutation D) the same genes that Knudsen identified as associated with retinoblastoma E) the genes of the bacteria that are abundant in the colon
Answer: B
A) allopatric speciation, ecological isolation B) sympatric speciation, habitat differentiation C) allopatric speciation, behavioral isolation D) sympatric speciation, sexual selection E) sympatric speciation, allopolyploidy
Answer: B
11) When crossing an organism that is homozygous recessive for a single trait with a heterozygote, what is the chance of producing an offspring with the homozygous recessive phenotype? A) 0% B) 25% C) 50% D) 75% E) 100%
Answer: C
15) Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules? A) lipids B) starches C) proteins D) steroids E) glucose
Answer: C
25) What term is used to describe the transfer of free energy from catabolic pathways to anabolic pathways? A) feedback regulation B) bioenergetics C) energy coupling D) entropy E) cooperativity
Answer: C
34) Generation of proton gradients across membranes occurs during A) photosynthesis. B) respiration. C) both photosynthesis and respiration. D) neither photosynthesis nor respiration. E) photorespiration.
Answer: C
36) Skin color in a certain species of fish is inherited via a single gene with four different alleles. How many different types of gametes would be possible in this system? A) 1 B) 2 C) 4 D) 8 E) 16
Answer: C
18) Shown here in Figure 4.2 are the structures of glucose and fructose. These two molecules are A) geometric isotopes. B) enantiomers. C) geometric isomers. D) structural isomers. E) nonisotopic isomers.
Answer: D
2) Which of the following is a correct sequence of levels in lifeʹs hierarchy, proceeding downward from an individual animal? A) brain, organ system, nerve cell, nervous tissue B) organ system, nervous tissue, brain C) organism, organ system, tissue, cell, organ D) nervous system, brain, nervous tissue, nerve cell E) organ system, tissue, molecule, cell
Answer: D
37) A biologist ground up some plant leaf cells and then centrifuged the mixture to fractionate the organelles. Organelles in one of the heavier fractions could produce ATP in the light, while organelles in the lighter fraction could produce ATP in the dark. The heavier and lighter fractions are most likely to contain, respectively, A) mitochondria and chloroplasts. B) chloroplasts and peroxisomes. C) peroxisomes and chloroplasts. D) chloroplasts and mitochondria. E) mitochondria and peroxisomes.
Answer: D
49) Research indicates that acid precipitation can damage living organisms by A) buffering aquatic systems such as lakes and streams. B) decreasing the H + concentration of lakes and streams. C) increasing the OH- concentration of lakes and streams. D) washing away certain mineral ions that help buffer soil solution and are essential nutrients for plant growth. E) both B and C
Answer: D
5) Asexual reproduction results in identical offspring unless which of the following occurs? A) Natural selection B) Cloning C) Crossing over D) Mutation E) Environmental change
Answer: D
5) peripheral protein
Answer: D
51) Which would you expect of a eukaryotic cell lacking telomerase? A) a high probability of becoming cancerous B) production of Okazaki fragments C) inability to repair thymine dimers D) a reduction in chromosome length E) high sensitivity to sunlight
Answer: D
56) Which molecule(s) of the Calvin cycle is/are most like molecules found in glycolysis? A) A, B, C, and E B) B, C, and E C) A only D) C and D only E) E only
Answer: D
7) Two plants are crossed, resulting in offspring with a 3:1 ratio for a particular trait. This suggests A) that the parents were true-breeding for contrasting traits. B) incomplete dominance. C) that a blending of traits has occurred. D) that the parents were both heterozygous. E) that each offspring has the same alleles.
Answer: D
8) Which of these evolutionary agents is most consistent at causing populations to become better suited to their environments over the course of generations? A) Mutation B) Non-random mating C) Gene flow D) Natural selection E) Genetic drift
Answer: D
2) Which of the following has the largest genome and the fewest genes per million base pairs? A) Haemophilus influenzae (bacterium) B) Saccharomyces cerevisiae (yeast) C) Arabidopsis thaliana (plant) D) Drosophila melanogaster (fruit fly) E) Homo sapiens (human)
Answer: E
28) Why is glycolysis described as having an investment phase and a payoff phase? A) It both splits molecules and assembles molecules. B) It attaches and detaches phosphate groups. C) It uses glucose and generates pyruvate. D) It shifts molecules from cytosol to mitochondrion. E) It uses stored ATP and then forms a net increase in ATP.
Answer: E
30) A filamentous organism has been isolated from decomposing organic matter. This organism has a cell wall but no chloroplasts. How would you classify this organism? A) domain Bacteria, kingdom Prokaryota B) domain Archaea, kingdom Bacteria C) domain Eukarya, kingdom Plantae D) domain Eukarya, kingdom Protista E) domain Eukarya, kingdom Fungi
Answer: E
42) Which of the following synthesizes short segments of RNA? A) helicase B) DNA polymerase III C) ligase D) DNA polymerase I E) primase
Answer: E
42) Which of these is based on a deduction? A) My car wonʹt start. B) My carʹs battery is dead. C) My car is out of gas. D) I lost my car key. E) If I turn the key in the ignition while stepping on the gas pedal, then my car will start.
Answer: E
47) During aerobic respiration, which of the following directly donates electrons to the electron transport chain at the lowest energy level? A) NAD+ B) NADH C) ATP D) ADP + Pi E) FADH2
Answer: E
87) Which of the following can contribute to the development of cancer? A) random spontaneous mutations B) mutations caused by X-rays C) transposition D) chromosome translocations E) all of the above
Answer: E
30) In mice, black color (B) is dominant to white ( b). At a different locus, a dominant allele ( A) produces a band of yellow just below the tip of each hair in mice with black fur. This gives a frosted appearance known as agouti. Expression of the recessive allele ( a) results in a solid coat color. If mice that are heterozygous at both loci are crossed, what is the expected phenotypic ratio of their offspring? Answer: 9 B_A_ (agouti) : 3 B_aa (black) : 3 bbA_ (white) : 1 bbaa (white). Overall, 9 agouti : 3
black : 4 white.
1) For a couple of decades, biologists knew the nucleus contained DNA and proteins. The prevailing opinion was that the genetic material was proteins, and not DNA. The reason for this belief was that proteins are more complex than DNA. What was the basis of this thinking? A) Proteins have a greater variety of three -dimensional forms than does DNA. B) Proteins have two different levels of structural organization; DNA has four. C) Proteins are made of 40 amino acids and DNA is made of four nucleotides. D) Some viruses only transmit proteins. E) A and B are correct.
Answer: A
10) The organization of organisms has become increasingly complex with time. This statement A) is consistent with the second law of thermodynamics. B) requires that due to evolution, the entropy of the universe increased. C) is based on the fact that organisms function as closed systems. D) A and B only E) A, B, and C
Answer: A
46) Of the following, which cell structure would most likely be visible with a light microscope that has been manufactured to the maximum resolving power possible? A) mitochondrion B) microtubule C) ribosome D) largest microfilament E) nuclear pore
Answer: A
47) Which line represents the bag with the highest initial concentration of sucrose?
Answer: A
55) In humans, the embryonic and fetal forms of hemoglobin have a higher affinity for oxygen than that of adults. This is due to A) nonidentical genes that produce different versions of globins during development. B) identical genes that generate many copies of the ribosomes needed for fetal globin production. C) pseudogenes, which interfere with gene expression in adults. D) the attachment of methyl groups to cytosine following birth, which changes the type of hemoglobin produced. E) histone proteins changing shape during embryonic development.
Answer: A
60) One possible use of transgenic plants is in the production of human proteins, such as vaccines. Which of the following is a possible hindrance that must be overcome? A) prevention of transmission of plant allergens to the vaccine recipients B) prevention of vaccine-containing plants being consumed by insects C) use of plant cells to translate non-plant derived mRNA D) inability of the human digestive system to accept plant -derived protein E) the need to cook all such plants before consuming them
Answer: A
62) When a disease is said to have a multifactorial basis, it means that A) both genetic and environmental factors contribute to the disease. B) it is caused by a gene with a large number of alleles. C) it affects a large number of people. D) it has many different symptoms. E) it tends to skip a generation.
Answer: A
7) Most human - infecting viruses are maintained in the human population only. However, a zoonosis is a disease that is transmitted from other vertebrates to humans, at least sporadically, without requiring viral mutation. Which of the following is the best example of a zoonosis? A) rabies B) herpesvirus C) smallpox D) HIV E) hepatitis virus
Answer: A
7) The spontaneous loss of amino groups from adenine results in hypoxanthine, an uncommon base, opposite thymine in DNA. What combination of molecules could repair such damage? A) nuclease, DNA polymerase, DNA ligase B) telomerase, primase, DNA polymerase C) telomerase, helicase, single-strand binding protein D) DNA ligase, replication fork proteins, adenylyl cyclase E) nuclease, telomerase, primase
Answer: A
A) Stanley Miller B) Jakob Berzelius C) Friedrich Wohler D) Hermann Kolbe E) August Kekulé
Answer: A
12) The illustration above represents A) a computer simulation of the structure of a eukaryotic cell. B) a map of a network of protein interactions within a eukaryotic cell. C) an inventory of all the genes in a fruit fly. D) an X-ray diffraction image of the nucleus and cytoplasm of a eukaryotic cell. E) a computer generated map of the interaction of genes and cytoplasm in a prokaryotic cell.
Answer: B
12) Which process in eukaryotic cells will proceed normally whether oxygen (O 2 ) is present or absent? A) electron transport B) glycolysis C) the citric acid cycle D) oxidative phosphorylation E) chemiosmosis
Answer: B
17) Which of the following is reflective of the phrase ʺthe whole is greater than the sum of its partsʺ? A) high- throughput technology B) emergent properties C) natural selection D) reductionism E) feedback regulations
Answer: B
20) Where do the microtubules of the spindle originate during mitosis in both plant and animal cells? A) centromere B) centrosome C) centriole D) chromatid E) kinetochore
Answer: B
4) Sturtevant provided genetic evidence for the existence of four pairs of chromosomes in Drosophila in which of these ways? A) There are four major functional classes of genes in Drosophila. B) Drosophila genes cluster into four distinct groups of linked genes. C) The overall number of genes in Drosophila is a multiple of four. D) The entire Drosophila genome has approximately 400 map units. E) Drosophila genes have, on average, four different alleles.
Answer: B
8) If proteins were composed of only 12 different kinds of amino acids, what would be the smallest possible codon size in a genetic system with four different nucleotides? A) 1 B) 2 C) 3 D) 4 E) 12
Answer: B
12) A carbon atom is most likely to form what kind of bond(s) with other atoms? A) ionic B) hydrogen C) covalent D) A and B only E) A, B, and C
Answer: C
28) Which drawing depicts an atom with a valence of 2?
Answer: C
34) An inhibitor of phosphodiesterase activity would have which of the following effects? A) block the response of epinephrine B) decrease the amount of cAMP in the cytoplasm C) block the activation of G proteins in response to epinephrine binding to its receptor D) prolong the effect of epinephrine by maintaining elevated cAMP levels in the cytoplasm E) block the activation of protein kinase A
Answer: D
40) Which of the following is a function of those spindle microtubules that do not attach to kinetochores? A) maintaining an appropriate spacing among the moving chromosomes B) producing a cleavage furrow when telophase is complete C) providing the ATP needed by the fibers attached to kinetochores D) maintaining the region of overlap of fibers in the cellʹs center E) pulling the poles of the spindles closer to one another
Answer: D
44) Which of Lystrosaurusʹ features help explain why these organisms fossilized so abundantly? I. the presence of hard parts, such as tusks II. its herbivorous diet III. its persistence across at least two geological eras IV. its widespread geographic distribution V. its mixture of reptilian and mammalian features A) I and III B) III and V C) III and V D) I, III, and IV E) II, III, IV, and V
Answer: D
5) What gives rise to the cohesiveness of water molecules? A) hydrophobic interactions B) nonpolar covalent bonds C) ionic bonds D) hydrogen bonds E) both A and C
Answer: D
57) Misfolding of polypeptides is a serious problem in cells. Which of the following diseases are associated with an accumulation of misfolded proteins? A) Alzheimerʹs B) Parkinsonʹs C) diabetes D) A and B only E) A, B, and C
Answer: D
8) Apoptosis involves all but the following: A) fragmentation of the DNA B) cell-signaling pathways C) activation of cellular enzymes D) lysis of the cell E) digestion of cellular contents by scavenger cells
Answer: D
41) Which population is most likely to be subject to the bottleneck effect? A) Population A. B) Population B. C) Population C. D) They are all the same. E) It is impossible to tell from the information given.
Answer: A
33) The somatic cells derived from a single -celled zygote divide by which process? A) meiosis B) mitosis C) replication D) cytokinesis alone E) binary fission
Answer: B
20) Generally, within a lineage, the largest number of shared derived characters should be found among two organisms that are members of the same A) kingdom. B) class. C) domain. D) family. E) order.
Answer: D
49) Which of the following molecules contains the strongest polar covalent bond? A) H2 B) O2 C) CO2 D) H2O E) CH4
Answer: D
D) Having two identical alleles for
a gene
I) Having two different alleles for
a gene
9) Which of the following peopleʹs synthesis of this compound from inorganic starting
materials provided evidence against vitalism?
21) RNA polymerase moves in which direction along the DNA? A) 3ʹ → 5ʹ along the template strand B) 3ʹ → 5ʹ along the coding (sense) strand C) 5ʹ → 3ʹ along the template strand D) 3ʹ → 5ʹ along the coding strand E) 5ʹ → 3ʹ along the double-stranded DNA
Answer: A
26) In both eukaryotes and prokaryotes, gene expression is primarily regulated at the level of A) transcription. B) translation. C) mRNA stability. D) mRNA splicing. E) protein stability.
Answer: A
26) Which of the following cuts DNA molecules at specific locations? A) restriction enzymes B) gene cloning C) DNA ligase D) gel electrophoresis E) reverse transcriptase
Answer: A
32) RFLP analysis can be used to distinguish between alleles based on differences in which of the following? A) restriction enzyme recognition sites between the alleles B) the amount of DNA amplified from the alleles during PCR C) the ability of the alleles to be replicated in bacterial cells D) the proteins expressed from the alleles E) the ability of nucleic acid probes to hybridize to the alleles
Answer: A
41) A researcher has used in vitro mutagenesis to mutate a cloned gene and then has reinserted this into a cell. In order to have the mutated sequence disable the function of the gene, what must then occur? A) recombination resulting in replacement of the wild type with the mutated gene B) use of a microarray to verify continued expression of the original gene C) replication of the cloned gene using a bacterial plasmid D) transcription of the cloned gene using a BAC E) attachment of the mutated gene to an existing mRNA to be translated
Answer: A
35) What is the relationship between wavelength of light and the quantity of energy per photon? A) They have a direct, linear relationship. B) They are inversely related. C) They are logarithmically related. D) They are separate phenomena. E) They are only related in certain parts of the spectrum.
Answer: B
73) A double-stranded DNA molecule contains a total of 120 purines and 120 pyrimidines. This DNA molecule could be composed of A) 120 adenine and 120 uracil molecules. B) 120 thymine and 120 adenine molecules. C) 120 cytosine and 120 thymine molecules. D) 240 adenine and 240 cytosine molecules. E) 240 guanine and 240 thymine molecules.
Answer: B
13) Which of the following seems to be the known upper and lower size limits of genomes? A) 1—2900 Mb (million base pairs) B) 1,500—40,000 Mb C) 1—580,000 Mb D) 100—120,000 Mb E) 100—200,000 Mb
Answer: C
18) A student wishes to clone a sequence of DNA of ~200 kb. Which vector would be appropriate? A) a plasmid B) a typical bacteriophage C) a BAC D) a plant virus E) a large polypeptide
Answer: C
2) A slice of pizza has 500 kcal. If we could burn the pizza and use all the heat to warm a 50 -L container of cold water, what would be the approximate increase in the temperature of the water? (Note: A liter of cold water weighs about 1 kg.) A) 50°C B) 5°C C) 10°C D) 100°C E) 1°C
Answer: C
2) Trace elements are those required by an organism in only minute quantities. Which of the following is a trace element that is required by humans and other vertebrates? A) nitrogen B) calcium C) iodine D) sodium E) phosphorus
Answer: C
23) Which branch of biology is concerned with the naming and classifying of organisms? A) informatics B) schematic biology C) taxonomy D) genomics E) evolution
Answer: C
32) This binds to a site in the DNA far from the promoter to stimulate transcription: A) enhancer B) promoter C) activator D) repressor E) terminator
Answer: C
5) A mutation in this section of DNA could influence the binding of RNA polymerase to the DNA: A) operon B) inducer C) promoter D) repressor E) corepressor
Answer: C
7) Which of the following does not occur during the Calvin cycle? A) carbon fixation B) oxidation of NADPH C) release of oxygen D) regeneration of the CO2 acceptor E) consumption of ATP
Answer: C
19) The best conclusion concerning delta is that the cells A) contain no DNA. B) contain no RNA. C) contain only one chromosome that is very short. D) are actually in the G0 phase. E) divide in the G1 phase.
Answer: D
37) If a young male child has cystic fibrosis, which of the following would affect his fertility? A) inability to make sperm B) incomplete maturation of the testes C) failure to form genital structures appropriately D) incorrect concentrations of ions in semen E) abnormal pH in seminal fluid
Answer: D
46) When two atoms are equally electronegative, they will interact to form A) equal numbers of isotopes. B) ions. C) polar covalent bonds. D) nonpolar covalent bonds. E) ionic bonds.
Answer: D
68) Some enzymatic regulation is allosteric. In such cases, which of the following would usually be found? A) cooperativity B) feedback inhibition C) both activating and inhibitory activity D) an enzyme with more than one subunit E) the need for cofactors
Answer: D
90) Which of the following molecules is a purine type of nitrogenous base? A) 2 B) 3 C) 5 D) 12 E) 13
Answer: E
14) Which of the following can be determined directly from X -ray diffraction photographs of crystallized DNA? A) the diameter of the helix B) the rate of replication C) the sequence of nucleotides D) the bond angles of the subunits E) the frequency of A vs. T nucleotides
Answer: A
29) What are prions? A) misfolded versions of normal brain protein B) tiny molecules of RNA that infect plants C) viral DNA that has had to attach itself to the host genome D) viruses that invade bacteria E) a mobile segment of DNA
Answer: A
29) Where are the molecules of the electron transport chain found in plant cells? A) thylakoid membranes of chloroplasts B) stroma of chloroplasts C) inner membrane of mitochondria D) matrix of mitochondria E) cytoplasm
Answer: A
3) The anticodon of a particular tRNA molecule is A) complementary to the corresponding mRNA codon. B) complementary to the corresponding triplet in rRNA. C) the part of tRNA that bonds to a specific amino acid. D) changeable, depending on the amino acid that attaches to the tRNA. E) catalytic, making the tRNA a ribozyme.
Answer: A
30) Eukaryotic cells can control gene expression by which of the following mechanisms? A) histone acetylation of nucleosomes B) DNA acetylation C) RNA induced modification of chromatin structure D) repression of operons E) induction of operators in the promoter
Answer: A
30) Homeotic genes contain a homeobox sequence that is highly conserved among very diverse species. The homeobox is the code for that domain of a protein that binds to DNA in a regulatory developmental process. Which of the following would you then expect? A) That homeotic genes are selectively expressed over developmental time. B) That a homeobox containing gene has to be a developmental regulator. C) That homeoboxes cannot be expressed in non -homeotic genes. D) That all organisms must have homeotic genes. E) That all organisms must have homeobox containing genes.
Answer: A
30) Synapsis of homologous pairs occurs; crossing over may occur. A) I B) II C) IV D) VI E) VII
Answer: A
30) Which of the following is the best predictor of how much damage a virus causes? A) ability of the infected cell to undergo normal cell division B) ability of the infected cell to carry on translation C) whether the infected cell produces viral protein D) whether the viral mRNA can be transcribed E) how much toxin the virus produces
Answer: A
37) A researcher found a method she could use to manipulate and quantify phosphorylation and methylation in embryonic cells in culture. In one set of experiments she succeeded in decreasing methylation of histone tails. Which of the following results would she most likely see? A) increased chromatin condensation B) decreased chromatin concentration C) abnormalities of mouse embryos D) decreased binding of transcription factors E) inactivation of the selected genes
Answer: A
38) If a pair of homologous chromosomes fails to separate during anaphase of meiosis I, what will be the chromosome number of the four resulting gametes with respect to the normal haploid number (n)? A) n + 1; n + 1; n - 1; n - 1 B) n + 1; n - 1; n; n C) n + 1; n - 1; n - 1; n - 1 D) n + 1; n + 1; n; n E) n - 1; n - 1; n; n
Answer: A
38) The bonding of two amino acid molecules to form a larger molecule requires which of the following? A) removal of a water molecule B) addition of a water molecule C) formation of an ionic bond D) formation of a hydrogen bond E) both A and C
Answer: A
42) One inhibitor of cGMP is Viagra. It provides a signal that leads to dilation of blood vessels and increase of blood in the penis, facilitating erection. cGMP is inhibited, therefore the signal is prolonged. The original signal that is now inhibited would have A) hydrolyzed cGMP to GMP. B) hydrolyzed GTP to GDP. C) phosphorylated GDP. D) dephosphorylated cGMP. E) removed GMP from the cell.
Answer: A
14) Membrane receptors that attach phosphates to specific animo acids in proteins are A) not found in humans. B) called receptor tyrosine-kinases. C) a class of GTP G-protein signal receptors. D) associated with several bacterial diseases in humans. E) important in yeast mating factors that contain amino acids.
Answer: B
45) Cells can be described as having a cytoskeleton of internal structures that contribute to the shape, organization, and movement of the cell. Which of the following are part of the cytoskeleton? A) the nuclear envelope B) mitochondria C) microfilaments D) lysosomes E) nucleoli
Answer: A
62) In an experiment studying photosynthesis performed during the day, you provide a plant with radioactive carbon (14C) dioxide as a metabolic tracer. The 14C is incorporated first into oxaloacetate. The plant is best characterized as a A) C4 plant. B) C3 plant. C) CAM plant. D) heterotroph. E) chemoautotroph.
Answer: A
48) Assume that acid rain has lowered the pH of a particular lake to pH 4.0. What is the hydroxyl ion concentration of this lake? A) 1 × 10-10 mol of hydroxyl ion per liter of lake water B) 1 × 10-4 mol of hydroxyl ion per liter of lake water C) 10.0 M with regard to hydroxyl ion concentration D) 4.0 M with regard to hydroxyl ion concentration E) both B and D
Answer: A
56) The pedigree in Figure 15.4 shows the transmission of a trait in a particular family. Based on this pattern of transmission, the trait is most likely A) mitochondrial. B) autosomal recessive. C) sex- linked dominant. D) sex- linked recessive. E) autosomal dominant.
Answer: A
6) Which of the following molecules make up the viral envelope? A) glycoproteins B) proteosugars C) carbopeptides D) peptidocarbs E) carboproteins
Answer: A
9) Bacteria that do not take up any plasmids would grow on which media? A) the nutrient broth only B) the nutrient broth and the tetracycline broth C) the nutrient broth and the ampicillin broth D) the tetracycline broth and the ampicillin broth E) all four broths
Answer: A
A) 0.5 kilocalories per gram of wax burned B) 5 kilocalories per gram of wax burned C) 10 kilocalories per gram of wax burned D) 20 kilocalories per gram of wax burned E) 50 kilocalories per gram of wax burned
Answer: A
11) When T2 phages infect bacteria and make more viruses in the presence of radioactive sulfur, what is the result? A) The viral DNA will be radioactive. B) The viral proteins will be radioactive. C) The bacterial DNA will be radioactive. D) both A and B E) both A and C
Answer: B
29) Imagine that you are a genetic counselor, and a couple planning to start a family comes to you for information. Charles was married once before, and he and his first wife had a child with cystic fibrosis. The brother of his current wife, Elaine, died of cystic fibrosis. What is the probability that Charles and Elaine will have a baby with cystic fibrosis? (Neither Charles nor Elaine has cystic fibrosis.)
Answer: 1/6
24) Which extinct species should be the best candidate to serve as the outgroup for the clade whose common ancestor occurs at position 2? A) A B) B C) C D) D E) E
Answer: A
20) Replication in prokaryotes differs from replication in eukaryotes for which of these reasons? A) The prokaryotic chromosome has histones, whereas eukaryotic chromosomes do not. B) Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many. C) The rate of elongation during DNA replication is slower in prokaryotes than in eukaryotes. D) Prokaryotes produce Okazaki fragments during DNA replication, but eukaryotes do not. E) Prokaryotes have telomeres, and eukaryotes do not.
Answer: B
20) Where would you expect to find the carboxyl end? A) at the exterior surface B) at the cytosol surface C) connected with the loop at H5 and H6 D) between the membrane layers
Answer: B
27) In E. coli, there is a mutation in a gene called dnaB that alters the helicase that normally acts at the origin. Which of the following would you expect as a result of this mutation? A) No proofreading will occur. B) No replication fork will be formed. C) The DNA will supercoil. D) Replication will occur via RNA polymerase alone. E) Replication will require a DNA template from another source.
Answer: B
4) Which of the following statements concerning unsaturated fats is true? A) They are more common in animals than in plants. B) They have double bonds in the carbon chains of their fatty acids. C) They generally solidify at room temperature. D) They contain more hydrogen than saturated fats having the same number of carbon atoms. E) They have fewer fatty acid molecules per fat molecule.
Answer: B
5) The reactivity of an atom arises from A) the average distance of the outermost electron shell from the nucleus. B) the existence of unpaired electrons in the valence shell. C) the sum of the potential energies of all the electron shells. D) the potential energy of the valence shell. E) the energy difference between the s and p orbitals.
Answer: B
9) A controlled experiment is one that A) proceeds slowly enough that a scientist can make careful records of the results. B) may include experimental groups and control groups tested in parallel. C) is repeated many times to make sure the results are accurate. D) keeps all environmental variables constant. E) is supervised by an experienced scientist.
Answer: B
3) Homologous chromosomes move toward opposite poles of a dividing cell during A) mitosis. B) meiosis I. C) meiosis II. D) fertilization. E) binary fission.
Answer: B
3) The bonds that are broken when water vaporizes are A) ionic bonds. B) hydrogen bonds between water molecules. C) covalent bonds between atoms within water molecules. D) polar covalent bonds. E) nonpolar covalent bonds
Answer: B
30) What are the coding segments of a stretch of eukaryotic DNA called? A) introns B) exons C) codons D) replicons E) transposons
Answer: B
30) Which of the following is a characteristic feature of a carrier protein in a plasma membrane? A) It is a peripheral membrane protein. B) It exhibits a specificity for a particular type of molecule. C) It requires the expenditure of cellular energy to function. D) It works against diffusion. E) It has few, if any, hydrophobic amino acids.
Answer: B
4) A paleontologist has recovered a bit of tissue from the 400 -year-old preserved skin of an extinct dodo (a bird). The researcher would like to compare a specific region of the DNA from the sample with DNA from living birds. Which of the following would be most useful for increasing the amount of dodo DNA available for testing? A) RFLP analysis B) polymerase chain reaction (PCR) C) electroporation D) gel electrophoresis E) Southern blotting
Answer: B
3) A cross between homozygous purple - flowered and homozygous white- flowered pea plants results in offspring with purple flowers. This demonstrates A) the blending model of genetics. B) true-breeding. C) dominance. D) a dihybrid cross. E) the mistakes made by Mendel.
Answer: C
3) How is a physical map of the genome of an organism achieved? A) using recombination frequency B) using very high-powered microscopy C) using restriction enzyme cutting sites D) using sequencing of nucleotides E) using DNA fingerprinting via electrophoresis
Answer: C
3) Morgan and his colleagues worked out a set of symbols to represent fly genotypes. Which of the following are representative? A) AaBb × AaBb B) 46, XY or 46, XX C) vg+vgse+se × vgvgsese D) +2 × +3
Answer: C
9) A newspaper ad for a local toy store indicates that a very inexpensive microscope available for a small child is able to magnify specimens nearly as much as the much more costly microscope available in your college lab. What is the primary reason for the price difference? A) The ad agency is misrepresenting the ability of the toy microscope to magnify. B) The toy microscope does not have the same fine control for focus of the specimen. C) The toy microscope magnifies a good deal, but has low resolution and therefore poor quality images. D) The college microscope produces greater contrast in the specimens. E) The toy microscope usually uses a different wavelength of light source.
Answer: C
9) The enzyme polynucleotide phosphorylase randomly assembles nucleotides into a polynucleotide polymer. You add polynucleotide phosphorylase to a solution of adenosine triphosphate and guanosine triphosphate. How many artificial mRNA 3 nucleotide codons would be possible? A) 3 B) 4 C) 8 D) 16 E) 64
Answer: C
75) Male satin bowerbirds adorn structures that they build, called ʺbowers,ʺ with parrot feathers, flowers, and other bizarre ornaments in order to attract females. Females inspect the bowers and, if suitably impressed, allow males to mate with them. The evolution of this male behavior is due to A) frequency-dependent selection. B) artificial selection. C) sexual selection. D) natural selection. E) disruptive selection.
Answer: C
4) Emerging viruses arise by A) mutation of existing viruses. B) the spread of existing viruses to new host species. C) the spread of existing viruses more widely within their host species. D) all of the above E) none of the above
Answer: D
42) The peroxisome gets its name from its interaction with hydrogen peroxide. If a liver cell is detoxifying alcohol and some other poisons, it does so by removal of hydrogen from the molecules. What, then, do the enzymes of the peroxisome do? A) combine the hydrogen with ATP B) use the hydrogen to break down hydrogen peroxide C) transfer the harmful substances to the mitochondria D) transfer the hydrogens to oxygen molecules
Answer: D
1) If photosynthesizing green algae are provided with CO 2 synthesized with heavy oxygen (18O), later analysis will show that all but one of the following compounds produced by the algae contain the 18O label. That one is A) PGA. B) PGAL. C) glucose. D) RuBP. E) O2 .
Answer: E
1) Which term most precisely describes the cellular process of breaking down large molecules into smaller ones? A) catalysis B) metabolism C) anabolism D) dehydration E) catabolism
Answer: E
10) Which of the following is (are) true of ligand -gated ion channels? A) They are important in the nervous system. B) They lead to changes in sodium and calcium concentrations in cells. C) They open or close in response to a chemical signal. D) Only A and B are true. E) A, B, and C are true.
Answer: E
12) As a young biologist, Charles Darwin had expected the living plants of temperate South America would resemble those of temperate Europe, but he was surprised to find that they more closely resembled the plants of tropical South America. The biological explanation for this observation is most properly associated with the field of A) meteorology. B) embryology. C) vertebrate anatomy. D) bioengineering. E) biogeography.
Answer: E
29) In order to identify a specific restriction fragment using a probe, what must be done? A) The fragments must be separated by electrophoresis. B) The fragments must be treated with heat or chemicals to separate the strands of the double helix. C) The probe must be hybridized with the fragment. D) Only A and B are correct. E) A, B, and C are correct.
Answer: E
36) Chromatids are separated from each other. A) The statement is true for mitosis only. B) The statement is true for meiosis I only. C) The statement is true for meiosis II only. D) The statement is true for mitosis and meiosis I. E) The statement is true for mitosis and meiosis II.
Answer: E
49) What is the source of the extra chromosome 21 in an individual with Down syndrome? A) Nondisjunction in the mother only B) Nondisjunction in the father only C) Duplication of the chromosome D) Nondisjunction or translocation in either parent E) It is impossible to detect with current technology
Answer: D
57) In prophase I of meiosis in female Drosophila, studies have shown that there is phosphorylation of an amino acid in the tails of histones. A mutation in flies that interferes with this process results in sterility. Which of the following is the most likely hypothesis? A) These oocytes have no histones. B) Any mutation during oogenesis results in sterility. C) Phosphorylation of all proteins in the cell must result. D) Histone tail phosphorylation prohibits chromosome condensation. E) Histone tails must be removed from the rest of the histones.
Answer: D
57) Which of the following explains most specifically the attraction of water molecules to one another? A) nonpolar covalent bond B) polar covalent bond C) ionic bond D) hydrogen bond E) hydrophobic interaction
Answer: D
57) Which of the following is one of the technical reasons why gene therapy is problematic? A) Most cells with an engineered gene do not produce gene product. B) Most cells with engineered genes overwhelm other cells in a tissue. C) Cells with transferred genes are unlikely to replicate. D) Transferred genes may not have appropriately controlled activity. E) mRNA from transferred genes cannot be translated.
Answer: D
62) Which describes an African butterfly species that exists in two strikingly different color patterns? A) artificial selection B) directional selection C) stabilizing selection D) disruptive selection E) sexual selection
Answer: D
64) Why might a point mutation in DNA make a difference in the level of proteinʹs activity? A) It might result in a chromosomal translocation. B) It might exchange one stop codon for another stop codon. C) It might exchange one serine codon for a different serine codon. D) It might substitute an amino acid in the active site. E) It might substitute the N terminus of the polypeptide for the C terminus.
Answer: D
9) Imagine you want to study human crystallins, proteins present in the lens of the eye. To obtain a sufficient amount of the protein, you decide to clone the crystallin gene. Would you construct a genomic library or a cDNA library? What material would you use as a source of DNA or RNA? Answer: A cDNA library, made using mRNA from human lens cells, which would be
expected to contain many copies of crystallin mRNAs
10) Calcium has an atomic number of 20 and an atomic mass of 40. Therefore, a calcium atom must have A) 20 protons. B) 40 electrons. C) 40 neutrons. D) A and B only E) A, B, and C
Answer: A
21) Which of the following span the phospholipids bilayer, usually a number of times? A) transmembrane proteins B) integral proteins C) peripheral proteins D) integrins E) glycoproteins
Answer: A
47) Which bonds are created during the formation of the primary structure of a protein? A) peptide bonds B) hydrogen bonds C) disulfide bonds D) phosphodiester bonds E) A, B, and C
Answer: A
12) If, someday, an archaean cell is discovered whose SSU -rRNA sequence is more similar to that of humans than the sequence of mouse SSU-rRNA is to that of humans, the best explanation for this apparent discrepancy would be A) homology. B) homoplasy. C) common ancestry. D) retro-evolution by humans. E) co-evolution of humans and that archaean.
Answer: B
2) RNA viruses require their own supply of certain enzymes because A) host cells rapidly destroy the viruses. B) host cells lack enzymes that can replicate the viral genome. C) these enzymes translate viral mRNA into proteins. D) these enzymes penetrate host cell membranes. E) these enzymes cannot be made in host cells.
Answer: B
22) Why is ATP an important molecule in metabolism? A) Its hydrolysis provides an input of free energy for exergonic reactions. B) It provides energy coupling between exergonic and endergonic reactions. C) Its terminal phosphate group contains a strong covalent bond that when hydrolyzed releases free energy. D) Its terminal phosphate bond has higher energy than the other two. E) A, B, C, and D
Answer: B
34) A cell divides to produce two daughter cells that are genetically different. A) The statement is true for mitosis only. B) The statement is true for meiosis I only. C) The statement is true for meiosis II only. D) The statement is true for mitosis and meiosis I. E) The statement is true for mitosis and meiosis II.
Answer: B
36) A researcher found a method she could use to manipulate and quantify phosphorylation and methylation in embryonic cells in culture. In one set of experiments using this procedure in Drosophila, she was readily successful in increasing phosphorylation of amino acids adjacent to methylated amino acids in histone tails. Which of the following results would she most likely see? A) increased chromatin condensation B) decreased chromatin concentration C) abnormalities of mouse embryos D) decreased binding of transcription factors E) inactivation of the selected genes
Answer: B
55) When DNA is compacted by histones into 10 nm and 30 nm fibers, the DNA is unable to interact with proteins required for gene expression. Therefore, to allow for these proteins to act, the chromatin must constantly alter its structure. Which processes contribute to this dynamic activity? A) DNA supercoiling at or around H1 B) methylation and phosphorylation of histone tails C) hydrolysis of DNA molecules where they are wrapped around the nucleosome core D) accessibility of heterochromatin to phosphorylating enzymes E) nucleotide excision and reconstruction
Answer: B
55) When translating secretory or membrane proteins, ribosomes are directed to the ER membrane by A) a specific characteristic of the ribosome itself, which distinguishes free ribosomes from bound ribosomes. B) a signal-recognition particle that brings ribosomes to a receptor protein in the ER membrane. C) moving through a specialized channel of the nucleus. D) a chemical signal given off by the ER. E) a signal sequence of RNA that precedes the start codon of the message.
Answer: B
7) Which component is not directly involved in translation? A) mRNA B) DNA C) tRNA D) ribosomes E) GTP
Answer: B
27) In mitochondria, chemiosmosis translocates protons from the matrix into the intermembrane space, whereas in chloroplasts, chemiosmosis translocates protons from A) the stroma to the photosystem II. B) the matrix to the stroma. C) the stroma to the thylakoid space. D) the intermembrane space to the matrix. E) ATP synthase to NADP + reductase.
Answer: C
46) Gene flow is a concept best used to describe an exchange between A) species. B) males and females. C) populations. D) individuals. E) chromosomes.
Answer: C
72) An important group of peripheral membrane proteins are enzymes, such as the phospholipases that attack the head groups of phospholipids leading to the degradation of damaged membranes. What properties must these enzymes exhibit? A) resistance to degradation B) independence from cofactor interaction C) water solubility D) lipid solubility E) membrane spanning domains
Answer: C
72) If a DNA sample were composed of 10% thymine, what would be the percentage of guanine? A) 10 B) 20 C) 40 D) 80 E) impossible to tell from the information given
Answer: C
73) These genes are expressed by the mother, and their products are deposited into the developing egg: A) homeotic genes B) segmentation genes C) egg-polarity genes D) morphogens E) inducers
Answer: C
74) A group of molecular biologists is trying to synthesize a new artificial compound to mimic the effects of a known hormone that influences sexual behavior. They have turned to you for advice. Which of the following compounds is most likely to mimic the effects of the hormone? A) a compound with the same number of carbon atoms as the hormone B) a compound with the same molecular mass (measured in daltons) as the hormone C) a compound with the same three -dimensional shape as part of the hormone D) a compound with the same number of orbital electrons as the hormone E) a compound with the same number of hydrogen and nitrogen atoms as the hormone
Answer: C
3) Select the factor most likely to have caused the animals and plants of India to differ greatly from species in nearby Southeast Asia. A) The species have become separated by convergent evolution. B) The climates of the two regions are similar. C) India is in the process of separating from the rest of Asia. D) Life in India was wiped out by ancient volcanic eruptions. E) India was a separate continent until 55 million years ago.
Answer: E
43) Which of the following is most closely identical to the formation of twins? A) cell cloning B) therapeutic cloning C) use of adult stem cells D) embryo transfer E) organismal cloning
Answer: E
52) Which of the following is an example of polygenic inheritance? A) Pink flowers in snapdragons B) The ABO blood groups in humans C) Huntingtonʹs disease in humans D) White and purple flower color in peas E) Skin pigmentation in humans
Answer: E
59) Approximately how many molecules of ATP are produced from the complete oxidation of two molecules of glucose (C 6H12O6 ) in cellular respiration? A) 2 B) 4 C) 15 D) 38 E) 76
Answer: E
67) Which of the following is true concerning cancer cells? A) They do not exhibit density-dependent inhibition when growing in culture. B) When they stop dividing, they do so at random points in the cell cycle. C) They are not subject to cell cycle controls. D) B and C only E) A, B, and C
Answer: E
74) The difference between the sugar in DNA and the sugar in RNA is that the sugar in DNA A) is a six-carbon sugar and the sugar in RNA is a five-carbon sugar. B) can form a double -stranded molecule. C) has a six-membered ring of carbon and nitrogen atoms. D) can attach to a phosphate. E) contains one less oxygen atom.
Answer: E
9) Although absolute distinctions between the ʺmost evolvedʺ protobiont and the first living cell are unclear, biologists generally agree that one major difference is that the typical protobiont could not A) possess a selectively permeable membrane boundary. B) perform osmosis. C) grow in size. D) perform controlled, precise reproduction. E) absorb compounds from the external environment.
Answer: D
9) Based on the above table, which virus meets the Baltimore requirements for a retrovirus?
Answer: D
12) Figure 10.1 shows the absorption spectrum for chlorophyll a and the action spectrum for photosynthesis. Why are they different? A) Green and yellow wavelengths inhibit the absorption of red and blue wavelengths. B) Bright sunlight destroys photosynthetic pigments. C) Oxygen given off during photosynthesis interferes with the absorption of light. D) Other pigments absorb light in addition to chlorophyll a. E) Aerobic bacteria take up oxygen which changes the measurement of the rate of photosynthesis.
Answer: D
9) The lactose operon is likely to be transcribed when A) there is more glucose in the cell than lactose. B) the cyclic AMP levels are low. C) there is glucose but no lactose in the cell. D) the cyclic AMP and lactose levels are both high within the cell. E) the cAMP level is high and the lactose level is low.
Answer: D
9) The nutritional information on a cereal box shows that one serving of a dry cereal has 200 kilocalories. If one were to burn one serving of the cereal, the amount of heat given off would be sufficient to raise the temperature of 20 kg of water how many degrees Celsius? A) 0.2°C B) 1.0°C C) 2.0°C D) 10.0°C E) 20.0°C
Answer: D
12) Fragments of DNA have been extracted from the remnants of extinct wooly mammoths, amplified, and sequenced. These can now be used to A) introduce into relatives, such as elephants, certain mammoth traits. B) clone live wooly mammoths. C) study the relationships among wooly mammoths and other wool -producers. D) understand the evolutionary relationships among members of related taxa. E) appreciate the reasons why mammoths went extinct
Answer: D
12) In cats, black fur color is caused by an X- linked allele; the other allele at this locus causes orange color. The heterozygote is tortoiseshell. What kinds of offspring would you expect from the cross of a black female and an orange male? A) Tortoiseshell females; tortoiseshell males B) Black females; orange males C) Orange females; orange males D) Tortoiseshell females; black males E) Orange females; black males
Answer: D
12) One species mates at the season when daylight is increasing from 13 hours to 13 hours, 15 minutes; another species mates at the season when daylight is increasing from 14 hours to 14 hours, 15 minutes. A) behavioral B) gametic C) habitat D) temporal E) mechanical
Answer: D
12) What amino acid sequence will be generated, based on the following mRNA codon sequence? 5ʹ AUG-UCU-UCG-UUA-UCC-UUG 3ʹ A) met-arg-glu-arg-glu-arg B) met-glu-arg-arg-gln- leu C) met-ser- leu-ser- leu-ser D) met-ser-ser- leu-ser- leu E) met- leu-phe-arg-glu-glu
Answer: D
12) Which of the following accounts for someone who has had a herpesvirus -mediated cold sore or genital sore getting flare -ups for the rest of life? A) re- infection by a closely related herpesvirus of a different strain B) re- infection by the same herpesvirus strain C) co- infection with an unrelated virus that causes the same symptoms D) copies of the herpesvirus genome permanently maintained in host nuclei E) copies of the herpesvirus genome permanently maintained in host cell cytoplasm
Answer: D
12) Why are yeast cells frequently used as hosts for cloning? A) they easily form colonies B) they can remove exons from mRNA. C) they do not have plasmids. D) they are eukaryotic cells E) only yeast cells allow the gene to be cloned
Answer: D
13) If cells in the process of dividing are subjected to colchicine, a drug that interferes with the functioning of the spindle apparatus, at which stage will mitosis be arrested? A) anaphase B) prophase C) telophase D) metaphase E) interphase
Answer: D
13) Which of the boxes correspond to plants with a heterozygous genotype? A) 1 B) 1 and 2 C) 1, 2, and 3 D) 2 and 3 E) 2, 3, and 4
Answer: D
13) Which of the following is true of metabolism in its entirety? A) Metabolism depends on a constant supply of energy from food B) Metabolism depends on an organismʹs adequate hydration C) Metabolism utilizes all of an organismʹs resources D) Metabolism is a property of organismal life E) Metabolism manages the increase of entropy in an organism
Answer: D
13) Which of these statements is false? A) In humans, each of the 22 maternal autosomes has a homologous paternal chromosome. B) In humans, the 23rd pair, the sex chromosomes, determines whether the person is female (XX) or male (XY). C) Single, haploid (n) sets of chromosomes in ovum and sperm unite during fertilization, forming a diploid (2n), single-celled zygote. D) At sexual maturity, ovaries and testes produce diploid gametes by meiosis. E) Sexual life cycles differ with respect to the relative timing of meiosis and fertilization.
Answer: D
14) A cell containing 92 chromatids at metaphase of mitosis would, at its completion, produce two nuclei each containing how many chromosomes? A) 12 B) 16 C) 23 D) 46 E) 92
Answer: D
14) Charles Darwin was the first person to propose A) that evolution occurs. B) a mechanism for how evolution occurs. C) that the Earth is older than a few thousand years. D) a mechanism for evolution that was supported by evidence. E) a way to use artificial selection as a means of domesticating plants and animals.
Answer: D
14) Dog breeders maintain the purity of breeds by keeping dogs of different breeds apart when they are fertile. This kind of isolation is most similar to which of the following reproductive isolating mechanisms? A) reduced hybrid fertility B) hybrid breakdown C) mechanical isolation D) habitat isolation E) gametic isolation
Answer: D
14) Which of the following is a major cause of the size limits for certain types of cells? A) the evolution of larger cells after the evolution of smaller cells B) the difference in plasma membranes between prokaryotes and eukaryotes C) the evolution of eukaryotes after the evolution of prokaryotes D) the need for a surface area of sufficient area to allow the cellʹs function E) the observation that longer cells usually have greater cell volume
Answer: D
14) Which of the following is characteristic of the lytic cycle? A) Many bacterial cells containing viral DNA are produced. B) Viral DNA is incorporated into the host genome. C) The viral genome replicates without destroying the host. D) A large number of phages is released at a time. E) The virus-host relationship usually lasts for generations.
Answer: D
14) Which statement about variation is true? A) All phenotypic variation is the result of genotypic variation. B) All genetic variation produces phenotypic variation. C) All nucleotide variability results in neutral variation. D) All new alleles are the result of nucleotide variability. E) All geographic variation results from the existence of clines.
Answer: D
14) Why does ice float in liquid water? A) The liquid water molecules have more kinetic energy and thus support the ice. B) The ionic bonds between the molecules in ice prevent the ice from sinking. C) Ice always has air bubbles that keep it afloat. D) Hydrogen bonds stabilize and keep the molecules of ice farther apart than the water molecules of liquid water. E) The crystalline lattice of ice causes it to be denser than liquid water.
Answer: D
15) Some molecular data place the giant panda in the bear family (Ursidae) but place the lesser panda in the raccoon family (Procyonidae). Consequently, the morphological similarities of these two species are probably due to A) inheritance of acquired characteristics. B) sexual selection. C) inheritance of shared derived characters. D) possession of analogous structures. E) possession of shared primitive characters.
Answer: D
15) Up to 60% of all medicines used today exert their effects by influencing what structures in the cell membrane? A) tyrosine-kinases receptors B) ligand-gated ion channel receptors C) growth factors D) G proteins E) cholesterol
Answer: D
15) When a membrane is freeze- fractured, the bilayer splits down the middle between the two layers of phospholipids. In an electron micrograph of a freeze - fractured membrane, the bumps seen on the fractured surface of the membrane are A) peripheral proteins. B) phospholipids. C) carbohydrates. D) integral proteins. E) cholesterol molecules.
Answer: D
16) If natural selection in a particular environment favored genetic systems that permitted the production of daughter ʺcellsʺ that were genetically dissimilar from the mother ʺcells,ʺ then one should expect selection for I. polynucleotide polymerase with low mismatch error rates. II. polynucleotide polymerases without proofreading capability. III. batteries of efficient polynucleotide repair enzymes. IV. polynucleotide polymerases with proofreading capability. V. polynucleotide polymerases with high mismatch error rates. A) I only B) I and IV C) I, III, and IV D) II and V E) II, III and V
Answer: D
16) If she moves the promoter for the lac operon to the region between the beta galactosidase gene and the permease gene, which of the following would be likely? A) Three structural genes will no longer be expressed. B) RNA polymerase will no longer transcribe permease. C) The operon will no longer be inducible. D) Beta galactosidase will be produced. E) The cell will continue to metabolize but more slowly.
Answer: D
16) In angiosperm plants, flower morphology can be very intricate. If a tree, such as a New Mexico locust, has flowers that share many morphological intricacies with flowers of the sweet pea vine, then the most likely explanation for these floral similarities is the same general explanation for the similarities between the A) dorsal fins of sharks and of dolphins. B) reduced eyes of Australian moles and North American moles. C) scales on moth wings and the scales of fish skin. D) cranial bones of humans and those of chimpanzees. E) adaptations for flight in birds and adaptations for flight in bats.
Answer: D
17) 3 H is a radioactive isotope of hydrogen. One difference between hydrogen -1 ( 1 1 hydrogen-3 ( 3 1 H) is that hydrogen-3 has A) one more neutron and one more proton than hydrogen -1. B) one more proton and one more electron than hydrogen -1. C) one more electron and one more neutron than hydrogen -1. D) two more neutrons than hydrogen -1. E) two more protons than hydrogen-1.
Answer: D
17) Chemical equilibrium is relatively rare in living cells. Which of the following could be an example of a reaction at chemical equilibrium in a cell? A) a reaction in which the free energy at equilibrium is higher than the energy content at any point away from equilibrium B) a chemical reaction in which the entropy change in the reaction is just balanced by an opposite entropy change in the cellʹs surroundings C) an endergonic reaction in an active metabolic pathway where the energy for that reaction is supplied only by heat from the environment D) a chemical reaction in which both the reactants and products are only used in a metabolic pathway that is completely inactive E) There is no possibility of having chemical equilibrium in any living cell.
Answer: D
17) If she moves the operator to the far end of the operon (past the transacetylase gene), which of the following would likely occur when the cell is exposed to lactose? A) The inducer will no longer bind to the repressor. B) The repressor will no longer bind to the operator. C) The operon will never be transcribed. D) The structural genes will be transcribed continuously. E) The repressor protein will no longer be produced.
Answer: D
90) Even though plants carry on photosynthesis, plant cells still use their mitochondria for oxidation of pyruvate. When and where will this occur? A) in photosynthetic cells in the light, while photosynthesis occurs concurrently B) in non-photosynthesizing cells only C) in cells that are storing glucose only D) in photosynthesizing cells in dark periods and in other tissues all the time E) in photosynthesizing cells in the light and in other tissues in the dark
Answer: D
95) Which of the following molecules could be joined together by a phosphodiester type of covalent bond? A) 3 and 4 B) 3 and 8 C) 6 and 15 D) 11 and 12 E) 11 and 13
Answer: D
96) Which of the following molecules is the pentose sugar found in RNA? A) 1 B) 4 C) 6 D) 12 E) 13
Answer: D
17) Sponges are known to contain a single Hox gene. Most invertebrates have a cluster of 10 similar Hox genes, all located on the same chromosome. Most vertebrates have four such clusters of Hox genes, located on four non-homologous chromosomes. The process responsible for the change in number of Hox genes from sponges to invertebrates was most likely __________, whereas a different process that could have potentially contributed to the clusterʹs presence on more than one chromosome was __________. I. binary fission II. translation III. gene duplication IV. non-disjunction V. transcription A) I, II B) II, III C) II, V D) III, IV E) III, V
Answer: D
17) The fact that all seven of the pea plant traits studied by Mendel obeyed the principle of independent assortment most probably indicates which of the following? A) None of the traits obeyed the law of segregation. B) The diploid number of chromosomes in the pea plants was 7. C) All of the genes controlling the traits were located on the same chromosome. D) All of the genes controlling the traits behaved as if they were on different chromosomes. E) The formation of gametes in plants occurs by mitosis only.
Answer: D
17) Which of the following nucleotide triplets best represents a codon? A) a triplet separated spatially from other triplets B) a triplet that has no corresponding amino acid C) a triplet at the opposite end of tRNA from the attachment site of the amino acid D) a triplet in the same reading frame as an upstream AUG E) a sequence in tRNA at the 3ʹ end
Answer: D
18) Which is true of transcription factors? A) They regulate the synthesis of DNA in response to a signal. B) Some transcribe ATP into cAMP. C) They initiate the epinephrine response in animal cells. D) They control which genes are expressed. E) They are needed to regulate the synthesis of lipids in the cytoplasm.
Answer: D
18) Which of the following is a major distinction between a transposon and a retrotransposon? A) A transposon always leaves a copy of itself at its original position and a retrotransposon does not. B) A retrotransposon always uses the copy-paste mechanism, while a transposon uses cut and paste mechanism. C) A transposon is related to a virus and a retrotransposon is not. D) A transposon moves via a DNA intermediate and a retrotransposon via an RNA intermediate. E) The positioning of a transposon copy is transient while that of a retrotransposon is permanent.
Answer: D
18) Which of these represents the treatment option that is most likely to avoid the production of drug- resistant HIV (assuming no drug interactions or side effects)? A) using a series of NAs, one at a time, and changed about once a week B) using a single PI, but slowly increasing the dosage over the course of a week C) using high doses of NA and a PI at the same time for a period not to exceed 1 day D) using moderate doses of NA and of two different PIʹs at the same time for several months
Answer: D
18) Which statement describes the functioning of photosystem II? A) Light energy excites electrons in the electron transport chain in a photosynthetic unit. B) The excitation is passed along to a molecule of P700 chlorophyll in the photosynthetic unit. C) The P680 chlorophyll donates a pair of protons to NADPH, which is thus converted to NADP+ . D) The electron vacancies in P680 are filled by electrons derived from water. E) The splitting of water yields molecular carbon dioxide as a by-product.
Answer: D
19) Chemical signal pathways A) operate in animals, but not in plants. B) are absent in bacteria, but are plentiful in yeast. C) involve the release of hormones into the blood. D) often involve the binding of signal molecules to a protein on the surface of a target cell. E) use hydrophilic molecules to activate enzymes.
Answer: D
19) In which of the following actions does RNA polymerase differ from DNA polymerase? A) RNA polymerase uses RNA as a template, and DNA polymerase uses a DNA template. B) RNA polymerase binds to single -stranded DNA, and DNA polymerase binds to double-stranded DNA. C) RNA polymerase is much more accurate than DNA polymerase. D) RNA polymerase can initiate RNA synthesis, but DNA polymerase requires a primer to initiate DNA synthesis. E) RNA polymerase does not need to separate the two strands of DNA in order to synthesize an RNA copy, whereas DNA polymerase must unwind the double helix before it can replicate the DNA.
Answer: D
19) Mendelʹs observation of the segregation of alleles in gamete formation has its basis in which of the following phases of cell division? A) Prophase I of meiosis B) Prophase II of meiosis C) Metaphase I of meiosis D) Anaphase I of meiosis E) Anaphase of mitosis
Answer: D
19) Which statement about natural selection is most correct? A) Adaptations beneficial in one habitat should generally be beneficial in all other habitats as well. B) Different species that occupy the same habitat will adapt to that habitat by undergoing the same genetic changes. C) Adaptations beneficial at one time should generally be beneficial during all other times as well. D) Well-adapted individuals leave more offspring, and thus contribute more to the next generationʹs gene pool, than do poorly adapted individuals. E) Natural selection is the sole means by which populations can evolve.
Answer: D
2) Binding of a signaling molecule to which type of receptor leads directly to a change in distribution of ions on opposite sides of the membrane? A) receptor tyrosine kinase B) G protein-coupled receptor C) phosphorylated receptor tyrosine kinase dimer D) ligand-gated ion channel E) intracellular receptor
Answer: D
2) E. coli cells grown on 15N medium are transferred to 14N medium and allowed to grow for two more generations (two rounds of DNA replication). DNA extracted from these cells is centrifuged. What density distribution of DNA would you expect in this experiment? A) one high-density and one low-density band B) one intermediate-density band C) one high-density and one intermediate-density band D) one low-density and one intermediate-density band E) one low-density band
Answer: D
2) Which of the events described below agrees with the idea of catastrophism? A) The gradual uplift of the Himalayas by the collision of the Australian crustal plate with the Eurasian crustal plate B) The formation of the Grand Canyon by the Colorado River over millions of years C) The gradual deposition of sediments many kilometers thick on the floors of seas and oceans D) The sudden demise of the dinosaurs, and various other groups, by the impact of a large extraterrestrial body with Earth E) The development of the Galapagos Islands from underwater seamounts over millions of years
Answer: D
2) Which of the following is not a theme that unifies biology? A) interaction with the environment B) emergent properties C) evolution D) reductionism E) structure and function
Answer: D
2) Which of the following is not true of a codon? A) It consists of three nucleotides. B) It may code for the same amino acid as another codon. C) It never codes for more than one amino acid. D) It extends from one end of a tRNA molecule. E) It is the basic unit of the genetic code.
Answer: D
2) Which of the following statements about genes is incorrect? A) Genes correspond to segments of DNA. B) Many genes contain the information needed for cells to synthesize enzymes and other proteins. C) During fertilization, both the sperm and the ovum contribute genes to the resulting fertilized egg. D) One gene only is used in a specific cell type. E) Genetic differences can result from changes in the DNA called mutations.
Answer: D
20) How many half - lives should have elapsed if 6.25% of the parent isotope remains in a fossil at the time of analysis? A) one B) two C) three D) four E) five
Answer: D
20) In the years since the proposal of the fluid mosaic model of the cell membrane, which of the following observations has been added to the model? A) The membrane is only fluid across a very narrow temperature range. B) Proteins rarely move, even though they possibly can do so. C) Unsaturated lipids are excluded from the membranes. D) The concentration of protein molecules is now known to be much higher. E) The proteins are known to be made of only acidic amino acids.
Answer: D
20) Muscle cells and nerve cells in one species of animal owe their differences in structure to A) having different genes. B) having different chromosomes. C) using different genetic codes. D) having different genes expressed. E) having unique ribosomes.
Answer: D
20) Sequencing an entire genome, such as that of C. elegans , a nematode, is most important because A) it allows researchers to use the sequence to build a ʺbetterʺ nematode, resistant to disease. B) it allows research on a group of organisms we do not usually care much about. C) the nematode is a good animal model for trying out cures for viral illness. D) a sequence that is found to have a particular function in the nematode is likely to have a closely related function in vertebrates. E) a sequence that is found to have no introns in the nematode genome is likely to have acquired the introns from higher organisms.
Answer: D
20) The atomic number of neon is 10. Therefore, which of the following is correct about an atom of neon? A) It has 8 electrons in its outer electron shell. B) It is inert. C) It has an atomic mass of 10 daltons. D) A and B only E) A, B, and C are correct.
Answer: D
20) Which of the following is true of cellulose? A) It is a polymer composed of sucrose monomers. B) It is a storage polysaccharide for energy in plant cells. C) It is a storage polysaccharide for energy in animal cells. D) It is a major structural component of plant cell walls. E) It is a major structural component of animal cell plasma membranes.
Answer: D
21) Approximately how far back in time does the fossil record extend? A) 6,000 years B) 3,500,000 years C) 6,000,000 years D) 3,500,000,000 years E) 5,000,000,000,000 years
Answer: D
21) Black fur in mice (B) is dominant to brown fur ( b). Short tails (T) are dominant to long tails (t). What fraction of the progeny of the cross BbTt × BBtt will have black fur and long tails? A) 1/16 B) 3/16 C) 3/8 D) 1/2 E) 9/16
Answer: D
22) Assuming that the rate of sea- floor spreading was constant during the 1 -million-year period depicted above, Earthʹs magnetic field has undergone reversal at an average rate of once every A) 10,000 years. B) 25,000 years. C) 100,000 years. D) 250,000 years. E) 1,000,000 years.
Answer: D
22) Cytokinesis usually, but not always, follows mitosis. If a cell completed mitosis but not cytokinesis, the result would be a cell with A) a single large nucleus. B) high concentrations of actin and myosin. C) two abnormally small nuclei. D) two nuclei. E) two nuclei but with half the amount of DNA.
Answer: D
22) How might identical and obviously duplicated gene sequences have gotten from one chromosome to another? A) by normal meiotic recombination B) by normal mitotic recombination between sister chromatids C) by transcription followed by recombination D) by chromosomal translocation E) by deletion followed by insertion
Answer: D
23) A rapid method of speciation that has been important in the history of flowering plants is A) genetic drift. B) a mutation in the gene controlling the timing of flowering. C) behavioral isolation. D) polyploidy.
Answer: D
23) In the late 1950s, Meselson and Stahl grew bacteria in a medium containing ʺheavyʺ nitrogen (15N) and then transferred them to a medium containing 14N. Which of the results in Figure 16.1 would be expected after one round of DNA replication in the presence of 14N?
Answer: D
23) Which of these are attached to the extracellular matrix? A) transmembrane proteins B) integral proteins C) peripheral proteins D) integrins E) glycoproteins
Answer: D
24) During drought years on the Galapagos, small, easily eaten seeds become rare, leaving mostly large, hard -cased seeds that only birds with large beaks can eat. If a drought persists for several years, what should one expect to result from natural selection? A) Small birds gaining larger beaks by exercising their mouth parts. B) Small birds mutating their beak genes with the result that later -generation offspring have larger beaks. C) Small birds anticipating the long drought and eating more to gain weight and, consequently, growing larger beaks. D) More small-beaked birds dying than larger-beaked birds. The offspring produced in subsequent generations have a higher percentage of birds with large beaks. E) Larger birds eating less so smaller birds can survive.
Answer: D
24) One of the major categories of receptors in the plasma membrane reacts by forming dimmers, adding phosphate groups, then activating relay proteins. Which type does this? A) G protein- linked receptor B) ligand-gated ion channels C) steroid receptors D) receptor tyrosine kinases
Answer: D
25) How many grams of the molecule in Figure 3.2 would be required to make 2.5 L of a 1 M solution of the molecule? (Carbon = 12, Oxygen = 16, Hydrogen = 1) A) 29 B) 30 C) 60 D) 150 E) 342
Answer: D
25) Once the pattern found after one round of replication was observed, Meselson and Stahl could be confident of which of the following conclusions? A) Replication is semi-conservative. B) Replication is not dispersive. C) Replication is not semi-conservative. D) Replication is not conservative. E) Replication is neither dispersive nor conservative.
Answer: D
25) The receptors for a group of signaling molecules known as growth factors are often A) ligand-gated ion channels. B) G-protein- linked receptors. C) cyclic AMP. D) receptor tyrosine kinases. E) neurotransmitters.
Answer: D
25) Transcription in eukaryotes requires which of the following in addition to RNA polymerase? A) the protein product of the promoter B) start and stop codons C) ribosomes and tRNA D) several transcription factors (TFs) E) aminoacyl synthetase
Answer: D
25) Two potential devices that eukaryotic cells use to regulate transcription are A) DNA methylation and histone amplification. B) DNA amplification and histone methylation. C) DNA acetylation and methylation. D) DNA methylation and histone acetylation. E) histone amplification and DNA acetylation.
Answer: D
26) A molecule that is phosphorylated A) has been reduced as a result of a redox reaction involving the loss of an inorganic phosphate. B) has a decreased chemical reactivity; it is less likely to provide energy for cellular work. C) has been oxidized as a result of a redox reaction involving the gain of an inorganic phosphate. D) has an increased chemical reactivity; it is primed to do cellular work. E) has less energy than before its phosphorylation and therefore less energy for cellular work.
Answer: D
26) After telophase I of meiosis, the chromosomal makeup of each daughter cell is A) diploid, and the chromosomes are each composed of a single chromatid. B) diploid, and the chromosomes are each composed of two chromatids. C) haploid, and the chromosomes are each composed of a single chromatid. D) haploid, and the chromosomes are each composed of two chromatids. E) tetraploid, and the chromosomes are each composed of two chromatids.
Answer: D
26) Among known plant species, which of these have been the two most commonly occurring phenomena leading to the origin of new species? 1. allopatric speciation 2. sympatric speciation 3. sexual selection 4. polyploidy A) 1 and 3 B) 1 and 4 C) 2 and 3 D) 2 and 4
Answer: D
67) A certain species of land snail exists as either a cream color or a solid brown color. Intermediate individuals are relatively rare. Which of the following terms best describes this? A) artificial selection B) directional selection C) stabilizing selection D) disruptive selection E) sexual selection
Answer: D
26) Argon-40, the daughter isotope of potassium -40, is a gas. Elemental potassium has an atomic mass of about 39. If the submersible robot (which is equipped with a drill that is long enough to get to the igneous rock) ascends from depth too quickly, gases trapped within igneous rock may rapidly expand, fracture the rock, and escape from the sample before it can be dated aboard the floating research vessel. Rock samples can also absorb argon gas. Which of these techniques has the highest chance of providing inaccurate dates of igneous rocks distant from the rift valley, and what type of inaccuracy would it cause? A) if the date of the rock is determined by comparing the ratio of potassium -40 to potassium-39, underestimation of age B) if the submersible robot is retrieved from the sea floor at a very slow speed, overestimation of age C) if the submersible robot is equipped with a decompression chamber for the samples, underestimation of age D) if the submersible robot keeps the sample in a chamber of pure argon at high pressure, overestimation of age
Answer: D
27) How do cells at the completion of meiosis compare with cells that have replicated their DNA and are just about to begin meiosis? A) They have twice the amount of cytoplasm and half the amount of DNA. B) They have half the number of chromosomes and half the amount of DNA. C) They have the same number of chromosomes and half the amount of DNA. D) They have half the number of chromosomes and one - fourth the amount of DNA. E) They have half the amount of cytoplasm and twice the amount of DNA.
Answer: D
27) Which of the following is true of the evolution of cell membranes? A) Cell membranes have stopped evolving now that they are fluid mosaics. B) Cell membranes cannot evolve if proteins do not. C) The evolution of cell membranes is driven by the evolution of glycoproteins and glycolipids. D) As populations of organisms evolve, different properties of their cell membranes are selected for or against. E) An individual organism selects its preferred type of cell membrane for particular functions.
Answer: D
27) Which of the following s eparates molecules by movement due to size and electrical charge? A) restriction enzymes B) gene cloning C) DNA ligase D) gel electrophoresis E) reverse transcriptase
Answer: D
27) Which of the following statements is true regarding the molecule illustrated in Figure 5.2? A) It is a saturated fatty acid. B) A diet rich in this molecule may contribute to atherosclerosis. C) Molecules of this type are usually liquid at room temperature. D) A and B only E) A, B and C
Answer: D
28) If a fossil is encased in a stratum of sedimentary rock without any strata of igneous rock (e.g., lava, volcanic ash) nearby, then it should be A) easy to determine the absolute age of the fossil, because the radioisotopes in the sediments will not have been ʺresetʺ by the heat of the igneous rocks. B) easy to determine the absolute age of the fossil, because the igneous rocks will not have physically obstructed the deposition of sediment of a single age next to the fossil. C) difficult to determine the absolute age of the fossil, because the ʺmarker fossilsʺ common to igneous rock will be absent. D) difficult to determine the absolute age of the fossil, because radiometric dating of sedimentary rock is less accurate than that of igneous rock.
Answer: D
28) When ATP releases some energy, it also releases inorganic phosphate. What purpose does this serve (if any) in the cell? A) It is released as an excretory waste. B) It can only be used to regenerate more ATP. C) It can be added to water and excreted as a liquid. D) It can be added to other molecules in order to activate them. E) It can enter the nucleus to affect gene expression.
Answer: D
28) Which of the following produces and modifies polysaccharides that will be secreted? A) lysosome B) vacuole C) mitochondrion D) Golgi apparatus E) peroxisome
Answer: D
29) According to this tree, what percent of the species seem to be extant (i.e., not extinct)? A) 25% B) 33% C) 50% D) 66% E) 75%
Answer: D
29) If true-breeding red long radishes are crossed with true breeding white oval radishes, the F1 will be expected to be which of the following? A) Red and long B) Red and oval C) White and long D) Purple and long E) Purple and oval
Answer: D
29) In which group of eukaryotic organisms does the nuclear envelope remain intact during mitosis? A) seedless plants B) dinoflagellates C) diatoms D) B and C only E) A, B, and C
Answer: D
29) The phenomenon of fusion is likely to occur when, after a period of geographic isolation, two populations meet again and A) their chromosomes are no longer homologous enough to permit meiosis. B) a constant number of viable, fertile hybrids is produced over the course of generations. C) the hybrid zone is inhospitable to hybrid survival. D) an increasing number of viable, fertile hybrids is produced over the course of generations E) a decreasing number of viable, fertile hybrids is produced over the course of generations.
Answer: D
3) A primary objective of cell fractionation is to A) view the structure of cell membranes. B) identify the enzymes outside the organelles. C) determine the size of various organelles. D) separate the major organelles so that their particular functions can be determined. E) crack the cell wall so the cytoplasmic contents can be released.
Answer: D
3) About which of these did Darwin have a poor understanding? A) that individuals in a population exhibit a good deal of variation B) that much of the variation between individuals in a population is inherited C) the factors that cause individuals in populations to struggle for survival D) the sources of genetic variations among individuals E) how a beneficial trait becomes more common in a population over the course of generations
Answer: D
3) Cells of the pancreas will incorporate radioactively labeled amino acids into proteins. This ʺtaggingʺ of newly synthesized proteins enables a researcher to track their location. In this case, we are tracking an enzyme secreted by pancreatic cells. What is its most likely pathway? A) ER → Golgi → nucleus B) Golgi → ER → lysosome C) nucleus → ER → Golgi D) ER → Golgi → vesicles that fuse with plasma membrane E) ER → lysosomes → vesicles that fuse with plasma membrane
Answer: D
3) What could happen to the target cells in an animal that lack receptors for local regulators? A) They could compensate by receiving nutrients via an a factor. B) They could develop normally in response to neurotransmitters instead. C) They could divide but never reach full size. D) They would not be able to multiply in response to growth factors from nearby cells. E) Hormones would not be able to interact with target cells.
Answer: D
3) What is the enzymatic function of restriction enzymes? A) to add new nucleotides to the growing strand of DNA B) to join nucleotides during replication C) to join nucleotides during transcription D) to cleave nucleic acids at specific sites E) to repair breaks in sugar -phosphate backbones
Answer: D
3) What would occur if the repressor of an inducible operon were mutated so it could not bind the operator? A) irreversible binding of the repressor to the promoter B) reduced transcription of the operonʹs genes C) buildup of a substrate for the pathway controlled by the operon D) continuous transcription of the operonʹs genes E) overproduction of catabolite activator protein (CAP)
Answer: D
30) An early consequence of the release of oxygen gas by plant and bacterial photosynthesis was to A) make life on land difficult for aerobic organisms. B) change the atmosphere from oxidizing to reducing. C) make it easier to maintain reduced molecules. D) cause iron in ocean water and terrestrial rocks to rust (oxidize). E) prevent the formation of an ozone layer.
Answer: D
30) In a series of mapping experiments, the recombination frequencies for four different linked genes of Drosophila were determined as shown in the figure. What is the order of these genes on a chromosome map? A) rb-cn-vg-b B) vg-b-rb-cn C) cn- rb-b-vg D) b-rb-cn-vg E) vg-cn-b-rb
Answer: D
30) Movement of the chromosomes during anaphase would be most affected by a drug that A) reduces cyclin concentrations. B) increases cyclin concentrations. C) prevents elongation of microtubules. D) prevents shortening of microtubules. E) prevents attachment of the microtubules to the kinetochore.
Answer: D
30) The constantly changing nature of the Appalachian ground crickets ( Allonemobius fasciatus and Allonemobius socius) hybrid zone favors A) no gene flow between the two gene pools. B) little gene flow between the two gene pools. C) increased levels of gene flow between the two gene pools. D) extinction of both species as the hybrids persist.
Answer: D
30) What is the name of the functional group shown in Figure 4.4? A) carbonyl B) ketone C) aldehyde D) carboxyl E) hydroxyl
Answer: D
31) After a membrane freezes and then thaws, it often becomes leaky to solutes. The most reasonable explanation for this is that A) transport proteins become nonfunctional during freezing. B) the lipid bilayer loses its fluidity when it freezes. C) aquaporins can no longer function after freezing. D) the integrity of the lipid bilayer is broken when the membrane freezes. E) the solubility of most solutes in the cytoplasm decreases on freezing.
Answer: D
31) Measurements of the amount of DNA per nucleus were taken on a large number of cells from a growing fungus. The measured DNA levels ranged from 3 to 6 picograms per nucleus. In which stage of the cell cycle was the nucleus with 6 picograms of DNA? A) G0 B) G1 C) S D) G2 E) M
Answer: D
31) The enzyme telomerase solves the problem of replication at the ends of linear chromosomes by which method? A) adding a single 5ʹ cap structure that resists degradation by nucleases B) causing specific double strand DNA breaks that result in blunt ends on both strands C) causing linear ends of the newly replicated DNA to circularize D) adding numerous short DNA sequences such as TTAGGG, which form a hairpin turn E) adding numerous GC pairs which resist hydrolysis and maintain chromosome integrity
Answer: D
31) Which of the following contains nitrogen in addition to carbon, oxygen, and hydrogen? A) an alcohol such as ethanol B) a monosaccharide such as glucose C) a steroid such as testosterone D) an amino acid such as glycine E) a hydrocarbon such as benzene
Answer: D
32) A group of cells is assayed for DNA content immediately following mitosis and is found to have an average of 8 picograms of DNA per nucleus. Those cells would have __________ picograms at the end of the S phase and __________ picograms at the end of G 2 . A) 8; 8 B) 8; 16 C) 16; 8 D) 16; 16 E) 12; 16
Answer: D
32) How can one increase the rate of a chemical reaction? A) Increase the activation energy needed. B) Cool the reactants. C) Decrease the concentration of the reactants. D) Add a catalyst. E) Increase the entropy of the reactants.
Answer: D
32) Which of the following intermediary metabolites enters the citric acid cycle and is formed, in part, by the removal of a carbon (CO 2 ) from one molecule of pyruvate? A) lactate B) glyceraldehydes -3-phosphate C) oxaloacetate D) acetyl CoA E) citrate
Answer: D
32) Which of the following is a false statement concerning amino groups? A) They are basic in pH. B) They are found in amino acids. C) They contain nitrogen. D) They are nonpolar. E) They are components of urea.
Answer: D
33) Charles Darwin proposed a mechanism for descent with modification which stated that organisms of a particular species are adapted to their environment when they possess A) non- inheritable traits that enhance their survival in the local environment. B) non- inheritable traits that enhance their reproductive success in the local environment. C) non- inheritable traits that enhance their survival and reproductive success in the local environment. D) inheritable traits that enhance their survival and reproductive success in the local environment. E) inheritable traits that decrease their survival and reproductive success in the local environment.
Answer: D
33) The splitting of carbon dioxide to form oxygen gas and carbon compounds occurs during A) photosynthesis. B) respiration. C) both photosynthesis and respiration. D) neither photosynthesis nor respiration. E) photorespiration.
Answer: D
33) This can inhibit transcription by blocking the binding of positively acting transcription factors to the DNA: A) enhancer B) promoter C) activator D) repressor E) terminator
Answer: D
33) Which of the following statements is completely correct? A) H2CO3 is a weak acid, and NaOH is a weak base (alkali). B) H2CO3 is a strong acid, and NaOH is a strong base (alkali). C) NH3 is a weak base (alkali), and H 2CO3 is a strong acid. D) NH3 is a weak base (alkali), and HCl is a strong acid. E) NH3 is a strong base (alkali), and HCl is a weak acid.
Answer: D
34) At a specific area of a chromosome, the sequence of nucleotides below is present where the chain opens to form a replication fork: 3ʹ C C T A G G C T G C A A T C C 5ʹ An RNA primer is formed starting at the underlined T ( T) of the template. Which of the following represents the primer sequence? A) 5ʹ G C C T A G G 3ʹ B) 3ʹ G C C T A G G 5ʹ C) 5ʹ A C G T T A G G 3ʹ D) 5ʹ A C G U U A G G 3ʹ E) 5ʹ G C C U A G G 3ʹ
Answer: D
34) Imagine looking through a microscope at a squashed onion root tip. The chromosomes of many of the cells are plainly visible. In some cells, replicated chromosomes are aligned along the center (equator) of the cell. These particular cells are in which stage of mitosis? A) telophase B) prophase C) anaphase D) metaphase E) prometaphase
Answer: D
35) A carbon skeleton is covalently bonded to both an amino group and a carboxyl group. When placed in water it A) would function only as an acid because of the carboxyl group. B) would function only as a base because of the amino group. C) would function as neither an acid nor a base. D) would function as both an acid and a base. E) is impossible to determine how it would function.
Answer: D
35) Organelles other than the nucleus that contain DNA include A) ribosomes. B) mitochondria. C) chloroplasts. D) B and C only E) A, B, and C
Answer: D
35) Steroid hormones produce their effects in cells by A) activating key enzymes in metabolic pathways. B) activating translation of certain mRNAs. C) promoting the degradation of specific mRNAs. D) binding to intracellular receptors and promoting transcription of specific genes. E) promoting the formation of looped domains in certain regions of DNA.
Answer: D
35) Tallness (T) in snapdragons is dominant to dwarfness ( t), while red (R) flower color is dominant to white ( r). The heterozygous condition results in pink (Rr) flower color. A dwarf, red snapdragon is crossed with a plant homozygous for tallness and white flowers. What are the genotype and phenotype of the F 1 individuals? A) ttRr-dwarf and pink B) ttrr-dwarf and white C) TtRr-tall and red D) TtRr-tall and pink E) TTRR-tall and red
Answer: D
36) A chemist wishes to make an organic molecule less acidic. Which of the following functional groups should be added to the molecule in order to do so? A) carboxyl B) sulfhydryl C) hydroxyl D) amino E) phosphate
Answer: D
36) Carbon skeletons for amino acid biosynthesis are supplied by intermediates of the citric acid cycle. Which intermediate would supply the carbon skeleton for synthesis of a five-carbon amino acid? A) succinate B) malate C) citrate D) α-ketoglutarate E) isocitrate
Answer: D
36) The chemical reactions involved in respiration are virtually identical between prokaryotic and eukaryotic cells. In eukaryotic cells, ATP is synthesized primarily on the inner membrane of the mitochondria. Where are the corresponding reactions likely to occur in prokaryotic respiration? A) in the cytoplasm B) on the inner mitochondrial membrane C) on the endoplasmic reticulum D) on the inner plasma membrane E) on the inner nuclear envelope
Answer: D
36) Which statement best describes the evolution of pesticide resistance in a population of insects? A) Individual members of the population slowly adapt to the presence of the chemical by striving to meet the new challenge. B) All insects exposed to the insecticide begin to use a formerly silent gene to make a new enzyme that breaks down the insecticide molecules. C) Insects observe the behavior of other insects that survive pesticide application, and adjust their own behaviors to copy those of the survivors. D) Offspring of insects that are genetically resistant to the pesticide become more abundant as the susceptible insects die off.
Answer: D
4) H
10) I
D) 41.5% gray body, vestigial wings 41.5% black body, normal wings 8.5% gray body, normal wings
8.5% black body, vestigial wings
23) Three or four of the following illustrations depict different structural isomers of the organic compound with molecular formula C 6H14. For clarity, only the carbon skeletons are shown; hydrogen atoms that would be attached to the carbons have been omitted. Which one, if any, is NOT a structural isomer of this compound?
A)
24) Which of the pairs of molecular structures shown below depict enantiomers (enantiomeric forms) of the same molecule?
A)
40) Which of these evolutionary trees represents the situation described in the paragraph above (NOTE: yakuba (I) represents the island population, and yakuba (M) represents the mainland population)?
A)
52) Carbon dioxide (CO2 ) is readily soluble in water, according to the equation CO 2 + H2O → H2CO3 . Carbonic acid (H2CO3 ) is a weak acid. If CO2 is bubbled into a beaker containing pure, freshly-distilled water, which of the following graphs correctly describes the results?
A)
67) Which one of the atoms shown would be most likely to form an anion with a charge of -1?
A)
(A) Draw solid arrows to indicate the net movement of solutes into and/or out of the cell. (B) Is the solution outside the cell isotonic, hypotonic, or hypertonic? (C) Draw a dashed arrow to show the net osmotic movement of water, if any. (D) Will the artificial cell become more flaccid, more turgid, or stay the same? (E) Eventually, will the two solutions have the same or different solute concentrations?
Answer: (A)
24) Imagine that a newly discovered, recessively inherited disease is expressed only in individuals with type O blood, although the disease and blood group are independently inherited. A normal man with type A blood and a normal woman with type B blood have already had one child with the disease. The woman is now pregnant for a second time. What is the probability that the second child will also have the disease? Assume that both parents are heterozygous for the gene that causes the disease.
Answer: 1/16
37) P680+ is said to be the strongest biological oxidizing agent. Why? A) It is the receptor for the most excited electron in either photosystem. B) It is the molecule that transfers electrons to plastoquinone (Pq) of the electron transfer system. C) NADP reductase will then catalyze the shift of the electron from Fd to NADP + to reduce it to NADPH. D) This molecule results from the transfer of an electron to the primary electron acceptor of photosystem II and strongly attracts another electron. E) This molecule is found far more frequently among bacteria as well as in plants and plantlike Protists.
Answer: D
22) Karen and Steve each have a sibling with sickle-cell disease. Neither Karen nor Steve nor any of their parents have the disease, and none of them have been tested to reveal sickle-cell trait. Based on this incomplete information, calculate the probability that if this couple has a child, the child will have sickle-cell disease.
Answer: 1/9
4) A wild- type fruit fly (heterozygous for gray body color and normal wings) is mated with a black fly with vestigial wings. The offspring have the following phenotypic distribution: wild type, 778; black -vestigial, 785; black-normal, 158; gray -vestigial, 162. What is the recombination frequency between these genes for body color and wing size?
Answer: 17%
25) In tigers, a recessive allele causes an absence of fur pigmentation (a white tiger) and a cross-eyed condition. If two phenotypically normal tigers that are heterozygous at this locus are mated, what percentage of their offspring will be cross -eyed? What percentage will be white?
Answer: 25% will be cross-eyed; all of the cross-eyed offspring will also be white.
1) Garrod hypothesized that ʺinborn errors of metabolismʺ such as alkaptonuria occur because A) genes dictate the production of specific enzymes, and affected individuals have genetic defects that cause them to lack certain enzymes. B) enzymes are made of DNA, and affected individuals lack DNA polymerase. C) many metabolic enzymes use DNA as a cofactor, and affected individuals have mutations that prevent their enzymes from interacting efficiently with DNA. D) certain metabolic reactions are carried out by ribozymes, and affected individuals lack key splicing factors. E) metabolic enzymes require vitamin cofactors, and affected individuals have significant nutritional deficiencies.
Answer: A
1) In the term trace element, the modifier trace means A) the element is required in very small amounts. B) the element can be used as a label to trace atoms through an organismʹs metabolism. C) the element is very rare on Earth. D) the element enhances health but is not essential for the organismʹs long - term survival. E) the element passes rapidly through the organism.
Answer: A
1) In the yeast signal transduction pathway, after both types of mating cells have released the mating factors and the factors have bound to specific receptors on the correct cells, A) binding induces changes in the cells that lead to cell fusion. B) the cells then produce the a factor and the α factor. C) one cell nucleus binds the mating factors and produces a new nucleus in the opposite cell. D) the cell membranes fall apart, releasing the mating factors that lead to new yeast cells. E) a growth factor is secreted that stimulates mitosis in both cells.
Answer: A
1) The centromere is a region in which A) chromatids remain attached to one another until anaphase. B) metaphase chromosomes become aligned at the metaphase plate. C) chromosomes are grouped during telophase. D) the nucleus is located prior to mitosis. E) new spindle microtubules form at either end.
Answer: A
1) What is a genome? A) The complete complement of an organismʹs genes B) A specific set of polypeptides within each cell C) A specialized polymer of four different kinds of monomers D) A specific segment of DNA that is found within a prokaryotic chromosome E) An ordered display of chromosomes arranged from largest to smallest
Answer: A
1) Which gas was least abundant in Earthʹs early atmosphere, prior to 2 billion years ago? A) O2 B) CO2 C) CH4 D) H2O E) NH3
Answer: A
10) A particular triplet of bases in the template strand of DNA is 5ʹ AGT 3ʹ. The corresponding codon for the mRNA transcribed is A) 3ʹ UCA 5ʹ. B) 3ʹ UGA 5ʹ. C) 5ʹ TCA 3ʹ. D) 3ʹACU 5ʹ. E) either UCA or TCA, depending on wobble in the first base.
Answer: A
10) The ATP made during glycolysis is generated by A) substrate- level phosphorylation. B) electron transport. C) photophosphorylation. D) chemiosmosis. E) oxidation of NADH to NAD + .
Answer: A
10) What is the chromosomal system of sex determination in most species of ants and bees? A) Haploid-diploid B) X-0 C) X-X D) X-Y E) Z-W
Answer: A
37) The observation that island D. yakuba are more closely related to mainland D. yakuba than island D. yakuba are to D. santomea is best explained by proposing that D. santomea A) descended from a now -extinct, non-African fruit fly. B) arose de novo; that is, had no ancestors. C) descended from a single colony of D. yakuba , which had been introduced from elsewhere, with no subsequent colonization events. D) descended from an original colony of D. yakuba , of which there are no surviving members. The current island D. yakuba represent a second colonization event from elsewhere.
Answer: D
11) Females of one species choose mates based on song quality; females of another species choose mates on the basis of size. A) behavioral B) gametic C) habitat D) temporal E) mechanical
Answer: A
11) For most ecosystems __________ is (are) the ultimate source of energy, and energy leaves the ecosystem in the form of __________. A) sunlight; heat B) heat; light C) plants; animals D) plants; heat E) producers; consumers
Answer: A
11) In modern terminology, diversity is understood to be a result of genetic variation. Sources of variation for evolution include all of the following except A) mistakes in translation of structural genes. B) mistakes in DNA replication. C) translocations and mistakes in meiosis. D) recombination at fertilization. E) recombination by crossing over in meiosis.
Answer: A
11) Of the following, a receptor protein in a membrane that recognizes a chemical signal is most similar to A) the active site of an allosteric enzyme in the cytoplasm that binds to a specific substrate. B) RNA specifying the amino acids in a polypeptide. C) a particular metabolic pathway operating within a specific organelle. D) an enzyme with an optimum pH and temperature for activity. E) genes making up a chromosome.
Answer: A
11) RNA molecules can both carry genetic information and be catalytic. This supports the proposal that A) RNA was the first hereditary information. B) protobionts had an RNA membrane. C) RNA could make energy. D) free nucleotides would not have been necessary ingredients in the synthesis of new RNA molecules. E) RNA is a polymer of amino acids.
Answer: A
11) SRY is best described in which of the following ways? A) A gene region present on the Y chromosome that triggers male development B) A gene present on the X chromosome that triggers female development C) An autosomal gene that is required for the expression of genes on the Y chromosome D) An autosomal gene that is required for the expression of genes on the X chromosome E) Required for development, and males or females lacking the gene do not survive past early childhood
Answer: A
11) The presence of cholesterol in the plasma membranes of some animals A) enables the membrane to stay fluid more easily when cell temperature drops. B) enables the animal to remove hydrogen atoms from saturated phospholipids. C) enables the animal to add hydrogen atoms to unsaturated phospholipids. D) makes the membrane less flexible, allowing it to sustain greater pressure from within the cell. E) makes the animal more susceptible to circulatory disorders.
Answer: A
11) The term ʺhomoplasyʺ is most applicable to which of these features? A) the legless condition found in various types of extant lizards B) the 5-digit condition of human hands and bat wings C) the beta-hemoglobin genes of mice and of humans D) the fur that covers Australian moles and North American moles E) the basic skeletal features of dog forelimbs and cat forelimbs
Answer: A
12) A trend toward the decrease in the size of plants on the slopes of mountains as altitudes increase is an example of A) a cline. B) a bottleneck. C) relative fitness. D) genetic drift. E) geographic variation.
Answer: A
12) According to the fluid mosaic model of cell membranes, which of the following is a true statement about membrane phospholipids? A) They can move laterally along the plane of the membrane. B) They frequently flip- flop from one side of the membrane to the other. C) They occur in an uninterrupted bilayer, with membrane proteins restricted to the surface of the membrane. D) They are free to depart from the membrane and dissolve in the surrounding solution. E) They have hydrophilic tails in the interior of the membrane.
Answer: A
12) Cytosine makes up 38% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine? A) 12 B) 24 C) 31 D) 38 E) It cannot be determined from the information provided.
Answer: A
12) What probably accounts for the switch to DNA -based genetic systems during the evolution of life on Earth? A) DNA is chemically more stable and replicates with fewer errors (mutations) than RNA. B) Only DNA can replicate during cell division. C) RNA is too involved with translation of proteins and cannot provide multiple functions. D) DNA forms the rod-shaped chromosomes necessary for cell division. E) Replication of RNA occurs too slowly.
Answer: A
12) What would be true for the signaling system in an animal cell that lacks the ability to produce GTP? A) It would not be able to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane. B) It could activate only the epinephrine system. C) It would be able to carry out reception and transduction, but would not be able to respond to a signal. D) Only A and C are true. E) A, B, and C are true.
Answer: A
12) Which of the following is considered an open system? A) an organism B) liquid in a corked bottle C) a sealed terrarium D) food cooking in a pressure cooker
Answer: A
13) On food packages, to what does the term ʺinsoluble fiberʺ refer? A) cellulose B) polypeptides C) starch D) amylopectin E) chitin
Answer: A
13) The DNA fragments making up a genomic library are generally contained in A) recombinant plasmids of bacteria. B) recombinant viral RNA. C) individual wells. D) DNA-RNA hybrids E) radioactive eukaryotic cells
Answer: A
13) What wavelength of light in the figure is most effective in driving photosynthesis? A) 420 mm B) 475 mm C) 575 mm D) 625 mm E) 730 mm
Answer: A
13) Which of the following is one of the ways that the membranes of winter wheat are able to remain fluid when it is extremely cold? A) by increasing the percentage of unsaturated phospholipids in the membrane B) by increasing the percentage of cholesterol molecules in the membrane C) by decreasing the number of hydrophobic proteins in the membrane D) by co- transport of glucose and hydrogen E) by using active transport
Answer: A
14) Compared with the lines for chlorophyll a in the figure, where would you expect to find the lines to differ for chlorophyll b? A) The absorption spectrum line would be lowest for chlorophyll b somewhat to the right of that for chlorophyll a (500—600). B) The rate of photosynthesis line for chlorophyll b would be lowest from 600—700 nm. C) The lines for the two types of chlorophyll would be almost completely opposite. D) The lines for the two types of chlorophyll would be almost completely identical. E) The peaks of the line for absorbance of b would be shifted to the left, and for rate of photosynthesis would be shifted to the right.
Answer: A
14) Which of the following pairs are the best examples of homologous structures? A) bat wing and human hand B) owl wing and hornet wing C) porcupine quill and cactus spine D) bat forelimb and bird wing E) Australian mole and North American mole
Answer: A
15) Based on your knowledge of the polarity of water molecules, the solute molecule is most likely A) positively charged. B) negatively charged. C) without charge. D) hydrophobic. E) nonpolar.
Answer: A
15) Calico cats are female because A) a male inherits only one of the two X - linked genes controlling hair color. B) the males die during embryonic development. C) the Y chromosome has a gene blocking orange coloration. D) only females can have Barr bodies. E) multiple crossovers on the Y chromosome prevent orange pigment production.
Answer: A
15) Why does the DNA double helix have a uniform diameter? A) Purines pair with pyrimidines. B) C nucleotides pair with A nucleotides. C) Deoxyribose sugars bind with ribose sugars. D) Nucleotides bind with nucleosides. E) Nucleotides bind with nucleoside triphosphates.
Answer: A
16) Hydrophobic substances such as vegetable oil are A) nonpolar substances that repel water molecules. B) nonpolar substances that have an attraction for water molecules. C) polar substances that repel water molecules. D) polar substances that have an affinity for water. E) charged molecules that hydrogen-bond with water molecules.
Answer: A
16) In birds, sex is determined by a ZW chromosome scheme. Males are ZZ and females are ZW. A recessive lethal allele that causes death of the embryo is sometimes present on the Z chromosome in pigeons. What would be the sex ratio in the offspring of a cross between a male that is heterozygous for the lethal allele and a normal female? A) 2:1 male to female B) 1:2 male to female C) 1:1 male to female D) 4:3 male to female E) 3:1 male to female
Answer: A
16) The ʺuniversalʺ genetic code is now known to have exceptions. Evidence for this could be found if which of the following is true? A) If UGA, usually a stop codon, is found to code for an amino acid such as tryptophan (usually coded for by UGG only). B) If one stop codon, such as UGA, is found to have a different effect on translation than another stop codon, such as UAA. C) If prokaryotic organisms are able to translate a eukaryotic mRNA and produce the same polypeptide. D) If several codons are found to translate to the same amino acid, such as serine. E) If a single mRNA molecule is found to translate to more than one polypeptide when there are two or more AUG sites.
Answer: A
16) Two species of frogs belonging to the same genus occasionally mate, but the offspring fail to develop and hatch. What is the mechanism for keeping the two frog species separate? A) the postzygotic barrier called hybrid inviability B) the postzygotic barrier called hybrid breakdown C) the prezygotic barrier called hybrid sterility D) gametic isolation E) adaptation
Answer: A
16) Which of the following best describes the complete sequence of steps occurring during every cycle of PCR? 1. The primers hybridize to the target DNA. 2. The mixture is heated to a high temperature to denature the double stranded target DNA. 3. Fresh DNA polymerase is added. 4. DNA polymerase extends the primers to make a copy of the target DNA. A) 2, 1, 4 B) 1, 3, 2, 4 C) 3, 4, 1, 2 D) 3, 4, 2 E) 2, 3, 4
Answer: A
16) Which of the following is a reasonable explanation for why unsaturated fatty acids help keep any membrane more fluid at lower temperatures? A) The double bonds form kinks in the fatty acid tails, forcing adjacent lipids to be further apart. B) Unsaturated fatty acids have a higher cholesterol content and therefore more cholesterol in membranes. C) Unsaturated fatty acids permit more water in the interior of the membrane. D) The double bonds block interaction among the hydrophilic head groups of the lipids. E) The double bonds result in shorter fatty acid tails and thinner membranes.
Answer: A
17) If there are 20 chromatids in a cell at metaphase, how many chromosomes are there in each daughter cell following cytokinesis? A) 10 B) 20 C) 30 D) 40 E) 80
Answer: A
17) It became apparent to Watson and Crick after completion of their model that the DNA molecule could carry a vast amount of hereditary information in which of the following? A) sequence of bases B) phosphate-sugar backbones C) complementary pairing of bases D) side groups of nitrogenous bases E) different five-carbon sugars
Answer: A
17) Which of the life cycles is typical for animals? A) I only B) II only C) III only D) I and II E) I and III
Answer: A
18) Of the following, the best conclusion concerning the difference between the S phases for beta and gamma is that A) gamma contains more DNA than beta. B) beta and gamma contain the same amount of DNA. C) beta contains more RNA than gamma. D) gamma contains 48 times more DNA and RNA than beta. E) beta is a plant cell and gamma is an animal cell.
Answer: A
19) Electrons exist only at fixed levels of potential energy. However, if an atom absorbs sufficient energy, a possible result is that A) an electron may move to an electron shell farther out from the nucleus. B) an electron may move to an electron shell closer to the nucleus. C) the atom may become a radioactive isotope. D) the atom would become a positively charged ion, or cation. E) the atom would become a negatively charged ion, or anion.
Answer: A
19) Mendel and Morgan did not know about the structure of DNA; however, which of the following of their contributions was (were) necessary to Watson and Crick? A) the particulate nature of the hereditary material B) dominance vs. recessiveness C) sex- linkage D) genetic distance and mapping E) the usefulness of peas and Drosophila
Answer: A
19) The first cell whose entire genome was sequenced was which of the following? A) H. influenzae in 1995 B) H. sapiens in 2001 C) rice in 1955 D) tobacco mosaic virus E) HIV in 1998
Answer: A
19) Which of the following statements correctly describes geometric isomers? A) They have variations in arrangement around a double bond. B) They have an asymmetric carbon that makes them mirror images. C) They have the same chemical properties. D) They have different molecular formulas. E) Their atoms and bonds are arranged in different sequences.
Answer: A
19) Which step consists of a phosphorylation reaction in which ATP is the phosphate source?
Answer: A
2) Bird guides once listed the myrtle warbler and Audubonʹs warbler as distinct species. Recently, these birds have been classified as eastern and western forms of a single species, the yellow-rumped warbler. Which of the following pieces of evidence, if true, would be cause for this reclassification? A) The two forms interbreed often in nature, and their offspring have good survival and reproduction. B) The two forms live in similar habitats. C) The two forms have many genes in common. D) The two forms have similar food requirements. E) The two forms are very similar in coloration.
Answer: A
2) In their laboratory simulations of the early Earth, Miller and Urey observed the abiotic synthesis of A) amino acids. B) complex organic polymers. C) DNA. D) liposomes. E) genetic systems.
Answer: A
2) Muscle cells differ from nerve cells mainly because they A) express different genes. B) contain different genes. C) use different genetic codes. D) have unique ribosomes. E) have different chromosomes.
Answer: A
2) The oxygen revolution changed Earthʹs environment dramatically. Which of the following adaptations took advantage of the presence of free oxygen in the oceans and atmosphere? A) the evolution of cellular respiration, which used oxygen to help harvest energy from organic molecules B) the persistence of some animal groups in anaerobic habitats C) the evolution of photosynthetic pigments that protected early algae from the corrosive effects of oxygen D) the evolution of chloroplasts after early protists incorporated photosynthetic cyanobacteria E) the evolution of multicellular eukaryotic colonies from communities of prokaryotes
Answer: A
2) The scientific discipline concerned with naming organisms is called A) taxonomy. B) cladistics. C) binomial nomenclature. D) systematics. E) phylocode
Answer: A
2) There are 40 individuals in population 1, all of which have genotype A1A1, and there are 25 individuals in population 2, all of genotype A2A2. Assume that these populations are located far from one another and that their environmental conditions are very similar. Based on the information given here, the observed genetic variation is mostly likely an example of A) genetic drift. B) gene flow. C) disruptive selection. D) discrete variation. E) directional selection.
Answer: A
2) Vinblastine is a standard chemotherapeutic drug used to treat cancer. Because it interferes with the assembly of microtubules, its effectiveness must be related to A) disruption of mitotic spindle formation. B) inhibition of regulatory protein phosphorylation. C) suppression of cyclin production. D) myosin denaturation and inhibition of cleavage furrow formation. E) inhibition of DNA synthesis.
Answer: A
2) What is generally true of two very closely related species that have diverged from each other quite recently? A) They shared a common ancestor recently in evolutionary time. B) Genes are unable to pass from one speciesʹ gene pool to the otherʹs gene pool. C) They are unable to produce hybrid offspring upon interbreeding. D) Their reproductive isolation from each other is complete.
Answer: A
2) What is the difference between a linkage map and a physical map? A) For a linkage map, markers are spaced by recombination frequency, whereas for a physical map they are spaced by numbers of base pairs (bp). B) For a physical map, the ATCG order and sequence must be achieved, but not for the linkage map. C) For a linkage map, it is shown how each gene is linked to every other gene. D) For a physical map, the distances must be calculable in units such as nanometers. E) There is no difference between the two except in the type of pictorial representation.
Answer: A
2) When Thomas Hunt Morgan crossed his red -eyed F1 generation flies to each other, the F 2 generation included both red- and white-eyed flies. Remarkably, all the white-eyed flies were male. What was the explanation for this result? A) The gene involved is on the X chromosome. B) The gene involved is on the Y chromosome. C) The gene involved is on an autosome. D) Other male-specific factors influence eye color in flies. E) Other female-specific factors influence eye color in flies.
Answer: A
2) Which definition of evolution would have been most foreign to Charles Darwin during his lifetime? A) change in gene frequency in gene pools B) descent with modification C) the gradual change of a populationʹs heritable traits over generations D) populations becoming better adapted to their environments over the course of generations E) the appearance of new varieties and new species with the passage of time
Answer: A
2) Who proposed that membranes are a phospholipid bilayer between two layers of hydrophilic proteins? A) H. Davson and J. Danielli B) I. Langmuir C) C. Overton D) S. Singer and G. Nicolson E) E. Gorter and F. Grendel
Answer: A
20) A chemical reaction that has a positive △G is correctly described as A) endergonic. B) endothermic. C) enthalpic. D) spontaneous. E) exothermic.
Answer: A
20) Given a population that contains genetic variation, what is the correct sequence of the following events, under the influence of natural selection? 1. Well-adapted individuals leave more offspring than do poorly adapted individuals. 2. A change occurs in the environment. 3. Genetic frequencies within the population change. 4. Poorly adapted individuals have decreased survivorship. A) 2 → 4 → 1 → 3 B) 4 → 2 → 1 → 3 C) 4 → 1 → 2 → 3 D) 4 → 2 → 3 → 1 E) 2 → 4 → 3 → 1
Answer: A
20) What is it about short tandem repeat DNA that makes it useful for DNA fingerprinting? A) The number of repeats varies widely from person to person or animal to animal. B) The sequence of DNA that is repeated varies significantly from individual to individual. C) The sequence variation is acted upon differently by natural selection in different environments. D) Every racial and ethnic group has inherited different short tandem repeats.
Answer: A
20) What is the name given to viruses that are single -stranded RNA that acts as a template for DNA synthesis? A) retroviruses B) proviruses C) viroids D) bacteriophages E) lytic phages
Answer: A
20) Which structure is the site of the synthesis of proteins that may be exported from the cell? A) rough ER B) lysosomes C) plasmodesmata D) Golgi vesicles E) tight junctions
Answer: A
21) In a life cycle such as that shown in part III of Figure 13.1, if the zygoteʹs chromosome number is 10, which of the following will be true? A) The sporophyteʹs chromosome number per cell is 10 and the gametophyteʹs is 5. B) The sporophyteʹs chromosome number per cell is 5 and the gametophyteʹs is 10. C) The sporophyte and gametophyte each have 10 chromosomes per cell. D) The sporophyte and gametophyte each have 5 chromosomes per cell. E) The sporophyte and gametophyte each have 20 chromosomes per cell.
Answer: A
21) Which of the following mechanisms is (are) used to coordinately control the expression of multiple, related genes in eukaryotic cells? A) organization of the genes into clusters, with local chromatin structures influencing the expression of all the genes at once B) each of the genes sharing a common control element, allowing several activators to turn on their transcription, regardless of their location in the genome C) organizing the genes into large operons, allowing them to be transcribed as a single unit D) a single repressor able to turn off several related genes E) environmental signals that enter the cell and bind directly to their promoters
Answer: A
22) Research indicates that Albuterol, a drug used to relax bronchial muscles, improving airflow and thus offering relief from asthma, consists only of one enantiomer, the R - form. Why is it important for this drug to consist of only one enantiomeric form, rather than a mixture of enantiomers? A) Different enantiomers may have different or opposite physiological effects. B) It is impossible to synthesize mixtures of enantiomers. C) It is much less expensive to synthesize one enantiomer at a time. D) Albuterol is an example of a compound for which only one enantiomer exists. E) Only the R- form of Albuterol has been studied; until more information is available, physicians prefer to use the pure R - form.
Answer: A
22) The fact that the outer membrane of the nuclear envelope has bound ribosomes allows one to most reliably conclude that A) at least some of the proteins that function in the nuclear envelope are made by the ribosomes on the nuclear envelope. B) the nuclear envelope is not part of the endomembrane system. C) the nuclear envelope is physically continuous with the endoplasmic reticulum. D) small vesicles from the Golgi fuse with the nuclear envelope. E) nuclear pore complexes contain proteins.
Answer: A
22) Which of the following can be effective in preventing viral infection in humans? A) getting vaccinated B) taking nucleoside analogs that inhibit transcription C) taking antibiotics D) applying antiseptics E) taking vitamins
Answer: A
37) These Protists are intermediate in what sense? A) They reproduce by binary fission in their early stages of development and by mitosis when they are mature. B) They never coil up their chromosomes when they are dividing. C) They use mitotic division but only have circular chromosomes. D) They maintain a nuclear envelope during division. E) None of them form spindles.
Answer: D
37) Through time, the lineage that led to modern whales shows a change from four - limbed land animals to aquatic animals with two limbs that function as flippers. This change is best explained by A) natural philosophy. B) creationism. C) the hierarchy of the biological organization of life. D) natural selection. E) feedback inhibition.
Answer: D
23) How would one explain a testcross involving F 1 dihybrid flies in which more parental- type offspring than recombinant- type offspring are produced? A) The two genes are linked. B) The two genes are linked but on different chromosomes. C) Recombination did not occur in the cell during meiosis. D) The testcross was improperly performed. E) Both of the characters are controlled by more than one gene.
Answer: A
23) Which of these makes determining the evolutionary relatedness of different species based on the amino acid sequence of homologous proteins generally less accurate than determinations of relatedness based on the nucleotide sequences of homologous genes? A) Silent mutations B) Gene duplications C) Translocation events that change gene sequences D) Crossing-over E) Independent assortment
Answer: A
23) Which species are extinct? A) A and E B) A and B C) C and D D) D and E E) cannot be determined from the information provided
Answer: A
24) What does the chemiosmotic process in chloroplasts involve? A) establishment of a proton gradient B) diffusion of electrons through the thylakoid membrane C) reduction of water to produce ATP energy D) movement of water by osmosis into the thylakoid space from the stroma E) formation of glucose, using carbon dioxide, NADPH, and ATP
Answer: A
24) Which of the following statements is false for the class of biological molecules known as lipids? A) They are soluble in water. B) They are an important constituent of cell membranes. C) They contain more energy than proteins and carbohydrates. D) They are not true polymers. E) They contain waxes and steroids.
Answer: A
25) In comparing the genomes of humans and those of other higher primates, it is seen that humans have a large metacentric pair we call chromosome #2 among our 46 chromosomes, while the other primates of this group have 48 chromosomes and any pair like the human #2 pair is not present; instead the primate groups each have two pairs of midsize acrocentric chromosomes. What is the most likely explanation? A) The ancestral organism had 48 chromosomes and at some point a centric fusion event occurred and provided some selective advantage. B) The ancestral organism had 46 chromosomes, but primates evolved when one of the pairs broke in half. C) At some point in evolution, human ancestors and primate ancestors were able to mate and produce fertile offspring, making a new species. D) Chromosome breakage results in additional centromeres being made in order for meiosis to proceed successfully. E) Transposable elements transferred significantly large segments of the chromosomes to new locations.
Answer: A
25) Suppose the interior of the thylakoids of isolated chloroplasts were made acidic and then transferred in the dark to a pH -8 solution. What would be likely to happen? A) The isolated chloroplasts will make ATP. B) The Calvin cycle will be activated. C) Cyclic photophosphorylation will occur. D) Only A and B will occur. E) A, B, and C will occur.
Answer: A
25) Taxol is an anticancer drug extracted from the Pacific yew tree. In animal cells, taxol disrupts microtubule formation by binding to microtubules and accelerating their assembly from the protein precursor, tubulin. Surprisingly, this stops mitosis. Specifically, taxol must affect A) the fibers of the mitotic spindle. B) anaphase. C) formation of the centrioles. D) chromatid assembly. E) the S phase of the cell cycle.
Answer: A
25) The difference between geographic isolation and habitat differentiation is the A) relative locations of two populations as speciation occurs. B) speed (tempo) at which two populations undergo speciation. C) amount of genetic variation that occurs among two gene pools as speciation occurs. D) identity of the phylogenetic kingdom or domain in which these phenomena occur. E) the ploidy of the two populations as speciation occurs.
Answer: A
25) What does a frequency of recombination of 50% indicate? A) The two genes are likely to be located on different chromosomes. B) All of the offspring have combinations of traits that match one of the two parents. C) The genes are located on sex chromosomes. D) Abnormal meiosis has occurred. E) Independent assortment is hindered.
Answer: A
25) Which drawing is of an atom with the atomic number of 6?
Answer: A
25) Which of the following statements is an inference of natural selection? A) Subsequent generations of a population should have greater proportions of individuals that possess traits better suited for success in unchanging environments. B) An individual organism undergoes evolution over the course of its lifetime. C) Habitats do not generally have unlimited resources. D) Natural populations tend to reproduce to their full biological potential. E) Some of the variation that exists among individuals in a population is genetic.
Answer: A
26) In general, a signal transmitted via phosphorylation of a series of proteins A) brings a conformational change to each protein. B) requires binding of a hormone to a cytosol receptor. C) cannot occur in yeasts because they lack protein phosphatases. D) requires phosphorylase activity. E) allows target cells to change their shape and therefore their activity.
Answer: A
26) Which of the following must exist in a population before natural selection can act upon that population? A) Genetic variation among individuals B) Variation among individuals caused by environmental factors C) Sexual reproduction D) B and C only E) A, B, and C
Answer: A
28) A geneticist introduces a transgene into yeast cells and isolates five independent cell lines in which the transgene has integrated into the yeast genome. In four of the lines, the transgene is expressed strongly, but in the fifth there is no expression at all. Which is a likely explanation for the lack of transgene expression in the fifth cell line? A) A transgene integrated into a heterochromatic region of the genome. B) A transgene integrated into a euchromatic region of the genome. C) The transgene was mutated during the process of integration into the host cell genome. D) The host cell lacks the enzymes necessary to express the transgene. E) A transgene integrated into a region of the genome characterized by high histone acetylation.
Answer: A
28) The difference between vertical and horizontal transmission of plant viruses is that A) vertical transmission is transmission of a virus from a parent plant to its progeny, and horizontal transmission is one plant spreading the virus to another plant. B) vertical transmission is the spread of viruses from upper leaves to lower leaves of the plant, and horizontal transmission is the spread of a virus among leaves at the same general level. C) vertical transmission is the spread of viruses from trees and tall plants to bushes and other smaller plants, and horizontal transmission is the spread of viruses among plants of similar size. D) vertical transmission is the transfer of DNA from one type of plant virus to another, and horizontal transmission is the exchange of DNA between two plant viruses of the same type. E) vertical transmission is the transfer of DNA from a plant of one species to a plant of a different species, and horizontal transmission is the spread of viruses among plants of the same species.
Answer: A
28) What is the reason that linked genes are inherited together? A) They are located close together on the same chromosome. B) The number of genes in a cell is greater than the number of chromosomes. C) Chromosomes are unbreakable. D) Alleles are paired together during meiosis. E) Genes align that way during metaphase I of meiosis.
Answer: A
28) When does the synaptonemal complex disappear? A) Late prophase of meiosis I B) During fertilization or fusion of gametes C) Early anaphase of meiosis I D) Mid-prophase of meiosis II E) Late metaphase of meiosis II
Answer: A
28) Which of the following is not true of all horizontally oriented phylogenetic trees, where time advances to the right? A) Each branch point represents a point in absolute time. B) Organisms represented at the base of such trees are ancestral to those represented at higher levels. C) The more branch points that occur between two taxa, the more divergent their DNA sequences should be. D) The common ancestor represented by the rightmost branch point existed more recently in time than the common ancestors represented at branch points located to the left. E) The more branch points there are, the more taxa are likely to be represented.
Answer: A
29) The molecular weight of water is 18 daltons. What is the molarity of 1 liter of pure water? A) 55.6M B) 18M C) 37M D) 0.66M E) 1.0M
Answer: A
3) A mutation results in a defective enzyme A. Which of the following would be a consequence of that mutation? A) an accumulation of A and no production of B and C B) an accumulation of A and B and no production of C C) an accumulation of B and no production of A and C D) an accumulation of B and C and no production of A E) an accumulation of C and no production of A and B
Answer: A
3) A particular cell has half as much DNA as some other cells in a mitotically active tissue. The cell in question is most likely in A) G1 B) G2 . C) prophase. D) metaphase. E) anaphase.
Answer: A
3) One of the characteristics of retrotransposons is that A) they code for an enzyme that synthesizes DNA using an RNA template. B) they are found only in animal cells. C) they generally move by a cut -and-paste mechanism. D) they contribute a significant portion of the genetic variability seen within a population of gametes. E) their amplification is dependent on a retrovirus.
Answer: A
3) The activation of receptor tyrosine kinases is characterized by A) dimerization and phosphorylation. B) IP3 binding. C) a phosphorylation cascade. D) GTP hydrolysis. E) channel protein shape change.
Answer: A
3) The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are the α form. Which of the following could amylase break down? A) glycogen, starch, and amylopectin B) glycogen and cellulose C) cellulose and chitin D) starch and chitin E) starch, amylopectin, and cellulose
Answer: A
3) What was the prevailing notion prior to the time of Lyell and Darwin? A) Earth is a few thousand years old, and populations are unchanging. B) Earth is a few thousand years old, and populations gradually change. C) Earth is millions of years old, and populations rapidly change. D) Earth is millions of years old, and populations are unchanging. E) Earth is millions of years old, and populations gradually change.
Answer: A
3) Which of the following factors would tend to increase membrane fluidity? A) a greater proportion of unsaturated phospholipids B) a greater proportion of saturated phospholipids C) a lower temperature D) a relatively high protein content in the membrane E) a greater proportion of relatively large glycolipids compared with lipids having smaller molecular masses
Answer: A
3) Which of the following is a statement of the first law of thermodynamics? A) Energy cannot be created or destroyed. B) The entropy of the universe is decreasing. C) The entropy of the universe is constant. D) Kinetic energy is stored energy that results from the specific arrangement of matter. E) Energy cannot be transferred or transformed.
Answer: A
3) Which of the following is not an observation or inference on which Darwinʹs theory of natural selection is based? A) Poorly adapted individuals never produce offspring. B) There is heritable variation among individuals. C) Because of overproduction of offspring, there is competition for limited resources. D) Individuals whose inherited characteristics best fit them to the environment will generally produce more offspring. E) A population can become adapted to its environment.
Answer: A
30) Large organic molecules are usually assembled by polymerization of a few kinds of simple subunits. Which of the following is an exception to this statement? A) a steroid B) cellulose C) DNA D) an enzyme E) a contractile protein
Answer: A
30) Which of the following modifications is least likely to alter the rate at which a DNA fragment moves through a gel during electrophoresis? A) altering the nucleotide sequence of the DNA fragment B) methylating the cytosine bases within the DNA fragment C) increasing the length of the DNA fragment D) decreasing the length of the DNA fragment E) neutralizing the negative charges within the DNA fragment
Answer: A
31) A transcription unit that is 8,000 nucleotides long may use 1,200 nucleotides to make a protein consisting of approximately 400 amino acids. This is best explained by the fact that A) many noncoding stretches of nucleotides are present in mRNA. B) there is redundancy and ambiguity in the genetic code. C) many nucleotides are needed to code for each amino acid. D) nucleotides break off and are lost during the transcription process. E) there are termination exons near the beginning of mRNA.
Answer: A
31) DNA fragments from a gel are transferred to a nitrocellulose paper during the procedure called Southern blotting. What is the purpose of transferring the DNA from a gel to a nitrocellulose paper? A) to attach the DNA fragments to a permanent substrate B) to separate the two complementary DNA strands C) to transfer only the DNA that is of interest D) to prepare the DNA for digestion with restriction enzymes E) to separate out the PCRs
Answer: A
31) Drosophila (fruit flies) usually have long wings (+ ) but mutations in two different genes can result in bent wings (bt) or vestigial wings (vg). If a homozygous bent wing fly is mated with a homozygous vestigial wing fly, which of the following offspring would you expect? A) All +bt +vg heterozygotes B) 1/2 bent and 1/2 vestigial flies C) All homozygous + flies D) 3/4 bent to 1/4 vestigial ratio E) 1/2 bent and vestigial to 1/2 normal
Answer: A
31) The toxin of Vibrio cholerae causes profuse diarrhea because it A) modifies a G protein involved in regulating salt and water secretion. B) decreases the cytosolic concentration of calcium ions, making the cells hypotonic to the intestinal cells. C) binds with adenylyl cyclase and triggers the formation of cAMP. D) signals inositol trisphosphate to become a second messenger for the release of calcium. E) modifies calmodulin and activates a cascade of protein kinases.
Answer: A
31) Which of the following statements is (are) true about enzyme-catalyzed reactions? A) The reaction is faster than the same reaction in the absence of the enzyme. B) The free energy change of the reaction is opposite from the reaction in the absence of the enzyme. C) The reaction always goes in the direction toward chemical equilibrium. D) A and B only E) A, B, and C
Answer: A
32) Reduction of NADP+ occurs during A) photosynthesis. B) respiration. C) both photosynthesis and respiration. D) neither photosynthesis nor respiration. E) photorespiration.
Answer: A
32) Which of the following happens at the conclusion of meiosis I? A) Homologous chromosomes are separated. B) The chromosome number per cell is conserved. C) Sister chromatids are separated. D) Four daughter cells are formed. E) The sperm cells elongate to form a head and a tail end.
Answer: A
32) Which of the following would likely move through the lipid bilayer of a plasma membrane most rapidly? A) CO2 B) an amino acid C) glucose D) K+ E) starch
Answer: A
32) Which of these should decline in hybrid zones where reinforcement is occurring? A) gene flow between distinct gene pools B) speciation C) the genetic distinctness of two gene pools D) mutation rate E) hybrid sterility
Answer: A
33) Introns are significant to biological evolution because A) their presence allows exons to be shuffled. B) they protect the mRNA from degeneration. C) they are translated into essential amino acids. D) they maintain the genetic code by preventing incorrect DNA base pairings. E) they correct enzymatic alterations of DNA bases.
Answer: A
33) Which of the following most likely would be an immediate result of growth factor binding to its receptor? A) protein kinase activity B) adenylyl cyclase activity C) GTPase activity D) protein phosphatase activity E) phosphorylase activity
Answer: A
34) How many carbon atoms are fed into the citric acid cycle as a result of the oxidation of one molecule of pyruvate? A) 2 B) 4 C) 6 D) 8 E) 10
Answer: A
34) Map units on a linkage map cannot be relied upon to calculate physical distances on a chromosome for which of the following reasons? A) The frequency of crossing over varies along the length of the chromosome. B) The relationship between recombination frequency and map units is different in every individual. C) Physical distances between genes change during the course of the cell cycle. D) The gene order on the chromosomes is slightly different in every individual. E) Linkage map distances are identical between males and females.
Answer: A
35) Starting with one molecule of isocitrate and ending with fumarate, what is the maximum number of ATP molecules that could be made through substrate- level phosphorylation? A) 1 B) 2 C) 11 D) 12 E) 24
Answer: A
35) The bonding of two amino acid molecules to form a larger molecule requires A) the release of a water molecule. B) the release of a carbon dioxide molecule. C) the addition of a nitrogen atom. D) the addition of a water molecule. E) both B and C
Answer: A
36) Which of these is closest to the allele frequency in the founding population? A) 0.1 a, 0.9 A B) 0.2 a, 0.8 A C) 0.5 a, 0.5 A D) 0.8 a, 0.2 A E) 0.4 a, 0.6 A
Answer: A
37) If one assumes that Hardy -Weinberg equilibrium applies to the population of colonists on this planet, about how many people will have attached earlobes when the planetʹs population reaches 10,000? A) 100 B) 400 C) 800 D) 1,000 E) 10,000
Answer: A
37) Which of these observations fails to support the endosymbiotic theory for the origin of eukaryotic cells? A) the existence of structural and molecular differences between the plasma membranes of prokaryotes and the internal membranes of mitochondria and chloroplasts B) the existence of size differences between the cytosolic ribosomes of eukaryotes and the ribosomes within mitochondria and chloroplasts C) the existence of size differences between some prokaryotic cells and mitochondria D) the existence of rRNA sequence differences between the cytosolic ribosomes of eukaryotes and the ribosomes within mitochondria and chloroplasts
Answer: A
37) Which was developed by a British researcher and causes DNA sequences to be transferred to a membrane and identified with a probe? A) Southern blotting B) Northern blotting C) Western blotting D) Eastern blotting E) RT-PCR
Answer: A
38) Fluorine has an atomic number of 9 and a mass number of 19. How many electrons are needed to complete the valence shell of a fluorine atom? A) 1 B) 3 C) 5 D) 7 E) 9
Answer: A
38) Which of the following are capable of converting light energy to chemical energy? A) chloroplasts B) mitochondria C) leucoplasts D) peroxisomes E) Golgi bodies
Answer: A
38) Which of the following solutions has the greatest concentration of hydrogen ions [H + ]? A) gastric juice at pH 2 B) vinegar at pH 3 C) tomato juice at pH 4 D) black coffee at pH 5 E) household bleach at pH 12
Answer: A
38) You briefly expose bacteria undergoing DNA replication to radioactively labeled nucleotides. When you centrifuge the DNA isolated from the bacteria, the DNA separates into two classes. One class of labeled DNA includes very large molecules (thousands or even millions of nucleotides long), and the other includes short stretches of DNA (several hundred to a few thousand nucleotides in length). These two classes of DNA probably represent A) leading strands and Okazaki fragments. B) lagging strands and Okazaki fragments. C) Okazaki fragments and RNA primers. D) leading strands and RNA primers. E) RNA primers and mitochondrial DNA.
Answer: A
39) A cross between a true-breeding sharp-spined cactus and a spineless cactus would produce A) all sharp-spined progeny. B) 50% sharp-spined, 50% dull-spined progeny. C) 25% sharp-spined, 50% dull-spined, 25% spineless progeny D) all spineless progeny. E) It is impossible to determine the phenotypes of the progeny.
Answer: A
39) Cyclic electron flow may be photoprotective (protective to light - induced damage). Which of the following experiments could provide information on this phenomenon? A) using mutated organisms that can grow but that cannot carry out cyclic flow of electrons and compare their abilities to photosynthesize in different light intensities B) using plants that can carry out both linear and cyclic electron flow, or only one or another of thee processes, and measuring their light absorbance C) using bacteria that have only cyclic flow and look for their frequency of mutation damage D) using bacteria with only cyclic flow and measuring the number and types of photosynthetic pigments they have in their membranes E) using plants with only photosystem I operative and measure how much damage occurs at different wavelengths.
Answer: A
39) Cyclic electron flow may be photoprotective (protective to light - induced damage). Which of the following experiments could provide information on this phenomenon? A) using mutated organisms that can grow but that cannot carry out cyclic flow of electrons and compare their abilities to photosynthesize in different light intensities B) using plants that can carry out both linear and cyclic electron flow, or only one or another of thee processes, and measuring their light absorbance C) using bacteria that have only cyclic flow and look for their frequency of mutation damage D) using bacteria with only cyclic flow and measuring the number and types of photosynthetic pigments they have in their membranes E) using plants with only photosystem I operative and measure how much damage occurs at different wavelengths.
Answer: A
39) The snowball Earth hypothesis provides a possible explanation for the A) diversification of animals during the late Proterozoic. B) oxygenation of Earthʹs seas and atmosphere. C) colonization of land by plants and fungi. D) origin of O2-releasing photosynthesis. E) existence of prokaryotes around hydrothermal vents on the ocean floor.
Answer: A
4) During a study session about evolution, one of your fellow students remarks, ʺThe giraffe stretched its neck while reaching for higher leaves; its offspring inherited longer necks as a result.ʺ Which statement is most likely to be helpful in correcting this studentʹs misconception? A) Characteristics acquired during an organismʹs life are generally not passed on through genes. B) Spontaneous mutations can result in the appearance of new traits. C) Only favorable adaptations have survival value. D) Disuse of an organ may lead to its eventual disappearance. E) Overproduction of offspring leads to a struggle for survival.
Answer: A
4) For this pair of items, choose the option that best describes their relationship. (A) The probability that amino acids with nonpolar side chains are hydrophobic. (B) The probability that amino acids with side chains containing a carboxyl group are hydrophobic. A) Item (A) is greater than item (B). B) Item (A) is less than item (B). C) Item (A) is exactly or very approximately equal to item (B). D) Item (A) may stand in more than one of the above relations to item (B).
Answer: A
4) How does a bacterial cell protect its own DNA from restriction enzymes? A) adding methyl groups to adenines and cytosines B) using DNA ligase to seal the bacterial DNA into a closed circle C) adding histones to protect the double-stranded DNA D) forming ʺsticky endsʺ of bacterial DNA to prevent the enzyme from attaching E) reinforcing the bacterial DNA structure with covalent phosphodiester bonds
Answer: A
4) If an enzyme solution is saturated with substrate, the most effective way to obtain a faster yield of products is to A) add more of the enzyme. B) heat the solution to 90°C. C) add more substrate. D) add an allosteric inhibitor. E) add a noncompetitive inhibitor.
Answer: A
4) If there are 20 chromatids in a cell, how many centromeres are there? A) 10 B) 20 C) 30 D) 40 E) 80
Answer: A
4) Meiosis II is similar to mitosis in that A) sister chromatids separate during anaphase. B) DNA replicates before the division. C) the daughter cells are diploid. D) homologous chromosomes synapse. E) the chromosome number is reduced.
Answer: A
4) One of the following people set up a closed system to mimic Earthʹs early atmosphere and discharged electrical sparks through it. A variety of organic compounds common in organisms were formed. Who did this? A) Stanley Miller B) Jakob Berzelius C) Friedrich Wohler D) Hermann Kolbe E) August Kekulé
Answer: A
4) Paracrine signaling A) involves secreting cells acting on nearby target cells by discharging a local regulator into the extracellular fluid. B) requires nerve cells to release a neurotransmitter into the synapse. C) occurs only in paracrine yeast cells. D) has been found in plants but not animals. E) involves mating factors attaching to target cells and causing production of new paracrine cells.
Answer: A
4) The F1 offspring of Mendelʹs classic pea cross always looked like one of the two parental varieties because A) one phenotype was completely dominant over another. B) each allele affected phenotypic expression. C) the traits blended together during fertilization. D) no genes interacted to produce the parental phenotype. E) different genes interacted to produce the parental phenotype.
Answer: A
4) The functioning of enhancers is an example of A) transcriptional control of gene expression. B) a post- transcriptional mechanism for editing mRNA. C) the stimulation of translation by initiation factors. D) post- translational control that activates certain proteins. E) a eukaryotic equivalent of prokaryotic promoter functioning.
Answer: A
4) The host range of a virus is determined by A) the proteins on its surface and that of the host. B) whether its nucleic acid is DNA or RNA. C) the proteins in the hostʹs cytoplasm. D) the enzymes produced by the virus before it infects the cell. E) the enzymes carried by the virus.
Answer: A
4) Where does the Calvin cycle take place? A) stroma of the chloroplast B) thylakoid membrane C) cytoplasm surrounding the chloroplast D) chlorophyll molecule E) outer membrane of the chloroplast
Answer: A
4) Which of the following is not true of RNA processing? A) Exons are cut out before mRNA leaves the nucleus. B) Nucleotides may be added at both ends of the RNA. C) Ribozymes may function in RNA splicing. D) RNA splicing can be catalyzed by spliceosomes. E) A primary transcript is often much longer than the final RNA molecule that leaves the nucleus.
Answer: A
4) Which species concept is currently most popular among most biologists? A) phylogenetic B) ecological C) biological D) morphological
Answer: A
40) If two continental land masses converge and are united, then the collision should cause A) a net loss of intertidal zone and coastal habitat. B) the extinction of any species adapted to intertidal and coastal habitats. C) an overall decrease in the surface area located in the continental interior. D) a decrease in climatic extremes in the interior of the new super -continent. E) the maintenance of the previously existing ocean currents and wind patterns.
Answer: A
40) The mitochondrion, like the nucleus, has two or more membrane layers. How is the innermost of these layers different from that of the nucleus? A) The inner mitochondrial membrane is highly folded. B) The two membranes are biochemically very different. C) The space between the two layers of the nuclear membrane is larger. D) The inner membrane of the mitochondrion is separated out into thylakoids. E) The inner mitochondrial membrane is devoid of nearly all proteins.
Answer: A
40) Which of the following separates the DNA strands during replication? A) helicase B) DNA polymerase III C) ligase D) DNA polymerase I E) primase
Answer: A
40) Which sample of DNA might be from a nerve cell arrested in G 0 of the cell cycle? A) I B) II C) III D) Either I or II E) Either II or III
Answer: A
42) A young animal has never had much energy. He is brought to a veterinarian for help and is sent to the animal hospital for some tests. There they discover his mitochondria can use only fatty acids and amino acids for respiration, and his cells produce more lactate than normal. Of the following, which is the best explanation of his condition? A) His mitochondria lack the transport protein that moves pyruvate across the outer mitochondrial membrane. B) His cells cannot move NADH from glycolysis into the mitochondria. C) His cells contain something that inhibits oxygen use in his mitochondria. D) His cells lack the enzyme in glycolysis that forms pyruvate. E) His cells have a defective electron transport chain, so glucose goes to lactate instead of to acetyl CoA.
Answer: A
42) Which of the following statements best represents the relationships between the light reactions and the Calvin cycle? A) The light reactions provide ATP and NADPH to the Calvin cycle, and the cycle returns ADP, Pi, and NADP+ to the light reactions. B) The light reactions provide ATP and NADPH to the carbon fixation step of the Calvin cycle, and the cycle provides water and electrons to the light reactions. C) The light reactions supply the Calvin cycle with CO 2 to produce sugars, and the Calvin cycle supplies the light reactions with sugars to produce ATP. D) The light reactions provide the Calvin cycle with oxygen for electron flow, and the Calvin cycle provides the light reactions with water to split. E) There is no relationship between the light reactions and the Calvin cycle.
Answer: A
42) You are maintaining a small population of fruit flies in the laboratory by transferring the flies to a new culture bottle after each generation. After several generations, you notice that the viability of the flies has decreased greatly. Recognizing that small population size is likely to be linked to decreased viability, the best way to reverse this trend is to A) cross your flies with flies from another lab. B) reduce the number of flies that you transfer at each generation. C) transfer only the largest flies. D) change the temperature at which you rear the flies. E) shock the flies with a brief treatment of heat or cold to make them more hardy.
Answer: A
43) The difference between ATP and the nucleoside triphosphates used during DNA synthesis is that A) the nucleoside triphosphates have the sugar deoxyribose; ATP has the sugar ribose. B) the nucleoside triphosphates have two phosphate groups; ATP has three phosphate groups. C) ATP contains three high -energy bonds; the nucleoside triphosphates have two. D) ATP is found only in human cells; the nucleoside triphosphates are found in all animal and plant cells. E) triphosphate monomers are active in the nucleoside triphosphates, but not in ATP.
Answer: A
43) Which of the following is most likely to have a small protein called ubiquitin attached to it? A) a cyclin that usually acts in G1, now that the cell is in G2 B) a cell surface protein that requires transport from the ER C) an mRNA that is leaving the nucleus to be translated D) a regulatory protein that requires sugar residues to be attached E) an mRNA produced by an egg cell that will be retained until after fertilization
Answer: A
38) If a pharmaceutical company wished to design a drug to maintain low blood sugar levels, one approach might be to A) design a compound that mimics epinephrine and can bind to the epinephrine receptor. B) design a compound that stimulates cAMP production in liver cells. C) design a compound to stimulate G protein activity in liver cells. D) design a compound that increases phosphodiesterase activity. E) All of the above are possible approaches.
Answer: D
39) A cell has the following molecules and structures: enzymes, DNA, ribosomes, plasma membrane, and mitochondria. It could be a cell from A) a bacterium. B) an animal, but not a plant. C) a plant, but not an animal. D) a plant or an animal. E) any kind of organism.
Answer: D
44) A phenotypically normal prospective couple seeks genetic counseling because the man knows that he has a translocation of a portion of his chromosome 4 that has been exchanged with a portion of his chromosome 12. Although he is normal because his translocation is balanced, he and his wife want to know the probability that his sperm will be abnormal. What is your prognosis regarding his sperm? A) 1/4 will be normal, 1/4 with the translocation, 1/2 with duplications and deletions. B) All will carry the same translocation as the father. C) None will carry the translocation since abnormal sperm will die. D) His sperm will be sterile and the couple might consider adoption. E) 1/2 will be normal and the rest with the fatherʹs translocation.
Answer: A
44) The leading and the lagging strands differ in that A) the leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction. B) the leading strand is synthesized by adding nucleotides to the 3ʹ end of the growing strand, and the lagging strand is synthesized by adding nucleotides to the 5ʹ end. C) the lagging strand is synthesized continuously, whereas the leading strand is synthesized in short fragments that are ultimately stitched together. D) the leading strand is synthesized at twice the rate of the lagging strand.
Answer: A
44) The phenomenon in which RNA molecules in a cell are destroyed if they have a sequence complementary to an introduced double-stranded RNA is called A) RNA interference. B) RNA obstruction. C) RNA blocking. D) RNA targeting. E) RNA disposal.
Answer: A
45) Nitrogen (N) is much more electronegative than hydrogen (H). Which of the following statements is correct about the atoms in ammonia (NH 3 )? A) Each hydrogen atom has a partial positive charge. B) The nitrogen atom has a strong positive charge. C) Each hydrogen atom has a slight negative charge. D) The nitrogen atom has a partial positive charge. E) There are covalent bonds between the hydrogen atoms.
Answer: A
45) The description above illustrates which of the following? A) Just because a drug acts on one type of receptor does not mean that it will act on another type. B) Beta blockers can be used effectively on any type of muscle. C) Beta adrenergic receptors must be in the cytosol if they are going to influence contraction and relaxation. D) The chemical structures of the beta 1 and beta 2 receptors must have the same active sites.
Answer: A
46) If an organism is diploid and a certain gene found in the organism has 18 known alleles (variants), then any given organism of that species can/must have which of the following? A) At most, 2 alleles for that gene B) Up to 18 chromosomes with that gene C) Up to 18 genes for that trait D) A haploid number of 9 chromosomes E) Up to, but not more than, 18 different traits
Answer: A
46) Which of the following best describes siRNA? A) a short double-stranded RNA, one of whose strands can complement and inactivate a sequence of mRNA B) a single-stranded RNA that can, where it has internal complementary base pairs, fold into cloverleaf patterns C) a double-stranded RNA that is formed by cleavage of hairpin loops in a larger precursor D) a portion of rRNA that allows it to bind to several ribosomal proteins in forming large or small subunits E) a molecule, known as Dicer, that can degrade other mRNA sequences
Answer: A
46) Which of the following is released by platelets in the vicinity of an injury? A) PDGF B) MPF C) protein kinase D) cyclin E) Cdk
Answer: A
46) Which of the following would be a position held by an adherent of the punctuated equilibrium theory? A) A new species forms most of its unique features as it comes into existence and then changes little for the duration of its existence. B) One should expect to find many transitional fossils left by organisms in the process of forming new species. C) Given enough time, most existing species will gradually evolve into new species. D) Natural selection is unimportant as a mechanism of evolution.
Answer: A
47) If both children are of blood group MM, which of the following is possible? A) Each parent is either M or MN. B) Each parent must be type M. C) Both children are heterozygous for this gene. D) Neither parent can have the N allele. E) The MN blood group is recessive to the ABO blood group.
Answer: A
47) One of the buffers that contribute to pH stability in human blood is carbonic acid H 2CO3 . Carbonic acid is a weak acid that when placed in an aqueous solution dissociates into a bicarbonate ion (HCO3- ) and a hydrogen ion (H+ ). Thus, H2CO3 ↔ HCO3- + H+ If the pH of the blood increases, one would expect A) a decrease in the concentration of H2CO3 and an increase in the concentration of H2O. B) an increase in the concentration of H2CO3 and a decrease in the concentration of H2O. C) a decrease in the concentration of HCO 3- and an increase in the concentration of H2O. D) an increase in the concentration of HCO 3- and a decrease in the concentration of H2O. E) a decrease in the concentration of HCO 3- and an increase in the concentration of both H2CO3 and H2O.
Answer: A
47) What is the function of topoisomerase? A) relieving strain in the DNA ahead of the replication fork B) elongation of new DNA at a replication fork by addition of nucleotides to the existing chain C) the addition of methyl groups to bases of DNA D) unwinding of the double helix E) stabilizing single-stranded DNA at the replication fork
Answer: A
47) What is the purpose of using malonic acid in this experiment? A) It is a competitive inhibitor. B) It blocks the binding of fumarate. C) It is a noncompetitive inhibitor. D) It is able to bind to succinate. E) It replaces the usual enzyme.
Answer: A
48) A covalent bond is likely to be polar when A) one of the atoms sharing electrons is much more electronegative than the other atom. B) the two atoms sharing electrons are equally electronegative. C) the two atoms sharing electrons are of the same element. D) it is between two atoms that are both very strong electron acceptors. E) the two atoms sharing electrons are different elements.
Answer: A
48) A researcher is using adult stem cells and comparing them to other adult cells from the same tissue. Which of the following is a likely finding? A) The cells from the two sources exhibit different patterns of DNA methylation. B) Adult stem cells have more DNA nucleotides than their counterparts. C) The two kinds of cells have virtually identical gene expression patterns in microarrays. D) The non-stem cells have fewer repressed genes. E) The non-stem cells have lost the promoters for more genes.
Answer: A
48) Dicynodonts survived the Permian extinction and, therefore, existed during both the A) Paleozoic and Mesozoic eras. B) Proterozoic and Archaean eons. C) Proterozoic and Phanerozoic eons. D) Mesozoic and Cenozoic eras. E) Carboniferous and Permian periods.
Answer: A
48) Produces NADPH A) light reactions alone B) the Calvin cycle alone C) both the light reactions and the Calvin cycle D) neither the light reactions nor the Calvin cycle E) occurs in the chloroplast but is not part of photosynthesis
Answer: A
48) The outcome of the conflict between bacteria and bacteriophage at any point in time results from A) frequency-dependent selection. B) evolutionary imbalance. C) heterozygote advantage. D) neutral variation. E) genetic variation being preserved by diploidy.
Answer: A
49) It has been observed that organisms on islands are different from, but closely related to, similar forms found on the nearest continent. This is taken as evidence that A) island forms and mainland forms descended from common ancestors. B) common environments are inhabited by the same organisms. C) the islands were originally part of the continent. D) the island forms and mainland forms are converging. E) island forms and mainland forms have identical gene pools.
Answer: A
5) DNA sequences in many human genes are very similar to the sequences of corresponding genes in chimpanzees. The most likely explanation for this result is that A) humans and chimpanzees share a relatively recent common ancestor. B) humans evolved from chimpanzees. C) chimpanzees evolved from humans. D) convergent evolution led to the DNA similarities. E) humans and chimpanzees are not closely related.
Answer: A
5) Expression of a cloned eukaryotic gene in a bacterial cell involves many challenges. The use of mRNA and reverse transcriptase is part of a strategy to solve the problem of A) post- transcriptional processing. B) electroporation. C) post- translational processing. D) nucleic acid hybridization. E) restriction fragment ligation.
Answer: A
5) For this pair of items, choose the option that best describes their relationship. (A) The number of purines in the DNA strand 5ʹ -AAGAGGAGAAA-3ʹ (B) The number of pyrimidines in the DNA strand 5ʹ -AAGAGGAGAAA-3ʹ A) Item (A) is greater than item (B). B) Item (A) is less than item (B). C) Item (A) is exactly or very approximately equal to item (B). D) Item (A) may stand in more than one of the above relations to item (B).
Answer: A
5) The structural level of a protein least affected by a disruption in hydrogen bonding is the A) primary level. B) secondary level. C) tertiary level. D) quaternary level. E) All structural levels are equally affected.
Answer: A
5) Which of the following statements describes the results of this reaction? C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + Energy A) C6H12O6 is oxidized and O 2 is reduced. B) O2 is oxidized and H 2O is reduced. C) CO2 is reduced and O2 is oxidized. D) C6H12O6 is reduced and CO2 is oxidized. E) O2 is reduced and CO2 is oxidized.
Answer: A
5) Which of these variables is likely to undergo the largest change in value as the result of a mutation that introduces a brand -new allele into a populationʹs gene pool at a locus that had formerly been fixed? A) Average heterozygosity B) Nucleotide variability C) Geographic variability D) Average number of loci
Answer: A
5) Why are viruses referred to as obligate parasites? A) They cannot reproduce outside of a host cell. B) Viral DNA always inserts itself into host DNA. C) They invariably kill any cell they infect. D) They can incorporate nucleic acids from other viruses. E) They must use enzymes encoded by the virus itself.
Answer: A
51) Which of the following bests describes the reaction? A) negative △G, spontaneous B) positive △G, nonspontaneous C) positive △G, exergonic D) negative △G, endergonic E) △G of zero, chemical equilibrium
Answer: A
51) Which of these five species (V—Z) in the evolutionary tree would likely have fossil records indicating that punctuated equilibrium was an important part of their evolutionary history? A) V and W B) V and Y C) X and Y D) W, Y, and Z E) X, Y, and Z
Answer: A
52) As a ribosome translocates along an mRNA molecule by one codon, which of the following occurs? A) The tRNA that was in the A site moves into the P site. B) The tRNA that was in the P site moves into the A site. C) The tRNA that was in the A site moves to the E site and is released. D) The tRNA that was in the A site departs from the ribosome via a tunnel. E) The polypeptide enters the E site.
Answer: A
52) Figure 5.7 best illustrates the A) secondary structure of a polypeptide. B) tertiary structure of a polypeptide. C) quaternary structure of a protein. D) double helix structure of DNA. E) primary structure of a polysaccharide.
Answer: A
52) In 1956 Tijo and Levan first successfully counted human chromosomes. The reason it would have taken so many years to have done so would have included all but which of the following? A) Watson and Crickʹs structure of DNA was not done until 1953. B) Chromosomes were piled up on top of one another in the nucleus. C) Chromosomes were not distinguishable during interphase. D) A method had not yet been devised to halt mitosis at metaphase.
Answer: A
52) The ionic bond of sodium chloride is formed when A) chlorine gains an electron from sodium. B) sodium and chlorine share an electron pair. C) sodium and chlorine both lose electrons from their outer valence shells. D) sodium gains an electron from chlorine. E) chlorine gains a proton from sodium.
Answer: A
52) Which of the following sets of materials are required by both eukaryotes and prokaryotes for replication? A) double-stranded DNA, 4 kinds of dNTPs, primers, origins B) topoisomerases, telomerase, polymerases C) G-C rich regions, polymerases, chromosome nicks D) nucleosome loosening, 4 dNTPs, 4 rNTPs E) ligase, primers, nucleases
Answer: A
53) Carbon dioxide (CO2 ) is readily soluble in water, according to the equation CO 2 + H2O → H2CO3 . Carbonic acid (H2CO3 ) is a weak acid. Respiring cells release CO 2 . What prediction can we make about the pH of blood as that blood first comes in contact with respiring cells? A) Blood pH will decrease slightly. B) Blood pH will increase slightly. C) Blood pH will remain unchanged. D) Blood pH will first increase, then decrease as CO 2 combines with hemoglobin. E) Blood pH will first decrease, then increase sharply as CO 2 combines with hemoglobin.
Answer: A
53) Human caspases can be activated by A) irreparable DNA damage or protein misfolding. B) infrequency of cell division. C) high concentrations of vitamin C. D) a death-signaling ligand being removed from its receptor. E) electron transport.
Answer: A
53) Hydrangea plants of the same genotype are planted in a large flower garden. Some of the plants produce blue flowers and others pink flowers. This can be best explained by which of the following? A) Environmental factors such as soil pH B) The allele for blue hydrangea being completely dominant C) The alleles being codominant D) The fact that a mutation has occurred E) Acknowledging that multiple alleles are involved
Answer: A
53) What are polyribosomes? A) groups of ribosomes reading a single mRNA simultaneously B) ribosomes containing more than two subunits C) multiple copies of ribosomes associated with giant chromosomes D) aggregations of vesicles containing ribosomal RNA E) ribosomes associated with more than one tRNA
Answer: A
39) According to the induced fit hypothesis of enzyme catalysis, which of the following is correct? A) The binding of the substrate depends on the shape of the active site. B) Some enzymes change their structure when activators bind to the enzyme. C) A competitive inhibitor can outcompete the substrate for the active site. D) The binding of the substrate changes the shape of the enzymeʹs active site. E) The active site creates a microenvironment ideal for the reaction.
Answer: D
54) How does the sexual life cycle increase the genetic variation in a species? A) By allowing independent assortment of chromosomes B) By allowing fertilization C) By increasing gene stability D) By conserving chromosomal gene order E) By decreasing mutation frequency
Answer: A
54) The situation as described in the paragraph above should select most directly against males that A) are unable to distinguish food items that are red from those of other colors. B) are older, but still healthy. C) are capable of defending only moderately sized territories. D) have slightly lower levels of testosterone during breeding season than have other males. E) have no prior experience courting female house finches.
Answer: A
39) An inhibitor of which of the following could be used to block the release of calcium from the endoplasmic reticulum? A) tyrosine kinases B) serine/threonine kinases C) phosphodiesterase D) phospholipase C E) adenylyl cyclase
Answer: D
54) Which of these five species is the extant (i.e., not extinct) species that is most closely related to species X, and why is this so? A) V; shared a common ancestor with X most recently B) W; shared a common ancestor with X most recently C) Y; arose in the same fashion (i.e., at the same tempo) as X D) Z; shared a common ancestor with X most recently, and arose in the same fashion as X E) This tree does not provide enough information to answer this question.
Answer: A
55) If the fossil records of apes and humans alike show a trend toward decreasing larynx size in adult females, and increasing larynx size in adult males, then A) sexual dimorphism was developing over time in these species. B) intrasexual selection seems to have occurred. C) the ʺgood genesʺ hypothesis was refuted by these data. D) stabilizing selection was occurring in these species concerning larynx size. E) selection was acting more directly upon genotype than upon phenotype.
Answer: A
55) Scientists developed a set of guidelines to address the safety of DNA technology. Which of the following is one of the adopted safety measures? A) Microorganisms used in recombinant DNA experiments are genetically crippled to ensure that they cannot survive outside of the laboratory. B) Genetically modified organisms are not allowed to be part of our food supply. C) Transgenic plants are engineered so that the plant genes cannot hybridize. D) Experiments involving HIV or other potentially dangerous viruses have been banned. E) Recombinant plasmids cannot be replicated.
Answer: A
55) Which of the following statements describes genomic imprinting ? A) It explains cases in which the gender of the parent from whom an allele is inherited affects the expression of that allele. B) It is greatest in females because of the larger maternal contribution of cytoplasm. C) It may explain the transmission of Duchenne muscular dystrophy. D) It involves an irreversible alteration in the DNA sequence of imprinted genes.
Answer: A
56) In most cells, there are electrochemical gradients of many ions across the plasma membrane even though there are usually only one or two electrogenic pumps present in the membrane. The gradients of the other ions are most likely accounted for by A) cotransport proteins. B) ion channels. C) carrier proteins. D) B and C only E) A, B, and C
Answer: A
56) Independent assortment of chromosomes is a result of A) the random and independent way in which each pair of homologous chromosomes lines up at the metaphase plate during meiosis I. B) the random nature of the fertilization of ova by sperm. C) the random distribution of the sister chromatids to the two daughter cells during anaphase II. D) the relatively small degree of homology shared by the X and Y chromosomes. E) All of the above
Answer: A
57) The fact that plants can be cloned from somatic cells demonstrates that A) differentiated cells retain all the genes of the zygote. B) genes are lost during differentiation. C) the differentiated state is normally very unstable. D) differentiated cells contain masked mRNA. E) differentiation does not occur in plants.
Answer: A
57) Which molecule contains an amino functional group, but is not an amino acid?
Answer: A
58) Competitive inhibitors block the entry of substrate into the active site of an enzyme. On which of the following properties of an active site does this primarily depend? A) the ability of an enzyme to form a template for holding and joining molecules B) the enzymeʹs ability to stretch reactants and move them toward a transition state C) the enzyme providing an appropriate microenvironment conducive to a reactionʹs occurrence D) the enzyme forming covalent bonds with the reactants E) the enzyme becoming too saturated because of the concentration of substrate
Answer: A
58) The Darwinian fitness of an individual is measured most directly by A) the number of its offspring that survive to reproduce. B) the number of ʺgood genesʺ it possesses. C) the number of mates it attracts. D) its physical strength. E) how long it lives.
Answer: A
58) The pH of the inner thylakoid space has been measured, as have the pH of the stroma and of the cytosol of a particular plant cell. Which, if any, relationship would you expect to find? A) The pH within the thylakoid is less than that of the stroma. B) The pH of the stroma is higher than that of the other two measurements. C) The pH of the stroma is higher than that of the thylakoid space but lower than that of the cytosol. D) The pH of the thylakoid space is higher than that anywhere else in the cell. E) There is no consistent relationship.
Answer: A
59) Which of the following statements is true concerning Figure 10.3? A) It represents cell processes involved in C4 photosynthesis. B) It represents the type of cell structures found in CAM plants. C) It represents an adaptation that maximizes photorespiration. D) It represents a C3 photosynthetic system. E) It represents a relationship between plant cells that photosynthesize and those that cannot.
Answer: A
39) In which population is the frequency of the allele for brown feathers highest? A) Population A. B) Population B. C) Population C. D) They are all the same. E) It is impossible to tell from the information given.
Answer: D
39) Starting with citrate, which of the following combinations of products would result from three turns of the citric acid cycle? A) 1 ATP, 2 CO2 , 3 NADH, and 1 FADH 2 B) 2 ATP, 2 CO2 , 1 NADH, and 3 FADH 2 C) 3 ATP, 3 CO2 , 3 NADH, and 3 FADH 2 D) 3 ATP, 6 CO2 , 9 NADH, and 3 FADH 2 E) 38 ATP, 6 CO2 , 3 NADH, and 12 FADH 2
Answer: D
6) A biologist discovers two populations of wolf spiders whose members appear identical. Members of one population are found in the leaf litter deep within the woods. Members of the other population are found in the grass at the edge of the woods. The biologist decides to designate the members of the two populations as two separate species. Which species concept is this biologist most closely utilizing? A) ecological B) biological C) morphological D) phylogenetic
Answer: A
6) Homeotic genes A) encode transcription factors that control the expression of genes responsible for specific anatomical structures. B) are found only in Drosophila and other arthropods. C) are the only genes that contain the homeobox domain. D) encode proteins that form anatomical structures in the fly. E) are responsible for patterning during plant development.
Answer: A
6) In terms of the hierarchical organization of life, a bacterium is at the __________ level of organization, whereas a human is at the __________ level of organization. A) single-celled organism; multicellular organism B) single organelle; organism C) organelle; organ system D) single tissue; multicellular organism E) tissue; organism
Answer: A
6) The human genome is minimally contained in which of the following? A) Every human cell B) Each human chromosome C) The entire DNA of a single human D) The entire human population E) Each human gene
Answer: A
39) Which of the following removes the RNA nucleotides from the primer and adds equivalent DNA nucleotides to the 3ʹ end of Okazaki fragments? A) helicase B) DNA polymerase III C) ligase D) DNA polymerase I E) primase
Answer: D
6) The mass number of an element can be easily approximated by adding together the number of __________ in an atom of that element. A) protons and neutrons B) energy levels C) protons and electrons D) neutrons and electrons E) isotopes
Answer: A
6) When electrons flow along the electron transport chains of mitochondria, which of the following changes occurs? A) The pH of the matrix increases. B) ATP synthase pumps protons by active transport. C) The electrons gain free energy. D) The cytochromes phosphorylate ADP to form ATP. E) NAD+ is oxidized.
Answer: A
6) Which statement is true of all atoms that are anions? A) The atom has more electrons than protons. B) The atom has more protons than electrons. C) The atom has fewer protons than does a neutral atom of the same element. D) The atom has more neutrons than protons. E) The net charge is 12.
Answer: A
60) In animals, embryonic stem cells differ from adult stem cells in that A) embryonic stem cells are totipotent, and adult stem cells are pluripotent. B) embryonic stem cells are pluripotent, and adult stem cells are totipotent. C) embryonic stem cells have more genes than adult stem cells. D) embryonic stem cells have fewer genes than adult stem cells. E) embryonic stem cells are localized to specific sites within the embryo, whereas adult stem cells are spread throughout the body.
Answer: A
60) Which of the following is not considered to be a weak molecular interaction? A) a covalent bond B) a van der Waals interaction C) an ionic bond in the presence of water D) a hydrogen bond E) A and B only
Answer: A
61) A certain kind of snail can have a right-handed direction of shell coiling (D) or left handed coiling (d ). If direction of coiling is due to a protein deposited by the mother in the egg cytoplasm, then a Dd egg-producing snail and a dd sperm-producing snail will have offspring of which genotype(s) and phenotype(s)? A) 1/2 Dd : 1/2 dd; all right coiling B) All Dd ; all right coiling C) 1/2 Dd : 1/2 dd; half right and half left coiling D) All Dd ; all left coiling E) All Dd ; half right and half left coiling
Answer: A
62) Sometimes atoms form molecules by sharing two pairs of valence electrons. When this occurs, the atoms are said to be joined by A) a double covalent bond. B) an electronegative bond. C) a hydrogen bond. D) a protonic bond. E) a complex bond.
Answer: A
62) The sodium-potassium pump in animal cells requires cytoplasmic ATP to pump ions across the plasma membrane. When the proteins of the pump are first synthesized in the rough ER, what side of the ER membrane will the ATP binding site be on? A) It will be on the cytoplasmic side of the ER. B) It will be on the side facing the interior of the ER. C) It could be facing in either direction because the orientation of proteins is scrambled in the Golgi apparatus. D) It doesnʹt matter, because the pump is not active in the ER.
Answer: A
62) Why do histones bind tightly to DNA? A) Histones are positively charged, and DNA is negatively charged. B) Histones are negatively charged, and DNA is positively charged. C) Both histones and DNA are strongly hydrophobic. D) Histones are covalently linked to the DNA. E) Histones are highly hydrophobic, and DNA is hydrophilic.
Answer: A
63) An ideal procedure for fetal testing in humans would have which of the following features? A) Lowest risk procedure that would provide the most reliable information B) The procedure that can test for the greatest number of traits at once C) A procedure that provides a 3D image of the fetus D) The procedure that can be performed at the earliest time in the pregnancy E) A procedure that could test for the carrier status of the fetus
Answer: A
63) When the ribosome reaches a stop codon on the mRNA, no corresponding tRNA enters the A site. If the translation reaction were to be experimentally stopped at this point, which of the following would you be able to isolate? A) an assembled ribosome with a polypeptide attached to the tRNA in the P site B) separated ribosomal subunits, a polypeptide, and free tRNA C) an assembled ribosome with a separated polypeptide D) separated ribosomal subunits with a polypeptide attached to the tRNA E) a cell with fewer ribosomes
Answer: A
63) Which of the following represents the order of increasingly higher levels of organization of chromatin? A) nucleosome, 30-nm chromatin fiber, looped domain B) looped domain, 30 -nm chromatin fiber, nucleosome C) looped domain, nucleosome, 30 -nm chromatin fiber D) nucleosome, looped domain, 30 -nm chromatin fiber E) 30-nm chromatin fiber, nucleosome, looped domain
Answer: A
64) CAM plants keep stomata closed in daytime, thus reducing loss of water. They can do this because they A) fix CO2 into organic acids during the night. B) fix CO2 into sugars in the bundle-sheath cells. C) fix CO2 into pyruvate in the mesophyll cells. D) use the enzyme phosphofructokinase, which outcompetes rubisco for CO 2 . E) use photosystems I and II at night.
Answer: A
64) Which of the following serve as sources of developmental information? A) cytoplasmic determinants such as mRNAs and proteins produced before fertilization B) signal molecules produced by the maturing zygote C) ubiquitous enzymes such as DNA polymerase and DNA ligase D) paternally deposited proteins E) specific operons within the zygote genome
Answer: A
65) After the first disruption, when electron transfer and ATP synthesize still occur, what must be present? A) all of the electron transport proteins as well as ATP synthase B) all of the electron transport system and the ability to add CoA to acetyl groups C) the ATP synthase system is sufficient D) the electron transport system is sufficient E) plasma membranes like those bacteria use for respiration
Answer: A
65) Recent evidence shows that the extracellular matrix can take part in regulating the expression of genes. A likely possibility for this might be which of the following? A) Mechanical signals of the ECM can alter the cytoskeleton, which can alter intracellular signaling. B) Intracellular signals might cause changes in the fibronectin binding to the cell surface. C) Orientation of microfilaments to the ECM can change the gene activity. D) Fibronectin binds to integrins built into the plasma membrane. E) Proteoglycans in the ECM become large enough in aggregate to force genetic alteration.
Answer: A
67) Familial hypercholesterolemia is characterized by which of the following? A) defective LDL receptors on the cell membranes B) poor attachment of the cholesterol to the extracellular matrix of cells C) a poorly formed lipid bilayer that cannot incorporate cholesterol into cell membranes D) inhibition of the cholesterol active transport system in red blood cells E) a general lack of glycolipids in the blood cell membranes
Answer: A
68) The difference between pinocytosis and receptor -mediated endocytosis is that A) pinocytosis brings only water into the cell, but receptor -mediated endocytosis brings in other molecules as well. B) pinocytosis increases the surface area of the plasma membrane whereas receptor-mediated endocytosis decreases the plasma membrane surface area. C) pinocytosis is nonselective in the molecules it brings into the cell, whereas receptor-mediated endocytosis offers more selectivity. D) pinocytosis requires cellular energy, but receptor-mediated endocytosis does not. E) pinocytosis can concentrate substances from the extracellular fluid, but receptor-mediated endocytosis cannot.
Answer: A
68) Which of the following best describes the flow of information in eukaryotic cells? A) DNA → RNA → proteins B) RNA → proteins → DNA C) proteins → DNA → RNA D) RNA → DNA → proteins E) DNA → proteins → RNA
Answer: A
7) Cell differentiation always involves the A) production of tissue -specific proteins, such as muscle actin. B) movement of cells. C) transcription of the myoD gene. D) selective loss of certain genes from the genome. E) cellʹs sensitivity to environmental cues such as light or heat.
Answer: A
7) Consider this pathway: epinephrine → G protein-coupled receptor → G protein → adenylyl cyclase → cAMP. Identify the second messenger. A) cAMP B) G protein C) GTP D) adenylyl cyclase E) G protein-coupled receptor
Answer: A
7) In the cells of some organisms, mitosis occurs without cytokinesis. This will result in A) cells with more than one nucleus. B) cells that are unusually small. C) cells lacking nuclei. D) destruction of chromosomes. E) cell cycles lacking an S phase.
Answer: A
7) Males are more often affected by sex- linked traits than females because A) males are hemizygous for the X chromosome. B) male hormones such as testosterone often alter the effects of mutations on the X chromosome. C) female hormones such as estrogen often compensate for the effects of mutations on the X. D) X chromosomes in males generally have more mutations than X chromosomes in females. E) mutations on the Y chromosome often worsen the effects of X - linked mutations.
Answer: A
70) A pedigree analysis for a given disorderʹs occurrence in a family shows that, although both parents of an affected child are normal, each of the parents has had affected relatives with the same condition. The disorder is then which of the following? A) Recessive B) Dominant C) Incompletely dominant D) Maternally inherited E) A new mutation
Answer: A
70) Among enzymes, kinases catalyze phosphorylation, while phosphatases catalyze removal of phosphate(s). A cellʹs use of these enzymes can therefore function as an on -off switch for various processes. Which of the following is probably involved? A) the change in a proteinʹs charge leading to a conformational change B) the change in a proteinʹs charge leading to cleavage C) a change in the optimal pH at which a reaction will occur D) a change in the optimal temperature at which a reaction will occur E) the excision of one or more peptides
Answer: A
70) Mules are relatively long - lived and hardy organisms that cannot, generally speaking, perform successful meiosis. Consequently, which statement about mules is true? A) They have a relative evolutionary fitness of zero. B) Their offspring have less genetic variation than the parents. C) Mutations cannot occur in their genomes. D) If crossing-over happens in mules, then it must be limited to prophase of mitosis. E) When two mules interbreed, genetic recombination cannot occur by meiotic crossing over, but only by the act of fertilization.
Answer: A
70) Sickle-cell disease is probably the result of which kind of mutation? A) point B) frameshift C) nonsense D) nondisjunction E) both B and D
Answer: A
70) The hybrid orbitals in a molecule of methane are oriented A) toward the corners of a tetrahedron centered on the carbon atom. B) toward the corners of a cube centered on the carbon atom. C) toward the corners of a triangle centered on the carbon atom. D) toward the corners of a rectangle centered on the carbon atom. E) toward the edges of an oval centered on the carbon atom.
Answer: A
70) The product of the bicoid gene in Drosophila provides essential information about A) the anterior-posterior axis. B) the dorsal-ventral axis. C) the left-right axis. D) segmentation. E) lethal genes.
Answer: A
72) In the 5—7 million years that the hominid lineage has been diverging from its common ancestor with the great apes, dozens of hominid species have arisen, often with several species coexisting in time and space. As recently as 30,000 years ago, Homo sapiens coexisted with Homo neanderthalensis. Both species had large brains and advanced intellects. The fact that these traits were common to both species is most easily explained by which of the following? A) species selection B) uniformitarianism C) sexual selection D) A and B only E) A, B, and C
Answer: A
72) Mutations in these genes lead to transformations in the identity of entire body parts: A) homeotic genes B) segmentation genes C) egg-polarity genes D) morphogens E) inducers
Answer: A
72) Which of the following DNA mutations is the most likely to be damaging to the protein it specifies? A) a base-pair deletion B) a codon substitution C) a substitution in the last base of a codon D) a codon deletion E) a point mutation
Answer: A
72) Which of the following best describes chemical equilibrium? A) Forward and reverse reactions continue with no effect on the concentrations of the reactants and products. B) Concentrations of products are higher than the concentrations of the reactants. C) Forward and reverse reactions have stopped so that the concentration of the reactants equals the concentration of the products. D) Reactions stop only when all reactants have been converted to products. E) There are equal concentrations of reactants and products, and the reactions have stopped.
Answer: A
75) Which of the following occurs in the cytosol of a eukaryotic cell? A) glycolysis and fermentation B) fermentation and chemiosmosis C) oxidation of pyruvate to acetyl CoA D) citric acid cycle E) oxidative phosphorylation
Answer: A
78) In the absence of oxygen, yeast cells can obtain energy by fermentation, resulting in the production of A) ATP, CO2 , and ethanol (ethyl alcohol). B) ATP, CO2 , and lactate. C) ATP, NADH, and pyruvate. D) ATP, pyruvate, and oxygen. E) ATP, pyruvate, and acetyl CoA.
Answer: A
79) In alcohol fermentation, NAD+ is regenerated from NADH during which of the following? A) reduction of acetaldehyde to ethanol (ethyl alcohol) B) oxidation of pyruvate to acetyl CoA C) reduction of pyruvate to form lactate D) oxidation of NAD+ in the citric acid cycle E) phosphorylation of ADP to form ATP
Answer: A
79) There are those who claim that the theory of evolution cannot be true because the apes, which are supposed to be closely related to humans, do not likewise share the same large brains, capacity for complicated speech, and tool-making capability. They reason that if these features are generally beneficial, then the apes should have evolved them as well. Which of these provides the best argument against this misconception? A) Advantageous alleles do not arise on demand. B) A populationʹs evolution is limited by historical constraints. C) Adaptations are often compromises. D) Evolution can be influenced by environmental change.
Answer: A
79) What do gap genes, pair - rule genes, segment polarity genes, and homeotic genes all have in common? A) Their products act as transcription factors. B) They have no counterparts in animals other than Drosophila. C) Their products are all synthesized prior to fertilization. D) They act independently of other positional information. E) They apparently can be activated and inactivated at any time of the flyʹs life.
Answer: A
8) A mutation that inactivates the regulatory gene of a repressible operon in an E. coli cell would result in A) continuous transcription of the structural gene controlled by that regulator. B) complete inhibition of transcription of the structural gene controlled by that regulator. C) irreversible binding of the repressor to the operator. D) inactivation of RNA polymerase by alteration of its active site. E) continuous translation of the mRNA because of alteration of its structure.
Answer: A
8) Bioinformatics can be used to scan sequences for probable genes looking for start and stop sites for transcription and for translation, for probable splice sites, and for sequences known to be found in other known genes. Such sequences containing these elements are called A) expressed sequence tags. B) cDNA. C) multigene families. D) proteomes. E) short tandem repeats.
Answer: A
8) Cyanide binds with at least one molecule involved in producing ATP. If a cell is exposed to cyanide, most of the cyanide would be found within the A) mitochondria. B) ribosomes. C) peroxisomes. D) lysosomes. E) endoplasmic reticulum.
Answer: A
8) Which of the following statements describes NAD +? A) NAD+ is reduced to NADH during both glycolysis and the citric acid cycle. B) NAD+ has more chemical energy than NADH. C) NAD+ is reduced by the action of hydrogenases. D) NAD+ can donate electrons for use in oxidative phosphorylation. E) In the absence of NAD+ , glycolysis can still function.
Answer: A
80) Which of the following statements describes proto-oncogenes? A) They can code for proteins associated with cell growth. B) They are introduced to a cell initially by retroviruses. C) They are produced by somatic mutations induced by carcinogenic substances. D) Their normal function is to suppress tumor growth E) They are underexpressed in cancer cells
Answer: A
81) Which of the following is characteristic of the product of the p53 gene? A) It is an activator for other genes. B) It speeds up the cell cycle. C) It causes cell death via apoptosis. D) It allows cells to pass on mutations due to DNA damage. E) It slows down the rate of DNA replication by interfering with the binding of DNA polymerase.
Answer: A
82) Glycolysis is thought to be one of the most ancient of metabolic processes. Which statement supports this idea? A) Glycolysis is the most widespread metabolic pathway. B) Glycolysis neither uses nor needs O 2 . C) Glycolysis is found in all eukaryotic cells. D) The enzymes of glycolysis are found in the cytosol rather than in a membrane-enclosed organelle. E) Ancient prokaryotic cells, the most primitive of cells, made extensive use of glycolysis long before oxygen was present in Earthʹs atmosphere.
Answer: A
84) The cancer-causing forms of the Ras protein are involved in which of the following processes? A) relaying a signal from a growth factor receptor B) DNA replication C) DNA repair D) cell-cell adhesion E) cell division
Answer: A
86) A genetic test to detect predisposition to cancer would likely examine the APC gene for involvement in which type(s) of cancer? A) colorectal only B) lung and breast C) small intestinal and esophageal D) lung only E) lung and prostate
Answer: A
87) You have a friend who lost 7 kg (about 15 pounds) of fat on a ʺlow carbʺ diet. How did the fat leave her body? A) It was released as CO2 and H 2O. B) Chemical energy was converted to heat and then released. C) It was converted to ATP, which weighs much less than fat. D) It was broken down to amino acids and eliminated from the body. E) It was converted to urine and eliminated from the body.
Answer: A
89) If there are two children born from the same parents, and child one inherits a predisposition to retinoblastoma (one of the mutations) and child two does not, but both children develop the retinoblastoma, which of the following would you expect? A) an earlier age of onset in child one B) a history of exposure to mutagens in child one but not in child two C) a more severe cancer in child one D) increased levels of apoptosis in both children E) decreased levels of DNA repair in child one
Answer: A
89) Phosphofructokinase is an allosteric enzyme that catalyzes the conversion of fructose-6-phosphate to fructose -1,6-bisphosphate, an early step of glycolysis. In the presence of oxygen, an increase in the amount ATP in a cell would be expected to A) inhibit the enzyme and thus slow the rates of glycolysis and the citric acid cycle. B) activate the enzyme and thus slow the rates of glycolysis and the citric acid cycle. C) inhibit the enzyme and thus increase the rates of glycolysis and the citric acid cycle. D) activate the enzyme and increase the rates of glycolysis and the citric acid cycle. E) inhibit the enzyme and thus increase the rate of glycolysis and the concentration of citrate.
Answer: A
9) A sexually reproducing animal has two unlinked genes, one for head shape ( H) and one for tail length (T). Its genotype is HhTt. Which of the following genotypes is possible in a gamete from this organism? A) HT B) Hh C) HhTt D) T E) tt
Answer: A
9) Males of one species sing only when its predators are absent; males of another species sing only when its predators are present. A) behavioral B) gametic C) habitat D) temporal E) mechanical
Answer: A
9) Which of the following types of reactions would decrease the entropy within a cell? A) dehydration reactions B) hydrolysis C) respiration D) digestion E) catabolism
Answer: A
98) Which of the following molecules has (have) a functional group that frequently is involved in maintaining the tertiary structure of a protein? A) 2 B) 3 C) 9 D) 11 E) 9 and 11
Answer: A
A) structural isomers B) geometric isomers C) enantiomers D) isotopes
Answer: A
6) A fruit fly that is true-breeding for gray body, vestigial wings ( b+ b+ vg vg) is mated with one that is true-breeding for black body, normal wings ( b b vg+ vg+ ). A) Draw the chromosomes for each P generation fly, showing the position of each allele. B) Draw the chromosomes and label the alleles for an F 1 fly. C) Suppose an F1 female is testcrossed. Draw the chromosomes of the resulting offspring in a Punnett square like the one at the bottom of Fig. 15.10 in your textbook. D) Knowing that the distance between these two genes is 17 map units, predict the phenotypic ratios of these offspring.
Answer: A)
21) What is the probability that each of the following pairs of parents will produce the indicated offspring? (Assume independent assortment of all gene pairs.) A) AABBCC × aabbcc AaBbCc B) AABbCc × AaBbCc AAbbCC C) AaBbCc × AaBbCc AaBbCc D) aaBbCC × AABbcc AaBbCc
Answer: A) 1, B) 1⁄32, C) 1⁄8, D) 1⁄2
20) The genotype of F1 individuals in a tetrahybrid cross is AaBbCcDd. Assuming independent assortment of these four genes, what are the probabilities that F 2 offspring will have the following genotypes? A) aabbccdd B) AaBbCcDd C) AABBCCDD D) AaBBccDd E) AaBBCCdd
Answer: A) 1⁄256, B) 1⁄16, C) 1⁄256, D) 1⁄64, E) 1/128
1) All the organisms on your campus make up A) an ecosystem. B) a community. C) a population. D) an experimental group. E) a taxonomic domain.
Answer: B
1) Catastrophism, meaning the regular occurrence of geological or meteorological disturbances (catastrophes), was Cuvierʹs attempt to explain the existence of A) evolution. B) the fossil record. C) uniformitarianism. D) the origin of new species. E) natural selection.
Answer: B
1) Choose the pair of terms that correctly completes this sentence: Catabolism is to anabolism as __________ is to __________. A) exergonic; spontaneous B) exergonic; endergonic C) free energy; entropy D) work; energy E) entropy; enthalpy
Answer: B
1) For mapping studies of genomes, most of which were far along before 2000, the 3 -stage method was often used. Which is the usual order in which the stages were performed, assuming some overlap of the three? A) genetic map, sequencing of fragments, physical map B) linkage map, physical map, sequencing of fragments C) sequencing of entire genome, physical map, genetic map D) cytogenetic linkage, sequencing, physical map E) physical map, linkage map, sequencing
Answer: B
1) For this pair of items, choose the option that best describes their relationship. (A) The number of alpha glucose 1 -4 linkages in cellulose (B) The number of alpha glucose 1 -4 linkages in starch A) Item (A) is greater than item (B). B) Item (A) is less than item (B). C) Item (A) is exactly or very approximately equal to item (B). D) Item (A) may stand in more than one of the above relations to item (B).
Answer: B
1) In eukaryotic cells, transcription cannot begin until A) the two DNA strands have completely separated and exposed the promoter. B) several transcription factors have bound to the promoter. C) the 5ʹ caps are removed from the mRNA. D) the DNA introns are removed from the template. E) DNA nucleases have isolated the transcription unit.
Answer: B
1) In what way do the membranes of a eukaryotic cell vary? A) Phospholipids are found only in certain membranes. B) Certain proteins are unique to each membrane. C) Only certain membranes of the cell are selectively permeable. D) Only certain membranes are constructed from amphipathic molecules. E) Some membranes have hydrophobic surfaces exposed to the cytoplasm, while others have hydrophilic surfaces facing the cytoplasm.
Answer: B
1) Organic chemistry is currently defined as A) the study of compounds made only by living cells. B) the study of carbon compounds. C) the study of vital forces. D) the study of natural (as opposed to synthetic) compounds. E) the study of hydrocarbons.
Answer: B
1) The largest unit within which gene flow can readily occur is a A) population. B) species. C) genus. D) hybrid. E) phylum.
Answer: B
1) Through a microscope, you can see a cell plate beginning to develop across the middle of a cell and nuclei re- forming on either side of the cell plate. This cell is most likely A) an animal cell in the process of cytokinesis. B) a plant cell in the process of cytokinesis. C) an animal cell in the S phase of the cell cycle. D) a bacterial cell dividing. E) a plant cell in metaphase.
Answer: B
1) What is the reducing agent in the following reaction? Pyruvate + NADH + H+ → Lactate + NAD+ A) oxygen B) NADH C) NAD+ D) lactate E) pyruvate
Answer: B
1) What is the term for metabolic pathways that release stored energy by breaking down complex molecules? A) anabolic pathways B) catabolic pathways C) fermentation pathways D) thermodynamic pathways E) bioenergetic pathways
Answer: B
1) Which of the following is not an observation or inference on which natural selection is based? A) There is heritable variation among individuals. B) Poorly adapted individuals never produce offspring. C) Species produce more offspring than the environment can support. D) Individuals whose characteristics are best suited to the environment generally leave more offspring than those whose characteristics are less suited. E) Only a fraction of the offspring produced by an individual may survive.
Answer: B
1) Which of the following tools of recombinant DNA technology is incorrectly paired with its use? A) restriction enzyme-production of RFLPs B) DNA ligase-enzyme that cuts DNA, creating the sticky ends of restriction fragments C) DNA polymerase-used in a polymerase chain reaction to amplify sections of DNA D) reverse transcriptase-production of cDNA from mRNA E) electrophoresis-separation of DNA fragments
Answer: B
1) Which of these is a statement that Darwin would have rejected? A) Environmental change plays a role in evolution. B) The smallest entity that can evolve is an individual organism. C) Individuals can acquire new characteristics as they respond to new environments or situations. D) Inherited variation in a population is a necessary precondition for natural selection to operate. E) Natural populations tend to produce more offspring than the environment can support.
Answer: B
1) Why did the improvement of microscopy techniques in the late 1800s set the stage for the emergence of modern genetics? A) It revealed new and unanticipated features of Mendelʹs pea plant varieties. B) It allowed the study of meiosis and mitosis, revealing parallels between behaviors of genes and chromosomes. C) It allowed scientists to see the DNA present within chromosomes. D) It led to the discovery of mitochondria. E) It showed genes functioning to direct the formation of enzymes.
Answer: B
10) It was important that Mendel examined not just the F 1 generation in his breeding experiments, but the F2 generation as well, because A) he obtained very few F1 progeny, making statistical analysis difficult. B) parental traits that were not observed in the F1 reappeared in the F 2 . C) analysis of the F1 progeny would have allowed him to discover the law of segregation, but not the law of independent assortment. D) the dominant phenotypes were visible in the F 2 generation, but not in the F 1 . E) many of the F 1 progeny died.
Answer: B
10) One of the following people was the first to suggest that organic compounds, those found in living organisms, were distinctly different from inorganic compounds found in the nonliving world. Though this suggestion is now known to be incorrect, it stimulated important research into organic compounds. Who suggested this? A) Stanley Miller B) Jakob Berzelius C) Friedrich Wohler D) Hermann Kolbe E) August Kekulé
Answer: B
10) Proto-oncogenes can change into oncogenes that cause cancer. Which of the following best explains the presence of these potential time bombs in eukaryotic cells? A) Proto-oncogenes first arose from viral infections. B) Proto-oncogenes normally help regulate cell division. C) Proto-oncogenes are genetic ʺjunk.ʺ D) Proto-oncogenes are mutant versions of normal genes. E) Cells produce proto-oncogenes as they age.
Answer: B
10) Transcription of the structural genes in an inducible operon A) occurs continuously in the cell. B) starts when the pathwayʹs substrate is present. C) starts when the pathwayʹs product is present. D) stops when the pathwayʹs product is present. E) does not result in the production of enzymes.
Answer: B
10) Why is it important to know what microscopy method was used to prepare the images you wish to study? A) so that you can judge whether the images you are seeing are of cells or of organelles B) so that you can make a judgment about the likelihood of artifacts having been introduced in the preparation C) so that you can decide whether the image is actually of the size described D) so that you can know whether to view the image in color or not E) so that you can interpret the correct biochemical process that is occurring
Answer: B
11) Darwinʹs mechanism of natural selection required long time spans in order to modify species. From whom did Darwin get the concept of Earthʹs ancient age? A) Georges Cuvier B) Charles Lyell C) Alfred Wallace D) Thomas Malthus E) John Henslow
Answer: B
11) If you ran the same experiment without passing light through a prism, what would you predict? A) There would be no difference in results. B) The bacteria would be relatively evenly distributed along the algal filaments. C) The number of bacteria present would decrease due to an increase in the carbon dioxide concentration. D) The number of bacteria present would increase due to an increase in the carbon dioxide concentration. E) The number of bacteria would decrease due to a decrease in the temperature of the water.
Answer: B
11) The molecular formula for glucose is C6H12O6 . What would be the molecular formula for a molecule made by linking three glucose molecules together by dehydration reactions? A) C18H36O18 B) C18H30O15 C) C6H10O5 D) C18H10O15 E) C3H6O3
Answer: B
11) The oxygen consumed during cellular respiration is involved directly in which process or event? A) glycolysis B) accepting electrons at the end of the electron transport chain C) the citric acid cycle D) the oxidation of pyruvate to acetyl CoA E) the phosphorylation of ADP to form ATP
Answer: B
11) Why is it unwise to try to relate an organismʹs complexity with its size or number of cells? A) A very large organism may be composed of very few cells or very few cell types. B) A single-celled organism, such as a bacterium or a protist, still has to conduct all the complex life functions of a large multicellular organism. C) A single-celled organism that is also eukaryotic, such as a yeast, still reproduces mitotically. D) A simple organism can have a much larger genome. E) A complex organism can have a very small and simple genome.
Answer: B
12) Different atomic forms of an element contain the same number of protons but a different number of neutrons. What are these different atomic forms called? A) ions B) isotopes C) neutronic atoms D) isomers E) radioactive atoms
Answer: B
12) Which term describes centromeres uncoupling, sister chromatids separating, and the two new chromosomes moving to opposite poles of the cell? A) telophase B) anaphase C) prometaphase D) metaphase E) prophase
Answer: B
13) Allolactose induces the synthesis of the enzyme lactase. An E. coli cell is presented for the first time with the sugar lactose (containing allolactose) as a potential food source. Which of the following occurs when the lactose enters the cell? A) The repressor protein attaches to the regulator. B) Allolactose binds to the repressor protein. C) Allolactose binds to the regulator gene. D) The repressor protein and allolactose bind to RNA polymerase. E) RNA polymerase attaches to the regulator.
Answer: B
13) An electron loses potential energy when it A) shifts to a less electronegative atom. B) shifts to a more electronegative atom. C) increases its kinetic energy. D) increases its activity as an oxidizing agent. E) attaches itself to NAD+ .
Answer: B
13) At what temperature is water at its densest? A) 0°C B) 4°C C) 32°C D) 100°C E) 212°C
Answer: B
13) The lowest level of biological organization that can perform all the activities required for life is the A) organelle-for example, a chloroplast. B) cell-for example, a skin cell. C) tissue-for example, nervous tissue. D) organ system-for example, the reproductive system. E) organism-for example, an amoeba, dog, human, or maple tree.
Answer: B
13) The synthesis of new DNA requires the prior existence of oligonucleotides to serve as primers. On Earth, these primers are small RNA molecules. This latter observation is evidence in support of the hypothesized existence of A) a snowball Earth. B) earlier genetic systems than those based on DNA. C) the abiotic synthesis of organic monomers. D) the delivery of organic matter to Earth by meteors and comets. E) the endosymbiotic origin of mitochondria and chloroplasts.
Answer: B
14) Why are hydrocarbons insoluble in water? A) The majority of their bonds are polar covalent carbon - to-hydrogen linkages. B) The majority of their bonds are nonpolar covalent carbon - to-hydrogen linkages. C) They are hydrophilic. D) They exhibit considerable molecular complexity and diversity. E) They are lighter than water.
Answer: B
15) How many structural isomers are possible for a substance having the molecular formula C4H10? A) 1 B) 2 C) 4 D) 3 E) 11
Answer: B
15) In response to chemical signals, prokaryotes can do which of the following? A) turn off translation of their mRNA B) alter the level of production of various enzymes C) increase the number and responsiveness of their ribosomes D) inactivate their mRNA molecules E) alter the sequence of amino acids in certain proteins
Answer: B
15) In the thylakoid membranes, what is the main role of the antenna pigment molecules? A) split water and release oxygen to the reaction -center chlorophyll B) harvest photons and transfer light energy to the reaction -center chlorophyll C) synthesize ATP from ADP and P i D) transfer electrons to ferredoxin and then NADPH E) concentrate photons within the stroma
Answer: B
15) Rank the following from most general to most specific: 1. gametic isolation 2. reproductive isolating mechanism 3. pollen-stigma incompatibility 4. prezygotic isolating mechanism A) 2, 3, 1, 4 B) 2, 4, 1, 3 C) 4, 1, 2, 3 D) 4, 2, 1, 3 E) 2, 1, 4, 3
Answer: B
15) Referring to a plant sexual life cycle, which of the following terms describes the process that leads directly to the formation of gametes? A) Sporophyte meiosis B) Gametophyte mitosis C) Gametophyte meiosis D) Sporophyte mitosis E) Alternation of generations
Answer: B
16) If there are 20 centromeres in a cell at anaphase, how many chromosomes are there in each daughter cell following cytokinesis? A) 10 B) 20 C) 30 D) 40 E) 80
Answer: B
16) Rank the following 1-base point mutations (from most likely to least likely) with respect to their likelihood of affecting the structure of the corresponding polypeptide: 1. insertion mutation deep within an intron 2. substitution mutation at the 3rd position of an exonic codon 3. substitution mutation at the 2nd position of an exonic codon 4. deletion mutation within the first exon of the gene A) 1, 2, 3, 4 B) 4, 3, 2, 1 C) 2, 1, 4, 3 D) 3, 1, 4, 2 E) 2, 3, 1, 4
Answer: B
16) The reaction -center chlorophyll of photosystem I is known as P700 because A) there are 700 chlorophyll molecules in the center. B) this pigment is best at absorbing light with a wavelength of 700 nm. C) there are 700 photosystem I components to each chloroplast. D) it absorbs 700 photons per microsecond. E) the plastoquinone reflects light with a wavelength of 700 nm.
Answer: B
16) Which of the following is an example of alternation of generations? A) A grandparent and grandchild each has dark hair, but the parent has blond hair. B) A diploid plant (sporophyte) produces, by meiosis, a spore that gives rise to a multicellular, haploid pollen grain (gametophyte). C) A diploid animal produces gametes by meiosis, and the gametes undergo fertilization to produce a diploid zygote. D) A haploid mushroom produces gametes by mitosis, and the gametes undergo fertilization, which is immediately followed by meiosis. E) A diploid cell divides by mitosis to produce two diploid daughter cells, which then fuse to produce a tetraploid cell.
Answer: B
16) Which of the following is true for all exergonic reactions? A) The products have more total energy than the reactants. B) The reaction proceeds with a net release of free energy. C) Some reactants will be converted to products. D) A net input of energy from the surroundings is required for the reactions to proceed. E) The reactions are nonspontaneous.
Answer: B
16) Which of the following statements concerning prokaryotic and eukaryotic cells is not correct? A) Prokaryotic cells lack a membrane-bound nucleus. B) Prokaryotic cells contain small membrane-enclosed organelles. C) Eukaryotic cells contain a membrane-bound nucleus. D) DNA, or deoxyribonucleic acid, is present in both prokaryotic cells and eukaryotic cells. E) DNA or deoxyribonucleic acid is present in the nucleus of eukaryotic cells.
Answer: B
17) Barbara McClintock, famous for discovering that genes could move within genomes, had her meticulous work ignored for nearly 4 decades, but eventually won the Nobel Prize. Why was her work so distrusted? A) The work of women scientists was still not allowed to be published. B) Geneticists did not want to lose their cherished notions of DNA stability. C) There were too many alternative explanations for transposition. D) She allowed no one else to duplicate her work. E) She worked only with maize, which was considered ʺmerelyʺ a plant.
Answer: B
17) How many of their daughters might be expected to be color -blind dwarfs? A) All B) None C) Half D) One out of four E) Three out of four
Answer: B
17) Testosterone functions inside a cell by A) acting as a signal receptor that activates ion-channel proteins. B) binding with a receptor protein that enters the nucleus and activates specific genes. C) acting as a steroid signal receptor that activates ion -channel proteins. D) becoming a second messenger that inhibits adenylyl cyclase. E) coordinating a phosphorylation cascade that increases glycogen metabolism.
Answer: B
17) Why do RNA viruses appear to have higher rates of mutation? A) RNA nucleotides are more unstable than DNA nucleotides. B) Replication of their genomes does not involve the proofreading steps of DNA replication. C) RNA viruses replicate faster. D) RNA viruses can incorporate a variety of nonstandard bases. E) RNA viruses are more sensitive to mutagens.
Answer: B
4) Which of the following has not yet been synthesized in laboratory experiments studying the origin of life? A) liposomes B) liposomes with selectively permeable membranes C) oligopeptides and other oligomers D) protobionts that use DNA to program protein synthesis E) amino acids
Answer: D
18) Under which of the following conditions would you expect to find a cell with a predominance of free ribosomes? A) a cell that is secreting proteins B) a cell that is producing cytoplasmic enzymes C) a cell that is constructing its cell wall or extracellular matrix D) a cell that is digesting food particles E) a cell that is enlarging its vacuole
Answer: B
18) Which mutation should least require realignment of homologous regions of a gene that is common to several related species? A) 3-base insertion B) 1-base substitution C) 4-base insertion D) 1-base deletion E) 3-base deletion
Answer: B
18) Which of the following represents an idea that Darwin learned from the writings of Thomas Malthus? A) All species are fixed in the form in which they are created. B) Populations tend to increase at a faster rate than their food supply normally allows. C) Earth changed over the years through a series of catastrophic upheavals. D) The environment is responsible for natural selection. E) Earth is more than 10,000 years old.
Answer: B
19) An animal cell lacking oligosaccharides on the external surface of its plasma membrane would likely be impaired in which function? A) transporting ions against an electrochemical gradient B) cell-cell recognition C) maintaining fluidity of the phospholipid bilayer D) attaching to the cytoskeleton E) establishing the diffusion barrier to charged molecules
Answer: B
19) When glucose monomers are joined together by glycosidic linkages to form a cellulose polymer, the changes in free energy, total energy, and entropy are as follows: A) +△G, +△H, +△S B) +△G, +△H, -△S C) +△G, -△H, -△S D) -△G, +△H, +△S E) -△G, -△H, -△S
Answer: B
19) Which of the following are directly associated with photosystem I? A) harvesting of light energy by ATP B) receiving electrons from plastocyanin C) P680 reaction-center chlorophyll D) extraction of hydrogen electrons from the splitting of water E) passing electrons to plastoquinone
Answer: B
19) Within the body of an HIV- infected individual who is being treated with a single NA, and whose HIV particles are currently vulnerable to this NA, which of these situations can increase the virusʹ relative fitness? 1. mutations resulting in RTs with decreased rates of nucleotide mismatch 2. mutations resulting in RTs with increased rates of nucleotide mismatch 3. mutations resulting in RTs that have proofreading capability A) 1 only B) 2 only C) 3 only D) 1 and 3 E) 2 and 3
Answer: B
2) Compared with 31P, the radioactive isotope 32P has A) a different atomic number. B) one more neutron. C) one more proton. D) one more electron. E) a different charge.
Answer: B
2) In his transformation experiments, what did Griffith observe? A) Mutant mice were resistant to bacterial infections. B) Mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic form. C) Mixing a heat-killed nonpathogenic strain of bacteria with a living pathogenic strain makes the pathogenic strain nonpathogenic. D) Infecting mice with nonpathogenic strains of bacteria makes them resistant to pathogenic strains. E) Mice infected with a pathogenic strain of bacteria can spread the infection to other mice.
Answer: B
2) The molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction A) gains electrons and gains energy. B) loses electrons and loses energy. C) gains electrons and loses energy. D) loses electrons and gains energy. E) neither gains nor loses electrons, but gains or loses energy.
Answer: B
2) The slight negative charge at one end of one water molecule is attracted to the slight positive charge of another water molecule. What is this attraction called? A) a covalent bond B) a hydrogen bond C) an ionic bond D) a hydrophilic bond E) a hydrophobic bond
Answer: B
2) What is a chromatid? A) a chromosome in G1 of the cell cycle B) a replicate chromosome C) a chromosome found outside the nucleus D) a special region that holds two centromeres together E) another name for the chromosomes found in genetics
Answer: B
2) Which of the following is true of the mating signal transduction pathway in yeast? A) The pathway carries an electrical signal between mating cell types. B) Mating type a secretes a signal called a factor. C) The molecular details of the pathway in yeast and in animals are very different. D) Scientists think the pathway evolved long after multicellular creatures appeared on Earth. E) The signal reception, transduction, and response occur in the nucleus.
Answer: B
2) Which of the following sequences correctly represents the flow of electrons during photosynthesis? A) NADPH → O2 → CO2 B) H2O → NADPH → Calvin cycle C) NADPH → chlorophyll → Calvin cycle D) H2O → photosystem I → photosystem II E) NADPH → electron transport chain → O2
Answer: B
2) Which of the following would not be true of cDNA produced using human brain tissue as the starting material? A) It could be amplified by the polymerase chain reaction. B) It could be used to create a complete genomic library. C) It is produced from mRNA using reverse transcriptase. D) It could be used as a probe to detect genes expressed in the brain. E) It lacks the introns of the human genes.
Answer: B
2) Which structure is not part of the endomembrane system? A) nuclear envelope B) chloroplast C) Golgi apparatus D) plasma membrane E) ER
Answer: B
4) Which of the following most correctly describes a shotgun technique for sequencing a genome? A) genetic mapping followed immediately by sequencing B) physical mapping followed immediately by sequencing C) cloning large genome fragments into very large vectors such as YACs, followed by sequencing D) cloning several sizes of fragments into various size vectors, ordering the clones, and then sequencing them E) cloning the whole genome directly, from one end to the other
Answer: D
4) Within a few weeks of treatment with the drug 3TC, a patientʹs HIV population consists entirely of 3TC-resistant viruses. How can this result best be explained? A) HIV can change its surface proteins and resist vaccines. B) The patient must have become reinfected with 3TC -resistant viruses. C) HIV began making drug -resistant versions of reverse transcriptase in response to the drug. D) A few drug-resistant viruses were present at the start of treatment, and natural selection increased their frequency. E) The drug caused the HIV RNA to change.
Answer: D
20) In part III of Figure 13.1, the progression of events corresponds to which of the following series? A) Zygote, mitosis, gametophyte, mitosis, fertilization, zygote, mitosis B) Sporophyte, meiosis, spore, mitosis, gametophyte, mitosis, gametes, fertilization C) Fertilization, mitosis, multicellular haploid, mitosis, spores, sporophyte D) Gametophyte, meiosis, zygote, spores, sporophyte, zygote E) Meiosis, fertilization, zygote, mitosis, adult, meiosis
Answer: B
20) Once labor begins in childbirth, contractions increase in intensity and frequency until delivery. The increasing labor contractions of childbirth are an example of A) a bioinformatic system. B) positive feedback. C) negative feedback. D) feedback inhibition. E) enzymatic catalysis.
Answer: B
20) Races of humans are unlikely to evolve extensive differences in the future for which of the following reasons? I. The environment is unlikely to change. II. Human evolution is complete. III. The human races are incompletely isolated. A) I only B) III only C) I and II only D) II and III only E) I, II, and III
Answer: B
20) Some photosynthetic organisms contain chloroplasts that lack photosystem II, yet are able to survive. The best way to detect the lack of photosystem II in these organisms would be A) to determine if they have thylakoids in the chloroplasts. B) to test for liberation of O 2 in the light. C) to test for CO 2 fixation in the dark. D) to do experiments to generate an action spectrum. E) to test for production of either sucrose or starch.
Answer: B
20) Which of the following statements best describes the termination of transcription in prokaryotes? A) RNA polymerase transcribes through the polyadenylation signal, causing proteins to associate with the transcript and cut it free from the polymerase. B) RNA polymerase transcribes through the terminator sequence, causing the polymerase to fall off the DNA and release the transcript. C) RNA polymerase transcribes through an intron, and the snRNPs cause the polymerase to let go of the transcript. D) Once transcription has initiated, RNA polymerase transcribes until it reaches the end of the chromosome. E) RNA polymerase transcribes through a stop codon, causing the polymerase to stop advancing through the gene and release the mRNA.
Answer: B
21) Research indicates that Ibuprofen, a drug used to relieve inflammation and pain, is a mixture of two enantiomers; that is, molecules that A) have identical three-dimensional shapes. B) are mirror images of one another. C) lack an asymmetric carbon. D) differ in the location of their double bonds. E) differ in their electrical charge.
Answer: B
21) Sex determination in mammals is due to the SRY region of the Y chromosome. An abnormality could allow which of the following to have a male phenotype? A) Turner syndrome, 45, X B) Translocation of SRY to an autosome of a 46, XX individual C) A person with too many X chromosomes D) A person with one normal and one shortened (deleted) X E) Down syndrome, 46, XX
Answer: B
21) To introduce a particular piece of DNA into an animal cell, such as that of a mouse, you would find more probable success with which of the following methods? A) the shotgun approach B) electroporation followed by recombination C) introducing a plasmid into the cell D) infecting the mouse cell with a Ti plasmid E) transcription and translation
Answer: B
21) What is meant by the description ʺantiparallelʺ regarding the strands that make up DNA? A) The twisting nature of DNA creates nonparallel strands. B) The 5ʹ to 3ʹ direction of one strand runs counter to the 5ʹ to 3ʹ direction of the other strand. C) Base pairings create unequal spacing between the two DNA strands. D) One strand is positively charged and the other is negatively charged. E) One strand contains only purines and the other contains only pyrimidines.
Answer: B
21) What is the function of reverse transcriptase in retroviruses? A) It hydrolyzes the host cellʹs DNA. B) It uses viral RNA as a template for DNA synthesis. C) It converts host cell RNA into viral DNA. D) It translates viral RNA into proteins. E) It uses viral RNA as a template for making complementary RNA strands.
Answer: B
21) Which of the following best describes enthalpy (H)? A) the total kinetic energy of a system B) the heat content of a chemical system C) the systemʹs entropy D) the cellʹs energy equilibrium E) the condition of a cell that is not able to react
Answer: B
22) All of the following statements concerning saturated fats are true except A) They are more common in animals than in plants. B) They have multiple double bonds in the carbon chains of their fatty acids. C) They generally solidify at room temperature. D) They contain more hydrogen than saturated fats having the same number of carbon atoms. E) They are one of several factors that contribute to atherosclerosis.
Answer: B
22) In certain plants, tall is dominant to short. If a heterozygous plant is crossed with a homozygous tall plant, what is the probability that the offspring will be short? A) 1 B) 1/2 C) 1/4 D) 1/6 E) 0
Answer: B
22) RNA polymerase in a prokaryote is composed of several subunits. Most of these subunits are the same for the transcription of any gene, but one, known as sigma, varies considerably. Which of the following is the most probable advantage for the organism of such sigma switching? A) It might allow the transcription process to vary from one cell to another. B) It might allow the polymerase to recognize different promoters under certain environmental conditions. C) It could allow the polymerase to react differently to each stop codon. D) It could allow ribosomal subunits to assemble at faster rates. E) It could alter the rate of translation and of exon splicing.
Answer: B
22) The molecular mass of glucose (C 6H12O6 ) is 180 g. Which of the following procedures should you carry out to make a 0.5 M solution of glucose? A) Dissolve 0.5 g of glucose in a small volume of water, and then add more water until the total volume of solution is 1 L. B) Dissolve 90 g of glucose in a small volume of water, and then add more water until the total volume of the solution is 1 L. C) Dissolve 180 g of glucose in a small volume of water, and then add more water until the total volume of the solution is 1 L. D) Dissolve 0.5 g of glucose in 1 L of water. E) Dissolve 180 g of glucose in 1 L of water.
Answer: B
22) When an excess of the ligand (hormone) is poured through the column after the receptor binding step, what do you expect will occur? A) The ligand will attach to those beads that have the receptor and remain on the column. B) The ligand will cause the receptor to be displaced from the beads and eluted out. C) The ligand will attach to the bead instead of the receptor. D) The ligand will cause the bead to lose its affinity by changing shape. E) The reaction will cause a pH change due to electron transfer.
Answer: B
40) In an experimental situation, a student researcher inserts an mRNA molecule into a eukaryotic cell after he has removed its 5ʹ cap and poly(A) tail. Which of the following would you expect him to find? A) The mRNA could not exit the nucleus to be translated. B) The cell recognizes the absence of the tail and polyadenylates the mRNA. C) The molecule is digested by restriction enzymes in the nucleus. D) The molecule is digested by exonucleases since it is no longer protected at the 5ʹ end. E) The molecule attaches to a ribosome and is translated, but more slowly.
Answer: D
40) One possible result of chromosomal breakage is for a fragment to join a nonhomologous chromosome. What is this alteration called? A) Deletion B) Disjunction C) Inversion D) Translocation E) Duplication
Answer: D
41) A blue budgie is crossed with a white budgie. Which of the following results is not possible? A) Green offspring only B) Yellow offspring only C) Blue offspring only D) Green and yellow offspring E) a 9:3:3:1 ratio
Answer: D
41) A nonreciprocal crossover causes which of the following products? A) Deletion only B) Duplication only C) Nondisjunction D) Deletion and duplication E) Duplication and nondisjunction
Answer: D
41) In thylakoids, protons travel through ATP synthase from the stroma to the thylakoid space. Therefore the catalytic ʺknobsʺ of ATP synthase would be located A) on the side facing the thylakoid space. B) on the ATP molecules themselves. C) on the pigment molecules of PSI and PSII. D) on the stroma side of the membrane. E) built into the center of the thylkoid stack (granum).
Answer: D
41) Which curve was most likely generated from analysis of an enzyme from a human stomach where conditions are strongly acid? A) curve 1 B) curve 2 C) curve 3 D) curve 4 E) curve 5
Answer: D
23) If the HMS Beagle had completely bypassed the Galapagos Islands, Darwin would have had a much poorer understanding of the A) relative stability of a well-adapted populationʹs numbers over many generations. B) ability of populations to undergo modification as they adapt to a particular environment. C) tendency of organisms to produce the exact number of offspring that the environment can support. D) unlimited resources that support population growth in most natural environments. E) lack of genetic variation among all members of a population.
Answer: B
23) This method of affinity chromatography would be expected to collect which of the following? A) molecules of the hormone B) molecules of purified receptor C) G proteins D) assorted membrane proteins E) hormone-receptor complexes
Answer: B
23) Two true-breeding stocks of pea plants are crossed. One parent has red, axial flowers and the other has white, terminal flowers; all F1 individuals have red, axial flowers. The genes for flower color and location assort independently. If 1,000 F 2 offspring resulted from the cross, approximately how many of them would you expect to have red, terminal flowers? A) 65 B) 190 C) 250 D) 565 E) 750
Answer: B
23) Which of the following produces multiple identical copies of a gene for basic research or for large-scale production of a gene product? A) restriction enzymes B) gene cloning C) DNA ligase D) gel electrophoresis E) reverse transcriptase
Answer: B
23) Which of these is the function of a poly (A) signal sequence? A) It adds the poly (A) tail to the 3ʹ end of the mRNA. B) It codes for a sequence in eukaryotic transcripts that signals enzymatic cleavage ~10 —35 nucleotides away. C) It allows the 3ʹ end of the mRNA to attach to the ribosome. D) It is a sequence that codes for the hydrolysis of the RNA polymerase. E) It adds a 7 -methylguanosine cap to the 3ʹ end of the mRNA.
Answer: B
24) A space probe returns with a culture of a microorganism found on a distant planet. Analysis shows that it is a carbon-based life- form that has DNA. You grow the cells in 15N medium for several generations and then transfer them to 14N medium. Which pattern in Figure 16.1 would you expect if the DNA was replicated in a conservative manner?
Answer: B
24) A triploid cell contains three sets of chromosomes. If a cell of a usually diploid species with 42 chromosomes per cell is triploid, this cell would be expected to have which of the following? A) 63 chromosomes in 31 1/2 pairs B) 63 chromosomes in 21 sets of 3 C) 63 chromosomes, each with three chromatids D) 21 chromosome pairs and 21 unique chromosomes
Answer: B
24) How many grams of the molecule in Figure 3.2 would be required to make 1 L of a 0.5 M solution of the molecule? (Carbon = 12, Oxygen = 16, Hydrogen = 1) A) 29 B) 30 C) 60 D) 150 E) 342
Answer: B
24) In animal cells, hydrolytic enzymes are packaged to prevent general destruction of cellular components. Which of the following organelles functions in this compartmentalization? A) chloroplast B) lysosome C) central vacuole D) peroxisome E) glyoxysome
Answer: B
24) New combinations of linked genes are due to which of the following? A) Nondisjunction B) Crossing over C) Independent assortment D) Mixing of sperm and egg E) Deletions
Answer: B
24) Starting with one molecule of glucose, the ʺnetʺ products of glycolysis are A) 2 NAD+ , 2 H+ , 2 pyruvate, 2 ATP, and 2 H 2O. B) 2 NADH, 2 H+ , 2 pyruvate, 2 ATP, and 2 H 2O. C) 2 FADH2 , 2 pyruvate, 4 ATP, and 2 H 2O. D) 6 CO2 , 6 H2O, 2 ATP, and 2 pyruvate. E) 6 CO2 , 6 H2O, 36 ATP, and 2 citrate.
Answer: B
25) In glycolysis, for each molecule of glucose oxidized to pyruvate A) 2 molecules of ATP are used and 2 molecules of ATP are produced. B) 2 molecules of ATP are used and 4 molecules of ATP are produced. C) 4 molecules of ATP are used and 2 molecules of ATP are produced. D) 2 molecules of ATP are used and 6 molecules of ATP are produced. E) 6 molecules of ATP are used and 6 molecules of ATP are produced.
Answer: B
25) The formulation of a model for a structure or for a process serves which of the following purposes? A) It asks a scientific question. B) It functions as a testable hypothesis. C) It records observations. D) It serves as a data point among results. E) It can only be arrived at after years of experimentation.
Answer: B
25) What is a triacylglycerol? A) a protein with tertiary structure B) a lipid made with three fatty acids and glycerol C) a lipid that makes up much of the plasma membrane D) a molecule formed from three alcohols by dehydration reactions E) a carbohydrate with three sugars joined together by glycosidic linkages
Answer: B
26) Species that are in the same __________ are more closely related than species that are only in the same __________. A) phylum; class B) family; order C) class; order D) family; genus E) kingdom; phylum
Answer: B
26) Unequal crossing over during Prophase I can result in one sister chromosome with a deletion and another with a duplication. A mutated form of hemoglobin, known as hemoglobin Lepore, is known in the human population. Hemoglobin Lepore has a deleted set of amino acids. If it was caused by unequal crossing over, what would be an expected consequence? A) If it is still maintained in the human population, hemoglobin Lepore must be selected for in evolution. B) There should also be persons born with, if not living long lives with, an anti -Lepore mutation or duplication. C) Each of the genes in the hemoglobin gene family must show the same deletion. D) The deleted gene must have undergone exon shuffling E) The deleted region must be located in a different area of the individualʹs genome.
Answer: B
26) What is the most reasonable conclusion that can be drawn from the fact that the frequency of the recessive trait (aa) has not changed over time? A) The population is undergoing genetic drift. B) The two phenotypes are about equally adaptive under laboratory conditions. C) The genotype AA is lethal. D) There has been a high rate of mutation of allele A to allele a. E) There has been sexual selection favoring allele a.
Answer: B
26) Which of the following are primarily responsible for cytokinesis in plant cells? A) kinetochores B) Golgi-derived vesicles C) actin and myosin D) centrioles and basal bodies E) cyclin-dependent kinases
Answer: B
26) Which of the following describes plant virus infections? A) They can be controlled by the use of antibiotics. B) They are spread throughout a plant by passing through the plasmodesmata. C) They have little effect on plant growth. D) They are seldom spread by insects. E) They can never be inherited from a parent.
Answer: B
26) Which of the following statements is true concerning catabolic pathways? A) They combine molecules into more energy -rich molecules. B) They are usually coupled with anabolic pathways to which they supply energy in the form of ATP. C) They are endergonic. D) They are spontaneous and do not need enzyme catalysis. E) They build up complex molecules such as protein from simpler compounds.
Answer: B
42) Structures as different as human arms, bat wings, and dolphin flippers contain many of the same bones, these bones having developed from very similar embryonic tissues. How do biologists interpret these similarities? A) By identifying the bones as being homologous B) By the principle of convergent evolution C) By proposing that humans, bats, and dolphins share a common ancestor D) A and C only E) A, B, and C
Answer: D
42) The data in the graphs above indicate that A) a hybrid zone was established after the completion of the bridge. B) no interspersal of the two types of squirrel occurred after the completion of the bridge. C) gene flow occurred from one type of squirrel into the gene pool of the other type of squirrel. D) 2-way migration of squirrels occurred across the bridge, but without hybridization. E) some northern squirrels migrated south, but no southern squirrels migrated north across the bridge.
Answer: D
27) How many genes must be responsible for these coat colors in Labrador retrievers? A) 1 B) 2 C) 3 D) 4
Answer: B
27) The liver is involved in detoxification of many poisons and drugs. Which of the following structures is primarily involved in this process and therefore abundant in liver cells? A) rough ER B) smooth ER C) Golgi apparatus D) Nuclear envelope E) Transport vesicles
Answer: B
28) A compound contains hydroxyl groups as its predominant functional group. Which of the following statements is true concerning this compound? A) It lacks an asymmetric carbon, and it is probably a fat or lipid. B) It should dissolve in water. C) It should dissolve in a nonpolar solvent. D) It wonʹt form hydrogen bonds with water. E) It is hydrophobic.
Answer: B
28) The origin of a new plant species by hybridization, coupled with accidents during nuclear division, is an example of A) allopatric speciation. B) sympatric speciation. C) autopolyploidy. D) habitat selection.
Answer: B
28) Which of the following statements best describes the relationship between photosynthesis and respiration? A) Respiration is the reversal of the biochemical pathways of photosynthesis. B) Photosynthesis stores energy in complex organic molecules, while respiration releases it. C) Photosynthesis occurs only in plants and respiration occurs only in animals. D) ATP molecules are produced in photosynthesis and used up in respiration. E) Respiration is anabolic and photosynthesis is catabolic.
Answer: B
29) A water sample from a hot thermal vent contained a single -celled organism that had a cell wall but lacked a nucleus. What is its most likely classification? A) Eukarya B) Archaea C) Animalia D) Protista E) Fungi
Answer: B
29) In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of the allele a is 0.4. What is the percentage of the population that is homozygous for this allele? A) 4 B) 16 C) 32 D) 36 E) 40
Answer: B
29) Tetrads of chromosomes are aligned at the equator of the spindle; alignment determines independent assortment. A) I B) II C) IV D) VII E) VIII
Answer: B
29) What does the field often called ʺevo-devoʺ study? A) whether or not development is an evolutionary process B) how developmental processes have evolved C) whether or not all animals have developmental regulation D) whether the pattern of human development evolved early or late E) whether or not there are specific genes controlling development
Answer: B
29) What is a ribozyme? A) an enzyme that uses RNA as a substrate B) an RNA with enzymatic activity C) an enzyme that catalyzes the association between the large and small ribosomal subunits D) an enzyme that synthesizes RNA as part of the transcription process E) an enzyme that synthesizes RNA primers during DNA replication
Answer: B
3) A biochemist isolates and purifies various molecules needed for DNA replication. When she adds some DNA, replication occurs, but each DNA molecule consists of a normal strand paired with numerous segments of DNA a few hundred nucleotides long. What has she probably left out of the mixture? A) DNA polymerase B) DNA ligase C) nucleotides D) Okazaki fragments E) primase
Answer: B
3) For this pair of items, choose the option that best describes their relationship. (A) The number of cis double bonds in saturated fatty acids (B) The number of cis double bonds in unsaturated fatty acids A) Item (A) is greater than item (B). B) Item (A) is less than item (B). C) Item (A) is exactly or very approximately equal to item (B). D) Item (A) may stand in more than one of the above relations to item (B).
Answer: B
3) Viral envelopes can best be analyzed with which of the following techniques? A) transmission electron microscopy B) antibodies against specific proteins not found in the host membranes C) staining and visualization with the light microscope D) use of plaque assays for quantitative measurement of viral titer E) immunofluorescent tagging of capsid proteins
Answer: B
3) Which of the following metabolic processes can occur without a net influx of energy from some other process? A) ADP + Pi → ATP + H2O B) C6H12O6 + 6 O2 → 6 CO2 + 6H2O C) 6 CO2 + 6 H2O → C6H12O6 + 6 O2 D) amino acids → protein E) glucose + fructose → sucrose
Answer: B
30) How many electrons does nitrogen have in its valence shell? A) 2 B) 5 C) 7 D) 8 E) 14
Answer: B
30) Which of the following is a compartment that often takes up much of the volume of a plant cell? A) lysosome B) vacuole C) mitochondrion D) Golgi apparatus E) peroxisome
Answer: B
31) A hybrid zone is properly defined as A) an area where two closely related speciesʹ ranges overlap. B) an area where mating occurs between members of two closely related species, producing viable offspring. C) a zone that features a gradual change in species composition where two neighboring ecosystems border each other. D) a zone that includes the intermediate portion of a cline. E) an area where members of two closely related species intermingle, but experience no gene flow.
Answer: B
31) Antiviral drugs that have become useful are usually associated with which of the following properties? A) ability to remove all viruses from the infected host B) interference with the viral reproduction C) prevention of the host from becoming infected D) removal of viral proteins E) removal of viral mRNAs
Answer: B
31) Arrange these events from earliest to most recent. 1. emission of lava in what is now Siberia at time of Permian extinctions 2. emission of lava that solidified at the same time as iron -bearing terrestrial rocks began to rust 3. emission of lava that solidified at the same time as rusted iron precipitated from seawater 4. emission of lava in what is now India at time of Cretaceous extinctions A) 3, 1, 2, 4 B) 3, 2, 1, 4 C) 3, 1, 4, 2 D) 1, 3, 2, 4 E) 1, 2, 3, 4
Answer: B
31) In a Hardy-Weinberg population with two alleles, A and a, that are in equilibrium, the frequency of allele a is 0.2. What is the frequency of individuals with Aa genotype? A) 0.20 B) 0.32 C) 0.42 D) 0.80 E) Genotype frequency cannot be determined from the information provided.
Answer: B
31) In eukaryotes, general transcription factors A) are required for the expression of specific protein-encoding genes. B) bind to other proteins or to a sequence element within the promoter called the TATA box. C) inhibit RNA polymerase binding to the promoter and begin transcribing. D) usually lead to a high level of transcription even without additional specific transcription factors. E) bind to sequences just after the start site of transcription.
Answer: B
31) Reduction of oxygen which forms water occurs during A) photosynthesis. B) respiration. C) both photosynthesis and respiration. D) neither photosynthesis nor respiration. E) photorespiration.
Answer: B
31) Which of the five common ancestors, labeled V—Z, has been least successful in terms of the percent of its derived species that are extant? A) V B) W C) X D) Y E) Z
Answer: B
31) Which of the following ionizes completely in solution and is considered to be a strong acid? A) NaOH B) HCl C) NH3 D) H2CO3 E) CH3COOH
Answer: B
31) Which of these provides evidence of the common ancestry of all life? A) the ubiquitous use of catalysts by living systems B) the universality of the genetic code C) the structure of the nucleus D) the structure of cilia E) the structure of chloroplasts
Answer: B
33) How many electrons does an atom of sulfur have in its valence shell? A) 4 B) 6 C) 8 D) 16 E) 32
Answer: B
33) Which pair would probably have agreed with the process that is depicted by this tree? A) Cuvier and Lamarck B) Lamarck and Wallace C) Aristotle and Lyell D) Wallace and Linnaeus E) Linnaeus and Lamarck
Answer: B
33) Why are human sex hormones considered to be lipids? A) They are essential components of cell membranes. B) They are steroids, which are not soluble in water. C) They are made of fatty acids. D) They are hydrophilic compounds. E) They contribute to atherosclerosis.
Answer: B
43) How does the cell multiply its peroxisomes? A) They bud off from the ER. B) They are brought into the cell from the environment. C) They are built de novo from cytosol materials. D) They split in two after they are too large. E) The cell synthesizes hydrogen peroxide and encloses it in a membrane.
Answer: D
43) When applying the process of science, which of these is tested? A) a question B) a result C) an observation D) a prediction E) a hypothesis
Answer: D
43) Which of the following is a possible partial genotype for the son? A) IBIB B) IBIA C) ii D) IBi E) IAIA
Answer: D
44) A molecule of carbon dioxide (CO2 ) is formed when one atom of carbon (atomic number 6) is covalently bonded with two atoms of oxygen (atomic number 8). What is the total number of electrons that must be shared between the carbon atom and the oxygen atoms in order to complete the outer electron shell of all three atoms? A) 1 B) 2 C) 3 D) 4 E) 5
Answer: D
34) A mutation in which of the following parts of a gene is likely to be most damaging to a cell? A) intron B) exon C) 5ʹ UTR D) 3ʹ UTR E) All would be equally damaging.
Answer: B
34) All of the following contain amino acids except A) hemoglobin. B) cholesterol. C) antibodies. D) enzymes. E) insulin.
Answer: B
34) Evolutionary trees such as this are properly understood by scientists to be A) theories. B) hypotheses. C) laws. D) dogmas. E) facts.
Answer: B
34) Grana, thylakoids, and stroma are all components found in A) vacuoles. B) chloroplasts. C) mitochondria. D) lysosomes. E) nuclei.
Answer: B
34) Reactants capable of interacting to form products in a chemical reaction must first overcome a thermodynamic barrier known as the reactionʹs A) entropy. B) activation energy. C) endothermic level. D) heat content. E) free-energy content.
Answer: B
35) Dideoxyribonucleotide chain - termination is a method of A) cloning DNA. B) sequencing DNA. C) digesting DNA. D) synthesizing DNA. E) separating DNA fragments.
Answer: B
35) Homologous chromosomes synapse and crossing over occurs. A) The statement is true for mitosis only. B) The statement is true for meiosis I only. C) The statement is true for meiosis II only. D) The statement is true for mitosis and meiosis I. E) The statement is true for mitosis and meiosis II.
Answer: B
35) How many electrons would be expected in the outermost electron shell of an atom with atomic number 12? A) 1 B) 2 C) 4 D) 6 E) 8
Answer: B
35) Polytene chromosomes of Drosophila salivary glands each consist of multiple identical DNA strands that are aligned in parallel arrays. How could these arise? A) replication followed by mitosis B) replication without separation C) meiosis followed by mitosis D) fertilization by multiple sperm E) special association with histone proteins
Answer: B
35) Which of these individuals is most likely to be successful in an evolutionary sense? A) a reproductively sterile individual who never falls ill B) an organism that dies after 5 days of life but leaves 10 offspring, all of whom survive to reproduce C) a male who mates with 20 females and fathers 1 offspring D) an organism that lives 100 years and leaves 2 offspring, both of whom survive to reproduce E) a female who mates with 20 males and produces 1 offspring
Answer: B
44) According to the concept of punctuated equilibrium, the ʺsuddenʺ appearance of a new species in the fossil record means that A) the species is now extinct. B) speciation occurred instantaneously. C) speciation occurred in one generation. D) speciation occurred rapidly in geologic time. E) the species will consequently have a relatively short existence, compared with other species.
Answer: D
36) In a hypothetical world, every 50 years people over 6 feet tall are eliminated from the population. Based on your knowledge of natural selection, you would predict that the average height of the human population will A) remain unchanged. B) gradually decline. C) rapidly decline. D) gradually increase. E) rapidly increase.
Answer: B
36) Which of the following statements regarding enzymes is true? A) Enzymes decrease the free energy change of a reaction. B) Enzymes increase the rate of a reaction. C) Enzymes change the direction of chemical reactions. D) Enzymes are permanently altered by the reactions they catalyze. E) Enzymes prevent changes in substrate concentrations.
Answer: B
36) Which of the following would you expect to be a problem for someone with nonfunctional chloride channeling? A) inadequate secretion of mucus B) buildup of excessive secretions in organs such as lungs C) buildup of excessive secretions in glands such as the pancreas D) sweat that includes no NaCl E) mental retardation due to low salt levels in brain tissue
Answer: B
36) Why do chromosomes coil during mitosis? A) to increase their potential energy B) to allow the chromosomes to move without becoming entangled and breaking C) to allow the chromosomes to fit within the nuclear envelope D) to allow the sister chromatids to remain attached E) to provide for the structure of the centromere
Answer: B
44) If you examine side A after 3 days, you should find A) a decrease in the concentration of NaCl and glucose and an increase in the water level. B) a decrease in the concentration of NaCl, an increase in water level, and no change in the concentration of glucose. C) no net change in the system. D) a decrease in the concentration of NaCl and a decrease in the water level. E) no change in the concentration of NaCl and glucose and an increase in the water level.
Answer: D
37) Alternative RNA splicing A) is a mechanism for increasing the rate of transcription. B) can allow the production of proteins of different sizes from a single mRNA. C) can allow the production of similar proteins from different RNAs. D) increases the rate of transcription. E) is due to the presence or absence of particular snRNPs.
Answer: B
37) During a laboratory experiment, you discover that an enzyme -catalyzed reaction has a △G of -20 kcal/mol. If you double the amount of enzyme in the reaction, what will be the △G for the new reaction? A) -40 kcal/mol B) -20 kcal/mol C) 0 kcal/mol D) +20 kcal/mol E) +40 kcal/mol
Answer: B
37) In cattle, roan coat color (mixed red and white hairs) occurs in the heterozygous ( Rr) offspring of red (RR) and white (rr) homozygotes. Which of the following crosses would produce offspring in the ratio of 1 red : 2 roan : 1 white? A) red × white B) roan × roan C) white × roan D) red × roan E) The answer cannot be determined from the information provided.
Answer: B
37) Independent assortment of chromosomes occurs. A) The statement is true for mitosis only. B) The statement is true for meiosis I only. C) The statement is true for meiosis II only. D) The statement is true for mitosis and meiosis I. E) The statement is true for mitosis and meiosis II.
Answer: B
37) Which of the following statements is/are true regarding the chemical reaction illustrated in Figure 5.5? A) It is a hydrolysis reaction. B) It results in a peptide bond. C) It joins two fatty acids together. D) A and B only E) A, B, and C
Answer: B
38) Some members of a photosynthetic plant species are genetically resistant to an herbicide, while other members of the same species are not resistant to the herbicide. Which combination of events should cause the most effective replacement of the non-herbicide- resistant strain of plants by the resistant strain? 1. The presence of the herbicide in the environment 2. The absence of the herbicide from the environment 3. The maintenance of the proper conditions for one generation 4. The maintenance of the proper conditions for many generations A) 1 and 3 B) 1 and 4 C) 2 and 3 D) 2 and 4
Answer: B
38) Some photosynthetic bacteria (e.g., purple sulfur bacteria) have photosystem I but not II, while others (e.g. cyanobacteria) have both PSI and PSII. Which of the following might this observation imply? A) Photosystem II must have been selected against in some species. B) Photosystem I must be more ancestral. C) Photosystem II may have evolved to be more photoprotective. D) Cyclic flow must be more primitive than linear flow of electrons. E) Cyclic flow must be the most necessary of the two processes.
Answer: B
38) Some photosynthetic bacteria (e.g., purple sulfur bacteria) have photosystem I but not II, while others (e.g. cyanobacteria) have both PSI and PSII. Which of the following might this observation imply? A) Photosystem II must have been selected against in some species. B) Photosystem I must be more ancestral. C) Photosystem II may have evolved to be more photoprotective. D) Cyclic flow must be more primitive than linear flow of electrons. E) Cyclic flow must be the most necessary of the two processes.
Answer: B
38) The active site of an enzyme is the region that A) binds allosteric regulators of the enzyme. B) is involved in the catalytic reaction of the enzyme. C) binds the products of the catalytic reaction. D) is inhibited by the presence of a coenzyme or a cofactor.
Answer: B
38) The relationship between genes S and N is an example of A) incomplete dominance. B) epistasis. C) complete dominance. D) pleiotropy. E) codominance.
Answer: B
39) Each eukaryotic mRNA, even after post - transcriptional modification, includes 5ʹ and 3ʹ UTRs. Which are these? A) the cap and tail at each end of the mRNA B) the untranslated regions at either end of the coding sequence C) the U attachment sites for the tRNAs D) the U translation sites that signal the beginning of translation E) the U — A pairs that are found in high frequency at the ends
Answer: B
39) Polysaccharides, lipids, and proteins are similar in that they A) are synthesized from monomers by the process of hydrolysis. B) are synthesized from monomers by dehydration reactions. C) are synthesized as a result of peptide bond formation between monomers. D) are decomposed into their subunits by dehydration reactions. E) all contain nitrogen in their monomer building blocks.
Answer: B
39) What is the maximum number of electrons in the 1 s orbital of an atom? A) 1 B) 2 C) 3 D) 4 E) 5
Answer: B
39) Which of the following best describes how chromosomes move toward the poles of the spindle during mitosis? A) The chromosomes are ʺreeled inʺ by the contraction of spindle microtubules. B) Motor proteins of the kinetochores move the chromosomes along the spindle microtubules. C) Non-kinetochore spindle fibers serve to push chromosomes in the direction of the poles. D) both A and B E) A, B, and C
Answer: B
4) Adaptive radiations can be a direct consequence of four of the following five factors. Select the exception. A) vacant ecological niches B) genetic drift C) colonization of an isolated region that contains suitable habitat and few competitor species D) evolutionary innovation E) an adaptive radiation in a group of organisms (such as plants) that another group uses as food
Answer: B
4) For living organisms, which of the following is an important consequence of the first law of thermodynamics? A) The energy content of an organism is constant. B) The organism ultimately must obtain all of the necessary energy for life from its environment. C) The entropy of an organism decreases with time as the organism grows in complexity. D) Organisms are unable to transform energy. E) Life does not obey the first law of thermodynamics.
Answer: B
4) No two people are genetically identical, except for identical twins. The chief cause of genetic variation among human individuals is A) new mutations that occurred in the preceding generation. B) the reshuffling of alleles in sexual reproduction. C) genetic drift due to the small size of the population. D) geographic variation within the population. E) environmental effects.
Answer: B
4) The following scientists made significant contributions to our understanding of the structure and function of DNA. Place the scientistsʹ names in the correct chronological order, starting with the first scientist(s) to make a contribution. I. Avery, McCarty, and MacLeod II. Griffith III. Hershey and Chase IV. Meselson and Stahl V. Watson and Crick A) V, IV, II, I, III B) II, I, III, V, IV C) I, II, III, V, IV D) I, II, V, IV, III E) II, III, IV, V, I
Answer: B
4) Why does the oxidation of organic compounds by molecular oxygen to produce CO 2 and water release free energy? A) The covalent bonds in organic molecules are higher energy bonds than those in water and carbon dioxide. B) Electrons are being moved from atoms that have a lower affinity for electrons (such as C) to atoms with a higher affinity for electrons (such as O). C) The oxidation of organic compounds can be used to make ATP. D) The electrons have a higher potential energy when associated with water and CO 2 than they do in organic compounds. E) The covalent bond in O2 is unstable and easily broken by electrons from organic molecules.
Answer: B
40) Carbon dioxide (CO2 ) is released during which of the following stages of cellular respiration? A) glycolysis and the oxidation of pyruvate to acetyl CoA B) oxidation of pyruvate to acetyl CoA and the citric acid cycle C) the citric acid cycle and oxidative phosphorylation D) oxidative phosphorylation and fermentation E) fermentation and glycolysis
Answer: B
40) Carotenoids are often found in foods that are considered to have antioxidant properties in human nutrition. What related function do they have in plants? A) They serve as accessory pigments. B) They dissipate excessive light energy. C) They cover the sensitive chromosomes of the plant. D) They reflect orange light. E) They take up toxins from the water.
Answer: B
40) Carotenoids are often found in foods that are considered to have antioxidant properties in human nutrition. What related function do they have in plants? A) They serve as accessory pigments. B) They dissipate excessive light energy. C) They cover the sensitive chromosomes of the plant. D) They reflect orange light. E) They take up toxins from the water.
Answer: B
40) In which population would it be least likely that an accident would significantly alter the frequency of the brown allele? A) Population A. B) Population B. C) Population C. D) They are all the same. E) It is impossible to tell from the information given.
Answer: B
40) RNAi methodology uses double -stranded pieces of RNA to trigger a breakdown or blocking of mRNA. For which of the following might it more possibly be useful? A) to raise the rate of production of a needed digestive enzyme B) to decrease the production from a harmful gain -of- function mutated gene C) to destroy an unwanted allele in a homozygous individual D) to form a knockout organism that will not pass the deleted sequence to its progeny E) to raise the concentration of a desired protein
Answer: B
41) If the low number of hybrid flies in the hybrid zone, relative to the number of D. santomea flies there, is due to the fact that hybrids are poorly adapted to conditions in the hybrid zone, and if fewer hybrid flies are produced with the passage of time, this is most likely to lead to A) fusion. B) reinforcement. C) stability. D) further speciation events.
Answer: B
41) If two modern organisms are distantly related in an evolutionary sense, then one should expect that A) they live in very different habitats. B) they should share fewer homologous structures than two more closely related organisms. C) their chromosomes should be very similar. D) they shared a common ancestor relatively recently. E) they should be members of the same genus.
Answer: B
41) What is a hypothesis? A) the same thing as an unproven theory B) a tentative explanation that can be tested and is falsifiable C) a verifiable observation sensed directly, or sensed indirectly with the aid of scientific instrumentation D) a fact based on qualitative data that is testable E) a fact based on quantitative data that is falsifiable
Answer: B
41) Which of the following questions might be answered by such a method? A) How many cells are produced by the culture per hour? B) What is the length of the S phase of the cell cycle? C) When is the S chromosome synthesized? D) How many picograms of DNA are made per cell cycle? E) When do spindle fibers attach to chromosomes?
Answer: B
42) Which of the following experimental procedures is most likely to hasten mRNA degradation in a eukaryotic cell? A) enzymatic shortening of the poly(A) tail B) removal of the 5ʹ cap C) methylation of C nucleotides D) memethylation of histones E) removal of one or more exons
Answer: B
43) Anatomically, what was true of Lystrosaurus? A) Its jaw would have been hinged the same way as the jaws of the early reptiles were hinged. B) It was a tetrapod. C) It had thin, moist skin without scales. D) Its dentition (tooth pattern) was typical of modern mammals. E) It would have had no temporal fenestra in its skull.
Answer: B
43) At the beginning of the experiment, A) side A is hypertonic to side B. B) side A is hypotonic to side B. C) side A is isotonic to side B. D) side A is hypertonic to side B with respect to glucose. E) side A is hypotonic to side B with respect to sodium chloride.
Answer: B
43) Cellular respiration harvests the most chemical energy from which of the following? A) substrate- level phosphorylation B) chemiosmotic phosphorylation C) converting oxygen to ATP D) transferring electrons from organic molecules to pyruvate E) generating carbon dioxide and oxygen in the electron transport chain
Answer: B
43) If mammalian cells receive a go-ahead signal at the G1 checkpoint, they will A) move directly into telophase. B) complete the cycle and divide. C) exit the cycle and switch to a nondividing state. D) show a drop in MPF concentration. E) complete cytokinesis and form new cell walls.
Answer: B
43) What is the maximum number of covalent bonds an element with atomic number 8 can make with hydrogen? A) 1 B) 2 C) 3 D) 4 E) 6
Answer: B
43) Which is a carbonyl functional group?
Answer: B
44) In 1997, Dolly the sheep was cloned. Which of the following processes was used? A) use of mitochondrial DNA from adult female cells of another ewe B) replication and dedifferentiation of adult stem cells from sheep bone marrow C) separation of an early stage sheep blastula into separate cells, one of which was incubated in a surrogate ewe D) fusion of an adult cellʹs nucleus with an enucleated sheep egg, followed by incubation in a surrogate E) isolation of stem cells from a lamb embryo and production of a zygote equivalent
Answer: D
44) During aerobic respiration, electrons travel downhill in which sequence? A) food → citric acid cycle → ATP → NAD+ B) food → NADH → electron transport chain → oxygen C) glucose → pyruvate → ATP → oxygen D) glucose → ATP → electron transport chain → NADH E) food → glycolysis → citric acid cycle → NADH → ATP
Answer: B
44) Which of the following pieces of evidence most strongly supports the common origin of all life on Earth? A) All organisms require energy. B) All organisms use essentially the same genetic code. C) All organisms reproduce. D) All organisms show heritable variation. E) All organisms have undergone evolution.
Answer: B
44) Motor proteins provide for molecular motion in cells by interacting with what types of cellular structures? A) sites of energy production in cellular respiration B) membrane proteins C) ribosomes D) cytoskeletons E) cellulose fibers in the cell wall
Answer: D
45) Abnormal chromosomes are frequent in malignant tumors. Errors such as translocations may place a gene in close proximity to different control regions. Which of the following might then occur to make the cancer worse? A) An increase in non-disjunction B) Expression of inappropriate gene products C) A decrease in mitotic frequency D) Death of the cancer cells in the tumor E) Sensitivity of the immune system
Answer: B
45) Which of the following best describes the addition of nucleotides to a growing DNA chain? A) A nucleoside triphosphate is added to the 5ʹ end of the DNA, releasing a molecule of pyrophosphate. B) A nucleoside triphosphate is added to the 3ʹ end of the DNA, releasing a molecule of pyrophosphate. C) A nucleoside diphosphate is added to the 5ʹ end of the DNA, releasing a molecule of phosphate. D) A nucleoside diphosphate is added to the 3ʹ end of the DNA, releasing a molecule of phosphate. E) A nucleoside monophosphate is added to the 5ʹ end of the DNA.
Answer: B
45) Which of the following occurs in meiosis but not in mitosis? A) Chromosome replication B) Synapsis of chromosomes C) Production of daughter cells D) Alignment of chromosomes at the equator E) Condensation of chromatin
Answer: B
44) Which of the following is a possible genotype for the mother? A) IAIA B) IBIB C) ii D) IAi E) IAIB
Answer: D
44) Which of the following is true of enzymes? A) Enzymes may require a nonprotein cofactor or ion for catalysis to take speed up more appreciably than if the enzymes act alone. B) Enzyme function is increased if the three -dimensional structure or conformation of an enzyme is altered. C) Enzyme function is independent of physical and chemical environmental factors such as pH and temperature. D) Enzymes increase the rate of chemical reaction by lowering activation energy barriers.
Answer: D
46) Reproductive cloning of human embryos is generally considered unethical. However, on the subject of therapeutic cloning there is a wider divergence of opinion. Which of the following is a likely explanation? A) Use of adult stem cells is likely to produce more cell types than use of embryonic stem cells. B) Cloning to produce embryonic stem cells may lead to great medical benefits for many. C) Cloning to produce stem cells relies on a different initial procedure than reproductive cloning. D) A clone that lives until the blastocyst stage does not yet have human DNA. E) No embryos would be destroyed in the process of therapeutic cloning.
Answer: B
46) The tRNA shown in Figure 17.4 has its 3ʹ end projecting beyond its 5ʹ end. What will occur at this 3ʹ end? A) The codon and anticodon complement one another. B) The amino acid binds covalently. C) The excess nucleotides (ACCA) will be cleaved off at the ribosome. D) The small and large subunits of the ribosome will attach to it. E) The 5ʹ cap of the mRNA will become covalently bound.
Answer: B
44) Which of the following statements is true about buffer solutions? A) They maintain a constant pH when bases are added to them but not when acids are added to them. B) They maintain a constant pH when acids are added to them but not when bases are added to them. C) They maintain a constant pH of exactly 7 in all living cells and biological fluids. D) They maintain a relatively constant pH when either acids or bases are added to them. E) They are found only in living systems and biological fluids.
Answer: D
44) Which of the substances below is a protein that can hold several other relay proteins as it binds to an activated membrane receptor? A) active transcription factor B) third messenger C) ligand D) scaffolding protein E) protein kinase
Answer: D
45) At the beginning of this century there was a general announcement regarding the sequencing of the human genome and the genomes of many other multicellular eukaryotes. There was surprise expressed by many that the number of protein -coding sequences is much smaller than they had expected. Which of the following accounts for most of the rest? A) ʺjunkʺ DNA that serves no possible purpose B) rRNA and tRNA coding sequences C) DNA that is translated directly without being transcribed D) non-protein coding DNA that is transcribed into several kinds of small RNAs with biological function E) non-protein coding DNA that is transcribed into several kinds of small RNAs without biological function
Answer: D
45) Figure 17.4 represents tRNA that recognizes and binds a particular amino acid (in this instance, phenylalanine). Which codon on the mRNA strand codes for this amino acid? A) UGG B) GUG C) GUA D) UUC E) CAU
Answer: D
45) What causes the decrease in the amount of cyclin at a specific point in the cell cycle? A) an increase in production once the restriction point is passed B) the cascade of increased production once its protein is phosphorylated by Cdk C) the changing ratio of cytoplasm to genome D) its destruction by a process initiated by the activity of its complex with a cyclin E) the binding of PDGF to receptors on the cell surface
Answer: D
45) Which of the following statements correctly describes the normal tonicity conditions for typical plant and animal cells? A) The animal cell is in a hypotonic solution, and the plant cell is in an isotonic solution. B) The animal cell is in an isotonic solution, and the plant cell is in a hypertonic solution. C) The animal cell is in a hypertonic solution, and the plant cell is in an isotonic solution. D) The animal cell is in an isotonic solution, and the plant cell is in a hypotonic solution. E) The animal cell is in a hypertonic solution, and the plant cell is in a hypotonic solution.
Answer: D
45) Zinc, an essential trace element for most organisms, is present in the active site of the enzyme carboxypeptidase. The zinc most likely functions as a(n) A) competitive inhibitor of the enzyme. B) noncompetitive inhibitor of the enzyme. C) allosteric activator of the enzyme. D) cofactor necessary for enzyme activity. E) coenzyme derived from a vitamin.
Answer: D
46) Which of the following is the probable genotype for the mother? A) IAIARR B) IAIARr C) IAirr D) IAiRr E) IAiRR
Answer: D
47) At puberty, an adolescent female body changes in both structure and function of several organ systems, primarily under the influence of changing concentrations of estrogens and other steroid hormones. How can one hormone, such as estrogen, mediate so many effects? A) Estrogen is produced in very large concentration and therefore diffuses widely. B) Estrogen has specific receptors inside several cell types, but each cell responds in the same way to its binding. C) Estrogen is kept away from the surface of any cells not able to bind it at the surface. D) Estrogen binds to specific receptors inside many kinds of cells, each of which have different responses to its binding. E) Estrogen has different shaped receptors for each of several cell types.
Answer: D
47) Produces NADH A) light reactions alone B) the Calvin cycle alone C) both the light reactions and the Calvin cycle D) neither the light reactions nor the Calvin cycle E) occurs in the chloroplast but is not part of photosynthesis
Answer: D
47) Which is a basic functional group that can accept H + and become positively charged?
Answer: D
47) Which of the following contain the 9 + 2 arrangement of microtubules? A) cilia B) centrioles C) flagella D) A and C only E) A, B, and C
Answer: D
48) Which of the following describes the function of an enzyme known as Dicer? A) It degrades single-stranded DNA. B) It degrades single-stranded mRNA. C) It degrades mRNA with no poly(A) tail. D) It trims small double-stranded RNAs into molecules that can block translation. E) It chops up single-stranded DNAs from infecting viruses.
Answer: D
47) A mutant bacterial cell has a defective aminoacyl synthetase that attaches a lysine to tRNAs with the anticodon AAA instead of a phenylalanine. The consequence of this for the cell will be that A) none of the proteins in the cell will contain phenylalanine. B) proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU. C) the cell will compensate for the defect by attaching phenylalanine to tRNAs with lysine-specifying anticodons. D) the ribosome will skip a codon every time a UUU is encountered. E) None of the above will occur; the cell will recognize the error and destroy the tRNA.
Answer: B
47) Members of two different species possess a similar- looking structure that they use in a similar fashion to perform the same function. Which information would best help distinguish between an explanation based on homology versus one based on convergent evolution? A) The two species live at great distance from each other. B) The two species share many proteins in common, and the nucleotide sequences that code for these proteins are almost identical. C) The sizes of the structures in adult members of both species are similar in size. D) Both species are well adapted to their particular environments. E) Both species reproduce sexually.
Answer: B
47) Which of the following is true of embryonic stem cells but not of adult stem cells? A) They can differentiate into many cell types. B) They make up the majority of cells of the tissue from which they are derived. C) They can continue to replicate for an indefinite period. D) They can provide enormous amounts of information about the process of gene regulation. E) One aim of using them is to provide cells for repair of diseased tissue.
Answer: B
48) An inversion in a human chromosome often results in no demonstrable phenotypic effect in the individual. What else may occur? A) There may be deletions later in life. B) Some abnormal gametes may be formed. C) There is an increased frequency of mutation. D) All inverted chromosomes are deleted. E) The individual is more likely to get cancer.
Answer: B
48) The primary role of oxygen in cellular respiration is to A) yield energy in the form of ATP as it is passed down the respiratory chain. B) act as an acceptor for electrons and hydrogen, forming water. C) combine with carbon, forming CO 2 . D) combine with lactate, forming pyruvate. E) catalyze the reactions of glycolysis.
Answer: B
48) There are 61 mRNA codons that specify an amino acid, but only 45 tRNAs. This is best explained by the fact that A) some tRNAs have anticodons that recognize four or more different codons. B) the rules for base pairing between the third base of a codon and tRNA are flexible. C) many codons are never used, so the tRNAs that recognize them are dispensable. D) the DNA codes for all 61 tRNAs but some are then destroyed. E) competitive exclusion forces some tRNAs to be destroyed by nucleases.
Answer: B
48) Tubulin is a dimer, made up of 2 slightly different polypeptides, alpha and beta. Given the structure above, what is the most likely consequence to the structure of the microtubule? A) One ʺhalf-pipeʺ side of the tubule must be heavier in alpha and the other in beta subunits. B) One end of a microtubule can grow or release dimers at a faster rate than the other. C) Microtubules grow by adding a complete circular layer at a time rather than spiraling. D) Microtubules in cilia must never grow or become shorter. E) Tubulin molecules themselves must be rigid structures.
Answer: B
48) What maintains the secondary structure of a protein? A) peptide bonds B) hydrogen bonds C) disulfide bonds D) ionic bonds E) phosphodiester bonds
Answer: B
48) Which line or lines represent(s) bags that contain a solution that is hypertonic at the end of 60 minutes? A) A and B B) B C) C D) D E) D and E
Answer: B
48) Which of the following terms best describes the reaction? A) endergonic B) exergonic C) anabolic D) allosteric E) nonspontaneous
Answer: B
49) A tetrad includes which of the following sets of DNA strands? A) Two single-stranded chromosomes that have synapsed B) Two sets of sister chromatids that have synapsed C) Four sets of sister chromatids D) Four sets of unique chromosomes E) Eight sets of sister chromatids
Answer: B
49) Produces three-carbon sugars A) light reactions alone B) the Calvin cycle alone C) both the light reactions and the Calvin cycle D) neither the light reactions nor the Calvin cycle E) occurs in the chloroplast but is not part of photosynthesis
Answer: B
49) There are at least a dozen known species in the extinct genus Lystrosaurus. If each species was suited to a quite different environment, then this relatively large number of species is likely due to A) sexual selection. B) adaptive radiation. C) heterochrony. D) polyploidy. E) species selection.
Answer: B
49) Which describes the ABO blood group system? A) Incomplete dominance B) Multiple alleles C) Pleiotropy D) Epistasis
Answer: B
49) Which of the following statements is consistent with the results? A) B is the child of A and C. B) C is the child of A and B. C) D is the child of B and C. D) A is the child of B and C. E) A is the child of C and D.
Answer: B
5) A phylogenetic tree that is ʺrootedʺ is one A) that extends back to the origin of life on Earth. B) at whose base is located the common ancestor of all taxa depicted on that tree. C) that illustrates the rampant gene swapping that occurred early in lifeʹs history. D) that indicates our uncertainty about the evolutionary relationships of the taxa depicted on the tree. E) with very few branch points.
Answer: B
5) Based on Figure 7.19 in your textbook, which of these experimental treatments would increase the rate of sucrose transport into the cell? A) decreasing extracellular sucrose concentration B) decreasing extracellular pH C) decreasing cytoplasmic pH D) adding an inhibitor that blocks the regeneration of ATP E) adding a substance that makes the membrane more permeable to hydrogen ions
Answer: B
49) Over the course of evolutionary time, what should occur? A) Methylated DNA should become fixed in the gene pools of bacterial species. B) Nonmethylated DNA should become fixed in the gene pools of bacteriophages. C) Methylated DNA should become fixed in the gene pools of bacteriophages. D) Methylated and nonmethylated strains should be maintained among both bacteria and bacteriophages, with ratios that vary over time. E) Both A and B are correct.
Answer: D
49) The termination phase of cell signaling requires which of the following? A) removal of the receptor B) activation of a different set of relay molecules C) converting ATP to camp D) reversing the binding of signal molecule to the receptor E) apoptosis
Answer: D
49) Which of the following help to hold the DNA strands apart while they are being replicated? A) primase B) ligase C) DNA polymerase D) single-strand binding proteins E) exonuclease
Answer: D
49) Which of the following is a protein synthesized at specific times during the cell cycle that associates with a kinase to form a catalytically active complex? A) PDGF B) MPF C) protein kinase D) cyclin E) Cdk
Answer: D
49) Which of the following represents the △G of the reaction? A) a B) b C) c D) d E) e
Answer: D
49) Which type of interaction stabilizes the alpha (α) helix and the beta (β) pleated sheet structures of proteins? A) hydrophobic interactions B) nonpolar covalent bonds C) ionic bonds D) hydrogen bonds E) peptide bonds
Answer: D
49) You are working on a team that is designing a new drug. In order for this drug to work, it must enter the cytoplasm of specific target cells. Which of the following would be a factor that determines whether the molecule enters the cell? A) blood or tissue type of the patient B) non-polarity of the drug molecule C) lack of charge on the drug molecule D) similarity of the drug molecule to other molecules transported by the target cells E) lipid composition of the target cellsʹ plasma membrane
Answer: D
5) For a newly evolving protist, what would be the advantage of using eukaryote - like cell division rather than binary fission? A) Binary fission would not allow for the formation of new organisms. B) Cell division would allow for the orderly and efficient segregation of multiple linear chromosomes. C) Cell division would be faster than binary fission. D) Cell division allows for lower rates of error per chromosome replication. E) Binary fission would not allow the organism to have complex cells.
Answer: B
5) From the perspective of the cell receiving the message, the three stages of cell signaling are A) the paracrine, local, and synaptic stages. B) signal reception, signal transduction, and cellular response. C) signal reception, nucleus disintegration, and new cell generation. D) the alpha, beta, and gamma stages. E) signal reception, cellular response, and cell division.
Answer: B
5) In analyzing the number of different bases in a DNA sample, which result would be consistent with the base -pairing rules? A) A = G B) A + G = C + T C) A + T = G + T D) A = C E) G = T
Answer: B
5) In what way were conditions on the early Earth of more than 3 billion years ago different from those on todayʹs Earth? A) Only early Earth had water vapor in its atmosphere. B) Only early Earth was intensely bombarded by large space debris. C) Only early Earth had an oxidizing atmosphere. D) Less ultraviolet radiation penetrated Earthʹs early atmosphere. E) Earthʹs early atmosphere had significant quantities of ozone.
Answer: B
5) What was the most significant conclusion that Gregor Mendel drew from his experiments with pea plants? A) There is considerable genetic variation in garden peas. B) Traits are inherited in discrete units, and are not the results of ʺblending.ʺ C) Recessive genes occur more frequently in the F1 than do dominant ones. D) Genes are composed of DNA. E) An organism that is homozygous for many recessive traits is at a disadvantage.
Answer: B
5) Which of the following is present in a prokaryotic cell? A) mitochondrion B) ribosome C) nuclear envelope D) chloroplast E) ER
Answer: B
50) In which of the following would there be the greatest need for osmoregulation? A) an animal connective tissue cell bathed in isotonic body fluid B) a terrestrial animal such as a snake C) a red blood cell surrounded by plasma D) a lymphocyte before it has been taken back into lymph fluid E) a plant being grown hydroponically (in a watery mixture of designated nutrients)
Answer: B
50) Monkeys of South and Central America have prehensile tails, meaning that their tails can be used to grasp objects. The tails of African and Asian monkeys are not prehensile. Which discipline is most likely to provide an evolutionary explanation for how this difference in tails came about? A) Aerodynamics B) Biogeography C) Physiology D) Biochemistry E) Botany
Answer: B
50) Requires CO2 A) light reactions alone B) the Calvin cycle alone C) both the light reactions and the Calvin cycle D) neither the light reactions nor the Calvin cycle E) occurs in the chloroplast but is not part of photosynthesis
Answer: B
50) The α helix and the β pleated sheet are both common polypeptide forms found in which level of protein structure? A) primary B) secondary C) tertiary D) quaternary E) all of the above
Answer: B
50) Which molecules contain a carbonyl group? A) A and B B) B and C C) C and D D) D and E E) E and A
Answer: B
50) Which of the following statements is most likely true? A) D is the child of A and C. B) D is the child of A and B. C) D is the child of B and C. D) A is the child of C and D. E) B is the child of A and C.
Answer: B
50) Why has C. elegans proven to be a useful model for understanding apoptosis? A) The animal has very few genes, so that finding those responsible is easier than in a more complex organism. B) The nematode undergoes a fixed and easy - to-visualize number of apoptotic events during its normal development. C) This plant has a long-studied aging mechanism that has made understanding its death just a last stage. D) While the organism ages, its cells die progressively until the whole organism is dead. E) All of its genes are constantly being expressed so all of its proteins are available from each cell.
Answer: B
51) Choose the answer that has these events of protein synthesis in the proper sequence. 1. An aminoacyl- tRNA binds to the A site. 2. A peptide bond forms between the new amino acid and a polypeptide chain. 3. tRNA leaves the P site, and the P site remains vacant. 4. A small ribosomal subunit binds with mRNA. 5. tRNA translocates to the P site. A) 1, 3, 2, 4, 5 B) 4, 1, 2, 5, 3 C) 5, 4, 3, 2, 1 D) 4, 1, 3, 2, 5 E) 2, 4, 5, 1, 3
Answer: B
51) Which of the following triggers the cellʹs passage past the G 2 checkpoint into mitosis? A) PDGF B) MPF C) protein kinase D) cyclin E) Cdk
Answer: B
52) If an increase in dicynodont species diversity (i.e., number of species) occurred soon after the Permian extinction, and if it occurred for the same general reason usually given for the increase in mammalian diversity following the Cretaceous extinction, then it should be attributed to A) an innovation among the dicynodonts that allowed them to fill brand new niches. B) the availability of previously occupied niches. C) the extinction of the dinosaurs (except the birds). D) the evolution of humans.
Answer: B
52) Which of these five species originated earliest and appeared suddenly in the fossil record? A) V B) W C) X D) Y E) Z
Answer: B
53) A typical bacterial chromosome has ~4.6 million nucleotides. This supports approximately how many genes? A) 4.6 million B) 4.4 thousand C) 45 thousand D) about 400
Answer: B
53) An organism has a relatively large number of Hox genes in its genome. Which of the following is not true of this organism? A) It evolved from evolutionary ancestors that had fewer Hox genes. B) It must have multiple paired appendages along the length of its body. C) It has the genetic potential to have a relatively complex anatomy. D) At least some of its Hox genes owe their existence to gene duplication events. E) Its Hox genes cooperated to produce the positional patterns of this organism as it developed.
Answer: B
54) Bagworm moth caterpillars feed on evergreens and carry a silken case or bag around with them in which they eventually pupate. Adult female bagworm moths are larval in appearance; they lack the wings and other structures of the adult male and instead retain the appearance of a caterpillar even though they are sexually mature and can lay eggs within the bag. This is a good example of A) allometric growth. B) paedomorphosis. C) sympatric speciation. D) adaptive radiation. E) changes in homeotic genes.
Answer: B
54) Genetically engineered plants A) are more difficult to engineer than animals. B) include a transgenic rice plant that can help prevent vitamin A deficiency. C) are being rapidly developed, but traditional plant breeding programs are still the only method used to develop new plants. D) are able to fix nitrogen themselves. E) are banned throughout the world.
Answer: B
54) Studies of nucleosomes have shown that histones (except H1) exist in each nucleosome as two kinds of tetramers: one of 2 H2A molecules and 2 H2B molecules, and the other as 2 H3 and 2 H4 molecules. Which of the following is supported by this data? A) DNA can wind itself around either of the two kinds of tetramers. B) The two types of tetramers associate to form an octamer. C) DNA has to associate with individual histones before they form tetramers. D) Only H2A can form associations with DNA molecules. E) The structure of H3 and H4 molecules is not basic like that of the other histones.
Answer: B
54) You are given an experimental problem involving control of a geneʹs expression in the embryo of a particular species. One of your first questions is whether the geneʹs expression is controlled at the level of transcription or translation. Which of the following might best give you an answer? A) You explore whether there has been alternative splicing by examining amino acid sequences of very similar proteins. B) You measure the quantity of the appropriate pre -mRNA in various cell types and find they are all the same. C) You assess the position and sequence of the promoter and enhancer for this gene. D) An analysis of amino acid production by the cell shows you that there is an increase at this stage of embryonic life. E) You use an antibiotic known to prevent translation.
Answer: B
55) If the carbon atom of the incoming CO 2 molecule is labeled with a radioactive isotope of carbon, where will the radioactivity be measurable after one cycle? A) in C only B) in E only C) in C, D, and E D) in A, B, and C E) in B and C
Answer: B
55) Which molecule contains a sulfhydryl functional group?
Answer: B
56) It is possible to prepare vesicles from portions of the inner membrane of the mitochondrial components. Which one of the following processes could still be carried on by this isolated inner membrane? A) the citric acid cycle B) oxidative phosphorylation C) glycolysis and fermentation D) reduction of NAD+ E) both the citric acid cycle and oxidative phosphorylation
Answer: B
56) When does translation begin in prokaryotic cells? A) after a transcription initiation complex has been formed B) as soon as transcription has begun C) after the 5ʹ caps are converted to mRNA D) once the pre-mRNA has been converted to mRNA E) as soon as the DNA introns are removed from the template
Answer: B
57) In order to attach a particular amino acid to the tRNA molecule that will transport it, an enzyme, an aminoacyl- tRNA synthetase, is required, along with ATP. Initially, the enzyme has an active site for ATP and another for the amino acid, but it is not able to attach the tRNA. What must occur in order for the final attachment to occur? A) The ATP must first have to attach to the tRNA. B) The binding of the first two molecules must cause a 3-dimensional change that opens another active site on the enzyme. C) The hydrolysis of the ATP must be needed to allow the amino acid to bind to the synthetase. D) The tRNA molecule must have to alter its shape in order to be able to fit into the active site with the other two molecules. E) The 3ʹ end of the tRNA must have to be cleaved before it can have an attached amino acid.
Answer: B
57) When pairs of homologous chromosomes separate during anaphase I, A) the maternal chromosomes all move to the same daughter cell. B) the sister chromatids remain attached to one another. C) recombination is not yet complete. D) the synaptonemal complex is visible under the light microscope.
Answer: B
57) Which of the following relationships between cell structures and their respective functions is correct? A) cell wall: support, protection B) chloroplasts: chief sites of cellular respiration C) chromosomes: cytoskeleton of the nucleus D) ribosomes: secretion E) lysosomes: formation of ATP
Answer: B
58) If these fly species lost the ability to fly independently of each other as a result of separate mutation events in each lineage, then the flightless condition in these species could be an example of A) adaptive radiation. B) species selection. C) sexual selection. D) allometric growth. E) habitat differentiation.
Answer: B
58) Van der Waals interactions result when A) hybrid orbitals overlap. B) electrons are not symmetrically distributed in a molecule. C) molecules held by ionic bonds react with water. D) two polar covalent bonds react. E) a hydrogen atom loses an electron.
Answer: B
59) A van der Waals interaction is the weak attraction between A) the electrons of one molecule and the electrons of a nearby molecule. B) the nucleus of one molecule and the electrons of a nearby molecule. C) a polar molecule and a nearby nonpolar molecule. D) a polar molecule and a nearby molecule that is also polar. E) a nonpolar molecule and a nearby molecule that is also nonpolar.
Answer: B
59) Correns described that the inheritance of variegated color on the leaves of certain plants was determined by the maternal parent only. What phenomenon does this describe? A) Mitochondrial inheritance B) Chloroplast inheritance C) Genomic imprinting D) Infectious inheritance E) Sex- linkage
Answer: B
59) Which of the following is likely to lead to an increase in the concentration of ATP in a cell? A) an increase in a cellʹs anabolic activity B) an increase in a cellʹs catabolic activity C) an increased influx of cofactor molecules D) an increased amino acid concentration E) the cellʹs increased transport of materials to the environment
Answer: B
6) How many unique gametes could be produced through independent assortment by an individual with the genotype AaBbCCDdEE? A) 4 B) 8 C) 16 D) 32 E) 64
Answer: B
6) In trying to determine whether DNA or protein is the genetic material, Hershey and Chase made use of which of the following facts? A) DNA contains sulfur, whereas protein does not. B) DNA contains phosphorus, but protein does not. C) DNA contains nitrogen, whereas protein does not. D) DNA contains purines, whereas protein includes pyrimidines. E) RNA includes ribose, while DNA includes deoxyribose sugars.
Answer: B
6) Lipid-soluble signal molecules, such as testosterone, cross the membranes of all cells but affect only target cells because A) only target cells retain the appropriate DNA segments. B) intracellular receptors are present only in target cells. C) most cells lack the Y chromosome required. D) only target cells possess the cytosolic enzymes that transduce the testosterone. E) only in target cells is testosterone able to initiate the phosphorylation cascade leading to activated transcription factor.
Answer: B
6) The correct sequence, from the most to the least comprehensive, of the taxonomic levels listed here is A) family, phylum, class, kingdom, order, species, and genus. B) kingdom, phylum, class, order, family, genus, and species. C) kingdom, phylum, order, class, family, genus, and species. D) phylum, kingdom, order, class, species, family, and genus. E) phylum, family, class, order, kingdom, genus, and species.
Answer: B
6) The process of transduction usually begins A) when the chemical signal is released from the alpha cell. B) when the signal molecule changes the receptor protein in some way. C) after the target cell divides. D) after the third stage of cell signaling is completed. E) when the hormone is released from the gland into the blood.
Answer: B
6) What is bioinformatics? A) a technique using 3D images of genes in order to predict how and when they will be expressed B) a method that uses very large national and international databases to access and work with sequence information C) a software program available from NIH to design genes D) a series of search programs that allow a student to identify who in the world is trying to sequence a given species E) a procedure that uses software to order DNA sequences in a variety of comparable ways
Answer: B
6) What is true of the amino acids that might have been delivered to Earth within carbonaceous chondrites? A) They had the same proportion of L and D isomers as Earth does today. B) The proportion of the amino acids was similar to those produced in the Miller -Urey experiment. C) There were fewer kinds of amino acids on the chondrites than are found in living organisms today. D) They were delivered in the form of polypeptides.
Answer: B
6) Which of the following effects is produced by the high surface tension of water? A) Lakes donʹt freeze solid in winter, despite low temperatures. B) A water strider can walk across the surface of a small pond. C) Organisms resist temperature changes, although they give off heat due to chemical reactions. D) Water can act as a solvent. E) The pH of water remains exactly neutral.
Answer: B
60) If a cell were unable to produce histone proteins, which of the following would be a likely effect? A) There would be an increase in the amount of ʺsatelliteʺ DNA produced during centrifugation. B) The cellʹs DNA couldnʹt be packed into its nucleus. C) Spindle fibers would not form during prophase. D) Amplification of other genes would compensate for the lack of histones. E) Pseudogenes would be transcribed to compensate for the decreased protein in the cell.
Answer: B
60) Referring to Figure 10.3, oxygen would inhibit the CO 2 fixation reactions in A) cell I only. B) cell II only. C) neither cell I nor cell II. D) both cell I and cell II. E) cell I during the night and cell II during the day.
Answer: B
61) How does a noncompetitive inhibitor decrease the rate of an enzyme reaction? A) by binding at the active site of the enzyme B) by changing the shape of a reactant C) by changing the free energy change of the reaction D) by acting as a coenzyme for the reaction E) by decreasing the activation energy of the reaction
Answer: B
61) In which cell would you expect photorespiration? A) Cell I B) Cell II C) Cell I at night D) Cell II at night E) neither Cell I nor Cell II
Answer: B
61) Which of the following statements describes histones? A) Each nucleosome consists of two molecules of histone H1. B) Histone H1 is not present in the nucleosome bead; instead it is involved in the formation of higher- level chromatin structures. C) The carboxyl end of each histone extends outward from the nucleosome and is called a ʺhistone tail.ʺ D) Histones are found in mammals, but not in other animals or in plants. E) The mass of histone in chromatin is approximately nine times the mass of DNA.
Answer: B
61) Which of the following statements is true about stem cells? A) Stem cells can continually reproduce and are not subject to mitotic control. B) Stem cells can differentiate into specialized cells. C) Stem cells are found only in bone marrow. D) Stem cells are found only in the adult human brain. E) Stem cell DNA lacks introns.
Answer: B
62) The process of translation, whether in prokaryotes or eukaryotes, requires tRNAs, amino acids, ribosomal subunits, and which of the following? A) polypeptide factors plus ATP B) polypeptide factors plus GTP C) polymerases plus GTP D) SRP plus chaperones E) signal peptides plus release factor
Answer: B
62) What is considered to be the first evidence of differentiation in the cells of an embryo? A) cell division B) the occurrence of mRNAs for the production of tissue -specific proteins C) determination D) changes in the size and shape of the cell E) changes resulting from induction
Answer: B
62) Which of the following uses the amino acid sequences of polypeptides to predict a proteinʹs three-dimensional structure? A) X- ray crystallography B) bioinformatics C) analysis of amino acid sequence of small fragments D) NMR spectroscopy E) high-speed centrifugation
Answer: B
63) What is proton-motive force? A) the force required to remove an electron from hydrogen B) the transmembrane proton concentration gradient C) movement of hydrogen into the intermembrane space D) movement of hydrogen into the mitochondrion E) the addition of hydrogen to NAD +
Answer: B
63) Which of these fly organs, as they exist in current fly populations, best fits the description of an exaptation? A) wings B) balancing organs C) mouthparts D) thoraxes E) walking appendages
Answer: B
63) Why are C4 plants able to photosynthesize with no apparent photorespiration? A) They do not participate in the Calvin cycle. B) They use PEP carboxylase to initially fix CO2 . C) They are adapted to cold, wet climates. D) They conserve water more efficiently. E) They exclude oxygen from their tissues.
Answer: B
64) A scientist discovers a DNA-based test for the allele of a particular gene. This and only this allele, if homozygous, produces an effect that results in death at or about the time of birth. Of the following, which is the best use of this discovery? A) To screen all newborns of an at-risk population B) To design a test for identifying heterozygous carriers of the allele C) To introduce a normal allele into deficient newborns D) To follow the segregation of the allele during meiosis E) To test school-age children for the disorder
Answer: B
64) The existence of the phenomenon of exaptation is most closely associated with which of the following reasons that natural selection cannot fashion perfect organisms? A) Natural selection and sexual selection can work at cross -purposes to each other. B) Evolution is limited by historical constraints. C) Adaptations are often compromises. D) Chance events affect the evolutionary history of populations in environments that can change unpredictably.
Answer: B
64) The mechanism in which the end product of a metabolic pathway inhibits an earlier step in the pathway is known as A) metabolic inhibition. B) feedback inhibition. C) allosteric inhibition. D) noncooperative inhibition. E) reversible inhibition.
Answer: B
64) What is the term used for a protein molecule that assists in the proper folding of other proteins? A) tertiary protein B) chaperonin C) enzyme protein D) renaturing protein E) denaturing protein
Answer: B
64) Which of the following makes it necessary for animal cells, although they have no cell walls, to have intercellular junctions? A) Cell membranes do not distinguish the types of ions and molecules passing through them. B) Large molecules, especially proteins, do not readily get through one, much less two adjacent cell membranes. C) Cell- to-cell communication requires physical attachment of one cell to another. D) Maintenance of connective tissue shape requires cells to adhere to one another. E) The relative shapelessness of animal cells requires a mechanism for keeping the cells aligned.
Answer: B
65) DNAase is an enzyme that catalyzes the hydrolysis of the covalent bonds that join nucleotides together. What would first happen to DNA molecules treated with DNAase? A) The two strands of the double helix would separate. B) The phosphodiester bonds between deoxyribose sugars would be broken. C) The purines would be separated from the deoxyribose sugars. D) The pyrimidines would be separated from the deoxyribose sugars. E) All bases would be separated from the deoxyribose sugars.
Answer: B
65) Fossil evidence indicates that horses have gradually increased in size over geologic time. Which of the following terms best describes this? A) artificial selection B) directional selection C) stabilizing selection D) disruptive selection E) sexual selection
Answer: B
65) If the complex protein assemblage of the prokaryotic flagellum arose by the same general processes as those of the complex eyes of mollusks (such as squids and octopi), then A) natural selection cannot account for the rise of the prokaryotic flagellum. B) ancestral versions of this protein assemblage were either less functional, or had different functions, than modern prokaryotic flagella. C) scientists should accept the conclusion that neither eyes nor flagella could have arisen by evolution. D) we can conclude that both of these structures must have arisen through the direct action of an ʺintelligent designer.ʺ E) Both A and C are true.
Answer: B
65) Photorespiration lowers the efficiency of photosynthesis by preventing the formation of A) carbon dioxide molecules. B) 3-phosphoglycerate molecules C) ATP molecules. D) ribulose bisphosphate molecules. E) RuBP carboxylase molecules.
Answer: B
65) The MyoD protein A) can promote muscle development in all cell types. B) is a transcription factor that binds to and activates the transcription of muscle -related genes. C) was used by researchers to convert differentiated muscle cells into liver cells. D) magnifies the effects of other muscle proteins. E) is a target for other proteins that bind to it.
Answer: B
5) After mixing a heat-killed, phosphorescent strain of bacteria with a living non-phosphorescent strain, you discover that some of the living cells are now phosphorescent. Which observations would provide the best evidence that the ability to fluoresce is a heritable trait? A) DNA passed from the heat -killed strain to the living strain. B) Protein passed from the heat -killed strain to the living strain. C) The phosphorescence in the living strain is especially bright. D) Descendants of the living cells are also phosphorescent. E) Both DNA and protein passed from the heat -killed strain to the living strain.
Answer: D
5) If A, B, and C are all required for growth, a strain mutant for the gene encoding enzyme B would be capable of growing on which of the following media? A) minimal medium B) minimal medium supplemented with ʺAʺ only C) minimal medium supplemented with ʺBʺ only D) minimal medium supplemented with ʺCʺ only E) minimal medium supplemented with nutrients ʺAʺ and ʺBʺ
Answer: D
5) If the DNA content of a diploid cell in the G 1 phase of the cell cycle is x , then the DNA content of the same cell at metaphase of meiosis I would be A) 0.25x . B) 0.5x . C) x . D) 2x . E) 4x .
Answer: D
5) In any ecosystem, terrestrial or aquatic, what group(s) is (are) always necessary? A) autotrophs and heterotrophs B) producers and primary consumers C) photosynthesizers D) autotrophs E) green plants
Answer: D
5) Living organisms increase in complexity as they grow, resulting in a decrease in the entropy of an organism. How does this relate to the second law of thermodynamics? A) Living organisms do not obey the second law of thermodynamics, which states that entropy must increase with time. B) Life obeys the second law of thermodynamics because the decrease in entropy as the organism grows is balanced by an increase in the entropy of the universe. C) Living organisms do not follow the laws of thermodynamics. D) As a consequence of growing, organisms create more disorder in their environment than the decrease in entropy associated with their growth. E) Living organisms are able to transform energy into entropy.
Answer: D
5) Plant species A has a diploid number of 12. Plant species B has a diploid number of 16. A new species, C, arises as an allopolyploid from A and B. The diploid number for species C would probably be A) 12. B) 14. C) 16. D) 28. E) 56.
Answer: D
5) There is still some controversy among biologists about whether Neanderthals should be placed within the same species as modern humans, or into a separate species of their own. Most DNA sequence data analyzed so far indicate that there was probably little or no gene flow between Neanderthals and Homo sapiens. Which species concept is most applicable in this example? A) phylogenetic B) ecological C) morphological D) biological
Answer: D
5) Using Figure 17.5, identify a 5ʹ → 3ʹ sequence of nucleotides in the DNA template strand for an mRNA coding for the polypeptide sequence Phe -Pro-Lys. A) 5ʹ-UUUGGGAAA-3ʹ B) 5ʹ-GAACCCCTT-3ʹ C) 5ʹ-AAAACCTTT-3ʹ D) 5ʹ-CTTCGGGAA-3ʹ E) 5ʹ-AAACCCUUU-3ʹ
Answer: D
5) Which group is composed entirely of individuals who maintained that species are fixed (i.e., unchanging)? A) Aristotle, Cuvier, and Lamarck B) Linnaeus, Cuvier, and Lamarck C) Lyell, Linnaeus, and Lamarck D) Aristotle, Linnaeus, and Cuvier E) Hutton, Lyell, and Darwin
Answer: D
5) Which of the following is a false statement regarding DNA? A) Each chromosome has one very long DNA molecule with hundreds of thousands of genes. B) Every cell is enclosed by a membrane. C) Every cell uses DNA as its genetic information. D) All forms of life are composed of cells that have a membrane -enclosed nucleus. E) DNA is the unit of inheritance that is transmitted from parent to offspring.
Answer: D
5) Which process is most directly driven by light energy? A) creation of a pH gradient by pumping protons across the thylakoid membrane B) carbon fixation in the stroma C) reduction of NADP+ molecules D) removal of electrons from chlorophyll molecules E) ATP synthesis
Answer: D
50) A certain femaleʹs chromosomes 12 both have the blue gene and chromosomes 19 both have the long gene. As cells in her ovaries undergo meiosis, her resulting eggs (ova) may have which of the following? A) Either two chromosomes 12 with blue genes or two with orange genes B) Either two chromosomes 19 with long genes or two with short genes C) Either one blue or one orange gene in addition to either one long and one short gene D) One chromosome 12 with one blue gene and one chromosome 19 with one long gene
Answer: D
50) Individuals with the disorder xeroderma pigmentosum are hypersensitive to sunlight. This occurs because their cells have which impaired ability? A) They cannot replicate DNA. B) They cannot undergo mitosis. C) They cannot exchange DNA with other cells. D) They cannot repair thymine dimers. E) They do not recombine homologous chromosomes during meiosis.
Answer: D
50) The dicynodonts survived the mass extinction that was most closely correlated in time, if not in cause, with A) snowball Earth. B) a large (10 km) meteor striking the Earth. C) an intense period of sun-spot formation, with subsequent increase in solar radiation. D) the formation of Pangaea and lava flows that covered large portions of Pangaea. E) the pleistocene Ice Age.
Answer: D
51) A couple has a child with Down syndrome when the mother is 39 years old at the time of delivery. Which is the most probable cause? A) The woman inherited this tendency from her parents. B) One member of the couple carried a translocation. C) One member of the couple underwent nondisjunction in somatic cell production. D) One member of the couple underwent nondisjunction in gamete production.
Answer: D
51) If an individual has abnormal microtubules, due to a hereditary condition, in which organs or tissues would you expect dysfunction? A) limbs, hearts, areas with a good deal of contraction B) microvilli, alveoli, and glomeruli C) all ducts, such as those from salivary or sebaceous glands D) sperm, larynx, and trachea E) egg cells (ova), uterus, and kidneys
Answer: D
51) In chemiosmotic phosphorylation, what is the most direct source of energy that is used to convert ADP + Pi to ATP? A) energy released as electrons flow through the electron transport system B) energy released from substrate - level phosphorylation C) energy released from ATP synthase pumping hydrogen ions from the mitochondrial matrix D) energy released from movement of protons through ATP synthase E) No external source of energy is required because the reaction is exergonic.
Answer: D
51) Requires glucose A) light reactions alone B) the Calvin cycle alone C) both the light reactions and the Calvin cycle D) neither the light reactions nor the Calvin cycle E) occurs in the chloroplast but is not part of photosynthesis
Answer: D
51) Sexual dimorphism is most often a result of A) pansexual selection. B) stabilizing selection. C) intrasexual selection. D) intersexual selection. E) artificial selection.
Answer: D
51) The theory of evolution is most accurately described as A) an educated guess about how species originate. B) one possible explanation, among several scientific alternatives, about how species have come into existence. C) an opinion that some scientists hold about how living things change over time. D) an overarching explanation, supported by much evidence, for how populations change over time. E) an idea about how acquired characteristics are passed on to subsequent generations.
Answer: D
51) Which of the following are probably siblings? A) A and B B) A and C C) A and D D) C and D E) B and D
Answer: D
51) Which of the following describes the events of apoptosis? A) The cell dies, it is lysed, its organelles are phagocytized, its contents are recycled. B) Its DNA and organelles become fragmented, it dies, and it is phagocytized. C) The cell dies and the presence of its fragmented contents stimulates nearby cells to divide. D) Its DNA and organelles are fragmented, the cell shrinks and forms blebs, and the cell self-digests. E) Its nucleus and organelles are lysed, the cell enlarges and bursts.
Answer: D
52) A female with a paternal set of one orange and one long gene chromosomes and a maternal set comprised of one blue and one short gene chromosome is expected to produce which of the following types of eggs after meiosis? A) All eggs will have maternal types of gene combinations. B) All eggs will have paternal types of gene combinations. C) Half the eggs will have maternal and half will have paternal combinations. D) Each egg has 1/4 chance of having blue long, blue short, orange long, or orange short combinations. E) Each egg has a 3/4 chance of having blue long, blue short, orange long, or orange short combinations.
Answer: D
52) During breeding season, one should expect female house finches to prefer to mate with males with the brightest red feathers. Which of the following is true of this situation? A) Alleles that promote more efficient acquisition of carotenoid -containing foods by males should increase over the course of generations. B) Alleles that promote more effective deposition of carotenoid pigments in the feathers of males should increase over the course of generations. C) There should be directional selection for bright red feathers in males. D) All three of these. E) Only B and C.
Answer: D
52) Energy released by the electron transport chain is used to pump H + ions into which location? A) cytosol B) mitochondrial outer membrane C) mitochondrial inner membrane D) mitochondrial intermembrane space E) mitochondrial matrix
Answer: D
52) Gene therapy A) has proven to be beneficial to HIV patients. B) involves replacement of a defective allele in sex cells. C) cannot be used to correct genetic disorders. D) had apparent success in treating disorders involving bone marrow cells. E) is a widely accepted procedure.
Answer: D
52) The main proteases involved in apoptosis are A) ced-3 and ced-4. B) inactive. C) cytochromes. D) caspases. E) G proteins.
Answer: D
52) The researcher continues to study the reactions of the embryo to these new proteins and you hypothesize that he is most likely to see which of the following (while embryonic genes are still not being expressed)? A) The cells begin to differentiate. B) The proteins are evenly distributed throughout the embryo. C) Larval features begin to make their appearance. D) Spatial axes (anterior → posterior, etc.) begin to be determined. E) The embryo begins to lose cells due to apoptosis from no further gene expression.
Answer: D
52) The sugar that results from three ʺturnsʺ of the Calvin cycle is glyceraldehyde -3-phosphate (G3P). Which of the following is a consequence of this? A) Formation of a molecule of glucose would require 9 ʺturns.ʺ B) G3P more readily forms sucrose and other disaccharides than it does monosaccharides. C) Some plants would not taste sweet to us. D) The formation of starch in plants involves assembling many G3P molecules, with or without further rearrangements. E) G3P is easier for a plant to store.
Answer: D
52) Which of the following represents the difference between the free-energy content of the reaction and the free-energy content of the products? A) a B) b C) c D) d E) e
Answer: D
53) Chiasmata are what we see under a microscope that let us know which of the following is occurring? A) Asexual reproduction B) Meiosis II C) Anaphase II D) Crossing over E) Separation of homologs
Answer: D
53) In the process of carbon fixation, RuBP attaches a CO 2 to produce a 6 carbon molecule, which is then split in two. After phosphorylation and reduction, what more needs to happen in the Calvin cycle? A) addition of a pair of electrons from NADPH B) inactivation of RuBP carboxylase enzyme C) regeneration of ATP from ADP D) regeneration of rubisco E) a gain of NADPH
Answer: D
53) The direct energy source that drives ATP synthesis during respiratory oxidative phosphorylation is A) oxidation of glucose to CO2 and water. B) the thermodynamically favorable flow of electrons from NADH to the mitochondrial electron transport carriers. C) the final transfer of electrons to oxygen. D) the difference in H+ concentrations on opposite sides of the inner mitochondrial membrane. E) the thermodynamically favorable transfer of phosphate from glycolysis and the citric acid cycle intermediate molecules of ADP.
Answer: D
53) Which conclusion can be drawn from this evolutionary tree? A) Gradualistic speciation and speciation involving punctuated equilibrium are mutually exclusive concepts; only one of them can occur. B) Eldredge and Gould would deny that the lineages labeled X, Y, and Z could represent true species. C) Assuming that the tip of each line represents a species, there are five extant (i.e., not extinct) species resulting from the earliest common ancestor. D) A single clade (i.e., a group of species that share a common ancestor) can exhibit both gradualism and punctuated equilibrium. E) V and W shared a common ancestor more recently than any of the other species.
Answer: D
53) Which of the following terms are appropriately applied to the situation described in the previous question? A) Sexual selection B) Mate choice C) Intersexual selection D) All three of these E) Only B and C
Answer: D
54) A strong covalent bond between amino acids that functions in maintaining a polypeptideʹs specific three-dimensional shape is a (an) A) ionic bond. B) hydrophobic interaction. C) van der Waals interaction. D) disulfide bond. E) hydrogen bond.
Answer: D
54) In order for chromosomes to undergo inversion or translocation, which of the following is required? A) Point mutation B) Immunological insufficiency C) Advanced maternal age D) Chromosome breakage and rejoining E) Meiosis
Answer: D
54) When hydrogen ions are pumped from the mitochondrial matrix across the inner membrane and into the intermembrane space, the result is the A) formation of ATP. B) reduction of NAD+ . C) restoration of the Na+ /K+ balance across the membrane. D) creation of a proton gradient. E) lowering of pH in the mitochondrial matrix.
Answer: D
54) Which of the following is a function of a signal peptide? A) to direct an mRNA molecule into the cisternal space of the ER B) to bind RNA polymerase to DNA and initiate transcription C) to terminate translation of the messenger RNA D) to translocate polypeptides across the ER membrane E) to signal the initiation of transcription
Answer: D
55) Cells require which of the following to form cilia or flagella? A) centrosomes B) ribosomes C) actin D) A and B only E) A, B, and C
Answer: D
55) Most genes have many more than two alleles. However, which of the following is also true? A) At least one allele for a gene always produces a dominant phenotype. B) Most of the alleles will never be found in a live-born organism. C) All of the alleles but one will produce harmful effects if homozygous. D) There may still be only two phenotypes for the trait. E) More than two alleles in a genotype is lethal.
Answer: D
55) Where is ATP synthase located in the mitochondrion? A) cytosol B) electron transport chain C) outer membrane D) inner membrane E) mitochondrial matrix
Answer: D
55) Which best describes the reaction? A) The amount of free energy initially present in the reactants is indicated by ʺa.ʺ B) The amount of free energy present in the products is indicated by ʺe.ʺ C) The amount of free energy released as a result of the noncatalyzed reaction is indicated by ʺc.ʺ D) The amount of free energy released as a result of the catalyzed reaction is indicated by ʺd.ʺ E) The difference between ʺbʺ and ʺcʺ is the activation energy added by the presence of the enzyme.
Answer: D
56) A hypothetical mutation in a squirrel population produces organisms with eight legs rather than four. Further, these mutant squirrels survive, successfully invade new habitats, and eventually give rise to a new species. The initial event, giving rise to extra legs, would be a good example of A) punctuated equilibrium. B) species selection. C) habitat selection. D) changes in homeotic genes. E) allometry.
Answer: D
56) Assume that the reaction has a △G of -5.6 kcal/mol. Which of the following would be true? A) The reaction could be coupled to power an endergonic reaction with a △G of +6.2 kcal/mol. B) The reaction could be coupled to power an exergonic reaction with a △G of +8.8 kcal/mol. C) The reaction would result in a decrease in entropy ( S) and an increase in the total energy content (H) of the system. D) The reaction would result in an increase in entropy ( S) and a decrease in the total energy content (H) of the system. E) The reaction would result in products (C + D) with a greater free -energy content than in the initial reactants (A + B).
Answer: D
57) A gene is considered to be non-Mendelian in its inheritance pattern if it seems to ʺviolateʺ Mendelʹs laws. Which of the following would then NOT be considered non -Mendelian? A) A gene whose expression varies depending on the gender of the transmitting parent B) A gene derived solely from maternal inheritance C) A gene transmitted via the cytoplasm or cytoplasmic structures D) A gene transmitted to males from the maternal line and from fathers to daughters E) A gene transmitted by a virus to egg-producing cells
Answer: D
57) The loss of ventral spines by modern freshwater sticklebacks is due to natural selection operating on the phenotypic affects of Pitx1 gene A) duplication (gain in number). B) elimination (loss). C) mutation (change). D) silencing (loss of expression). E) up-regulation (increase in expression).
Answer: D
66) Density-dependent inhibition is explained by which of the following? A) As cells become more numerous, they begin to squeeze against each other, restricting their size and ability to produce control factors. B) As cells become more numerous, the cell surface proteins of one cell contact the adjoining cells and they stop dividing. C) As cells become more numerous, the protein kinases they produce begin to compete with each other, such that the proteins produced by one cell essentially cancel those produced by its neighbor. D) As cells become more numerous, more and more of them enter the S phase of the cell cycle. E) As cells become more numerous, the level of waste products increases, eventually slowing down metabolism.
Answer: B
66) Which of the following statements about the 5ʹ end of a polynucleotide strand of DNA is correct? A) The 5ʹ end has a hydroxyl group attached to the number 5 carbon of ribose. B) The 5ʹ end has a phosphate group attached to the number 5 carbon of ribose. C) The 5ʹ end has thymine attached to the number 5 carbon of ribose. D) The 5ʹ end has a carboxyl group attached to the number 5 carbon of ribose. E) The 5ʹ end is the fifth position on one of the nitrogenous bases.
Answer: B
66) Which of the following types of mutation, resulting in an error in the mRNA just after the AUG start of translation, is likely to have the most serious effect on the polypeptide product? A) a deletion of a codon B) a deletion of 2 nucleotides C) a substitution of the third nucleotide in an ACC codon D) a substitution of the first nucleotide of a GGG codon E) an insertion of a codon
Answer: B
66) White blood cells engulf bacteria through what process? A) exocytosis B) phagocytosis C) pinocytosis D) osmosis E) receptor-mediated exocytosis
Answer: B
67) Of the following functions, the major purpose of RNA is to A) transmit genetic information to offspring. B) function in the synthesis of protein. C) make a copy of itself, thus ensuring genetic continuity. D) act as a pattern or blueprint to form DNA. E) form the genes of higher organisms.
Answer: B
69) Which of the following most accurately describes what is happening along this chain? A) Chemiosmosis is coupled with electron transfer. B) Each electron carrier alternates between being reduced and being oxidized. C) ATP is generated at each step. D) Energy of the electrons increases at each step. E) Molecules in the chain give up some of their potential energy.
Answer: B
7) Enzymes that break down DNA catalyze the hydrolysis of the covalent bonds that join nucleotides together. What would happen to DNA molecules treated with these enzymes? A) The two strands of the double helix would separate. B) The phosphodiester linkages between deoxyribose sugars would be broken. C) The purines would be separated from the deoxyribose sugars. D) The pyrimidines would be separated from the deoxyribose sugars. E) All bases would be separated from the deoxyribose sugars.
Answer: B
7) Using RNA as a template for protein synthesis instead of translating proteins directly from the DNA is advantageous for the cell because A) RNA is much more stable than DNA. B) RNA acts as an expendable copy of the genetic material. C) only one mRNA molecule can be transcribed from a single gene, lowering the potential rate of gene expression. D) tRNA, rRNA and others are not transcribed. E) mRNA molecules are subject to mutation but DNA is not.
Answer: B
7) What coefficients must be placed in the following blanks so that all atoms are accounted for in the products? C6H12O6 → ___ C 2H6O + ___ CO2 A) 1; 2 B) 2; 2 C) 1; 3 D) 1; 1 E) 3; 1
Answer: B
7) What is proteomics? A) the linkage of each gene to a particular protein B) the study of the full protein set encoded by a genome C) the totality of the functional possibilities of a single protein D) the study of how amino acids are ordered in a protein E) the study of how a single gene activates many proteins
Answer: B
7) When oxygen is released as a result of photosynthesis, it is a by -product of which of the following? A) reducing NADP+ B) splitting the water molecules C) chemiosmosis D) the electron transfer system of photosystem I E) the electron transfer system of photosystem II
Answer: B
7) When this is taken up by the cell, it binds to the repressor so that the repressor no longer binds to the operator: A) operon B) inducer C) promoter D) repressor E) corepressor
Answer: B
7) Which of the following takes place as an ice cube cools a drink? A) Molecular collisions in the drink increase. B) Kinetic energy in the drink decreases. C) A calorie of heat energy is transferred from the ice to the water of the drink. D) The specific heat of the water in the drink decreases. E) Evaporation of the water in the drink increases.
Answer: B
7) Which of these is the smallest unit that natural selection can change? A) a speciesʹ gene frequency B) a populationʹs gene frequency C) an individualʹs genome D) an individualʹs genotype E) an individualʹs phenotype
Answer: B
70) If one organ is an exaptation of another organ, then what must be true of these two organs? A) They are both vestigial organs. B) They are homologous organs. C) They are undergoing convergent evolution. D) They are found together in the same hybrid species. E) They have the same function.
Answer: B
70) The research team established similar lymphocyte cultures from a number of human donors, including healthy teenagers of both genders, patients already suffering from long- term bacterial infections, and elderly volunteers. They found that the increase in lymphocyte incorporation after pathogen introduction was slightly lower in some of the women teenagers and significantly lower in each of the elderly persons. They repeated the study with a larger number of samples but got the same results. What might be among their conclusions? A) The young women showed these results because they have poorer nutrition. B) The elderly personsʹ samples demonstrated their lowered immune responses. C) The young men had higher response because they are generally healthier. D) The patient samples should have had the lowest response but did not, so the experiment is invalid. E) The elderly donor samples represent cells no longer capable of any cell division.
Answer: B
71) Besides turning enzymes on or off, what other means does a cell use to control enzymatic activity? A) cessation of all enzyme formation B) compartmentalization of enzymes into defined organelles C) exporting enzymes out of the cell D) connecting enzymes into large aggregates E) hydrophobic interactions
Answer: B
71) Heterozygote advantage should be most closely linked to which of the following? A) sexual selection B) stabilizing selection C) random selection D) directional selection E) disruptive selection
Answer: B
71) If a Drosophila female has a homozygous mutation for a maternal effect gene, A) she will not develop past the early embryonic stage. B) all of her offspring will show the mutant phenotype, regardless of their genotype. C) only her male offspring will show the mutant phenotype. D) her offspring will show the mutant phenotype only if they are also homozygous for the mutation. E) only her female offspring will show the mutant phenotype.
Answer: B
71) One of two major forms of a human condition called neurofibromatosis (NF 1) is inherited as a dominant, although it may be either mildly to very severely expressed. If a young child is the first in her family to be diagnosed, which of the following is the best explanation? A) The mother carries the gene but does not express it at all. B) One of the parents has very mild expression of the gene. C) The condition skipped a generation in the family. D) The child has a different allele of the gene than the parents.
Answer: B
71) Which of the following are nitrogenous bases of the purine type? A) cytosine and guanine B) guanine and adenine C) adenine and thymine D) thymine and uracil E) uracil and cytosine
Answer: B
72) In seedcracker finches from Cameroon, small - and large-billed birds specialize in cracking soft and hard seeds, respectively. If long- term climatic change resulted in all seeds becoming hard, what type of selection would then operate on the finch population? A) disruptive selection B) directional selection C) stabilizing selection D) sexual selection E) No selection would operate because the population is in Hardy -Weinberg equilibrium.
Answer: B
73) What is true of the trait whose frequency distribution in a large population appears above? It has probably undergone A) directional selection. B) stabilizing selection. C) disruptive selection. D) sexual selection. E) random selection.
Answer: B
73) Which of the following describes any reaction that has reached chemical equilibrium? A) The concentration of the reactants equals the concentration of the products. B) The rate of the forward reaction is equal to the rate of the reverse reaction. C) All of the reactants have been converted to the products of the reaction. D) All of the products have been converted to the reactants of the reaction. E) Both the forward and the reverse reactions have stopped with no net effect on the concentration of the reactants and the products.
Answer: B
73) Which of the following describes ubiquinone? A) a protein in the electron transport chain B) a small hydrophobic coenzyme C) a substrate for synthesis of FADH D) a vitamin needed for efficient glycolysis E) an essential amino acid
Answer: B
73) Which point mutation would be most likely to have a catastrophic effect on the functioning of a protein? A) a base substitution B) a base deletion near the start of a gene C) a base deletion near the end of the coding sequence, but not in the terminator codon D) deletion of three bases near the start of the coding sequence, but not in the initiator codon E) a base insertion near the end of the coding sequence, but not in the terminator codon
Answer: B
74) Fossil evidence indicates that several kinds of flightless dinosaurs possessed feathers. If some of these feather-bearing dinosaurs incubated clutches of eggs in carefully constructed nests, this might be evidence supporting the claim that A) dinosaurs were as fully endothermal (warm-blooded) as modern birds and mammals. B) their feathers originally served as insulation, and only later became flight surfaces. C) the earliest reptiles could fly, and the feathers of flightless dinosaurs were vestigial flight surfaces. D) the feathers were plucked from the bodies of other adults to provide nest -building materials. E) all fossils with feathers are actually some kind of bird.
Answer: B
74) These genes map out the basic subdivisions along the anterior -posterior axis of the Drosophila embryo: A) homeotic genes B) segmentation genes C) egg-polarity genes D) morphogens E) inducers
Answer: B
74) Which of the following statements are true about protein synthesis in prokaryotes? A) Extensive RNA processing is required before prokaryotic transcripts can be translated. B) Translation can begin while transcription is still in progress. C) Prokaryotic cells have complicated mechanisms for targeting proteins to the appropriate cellular organelles. D) Translation requires antibiotic activity. E) Unlike eukaryotes, prokaryotes require no initiation or elongation factors.
Answer: B
77) If one strand of a DNA molecule has the sequence of bases 5ʹATTGCA3ʹ, the other complementary strand would have the sequence A) 5ʹTAACGT3ʹ. B) 3ʹTAACGT5ʹ. C) 5ʹUAACGU3ʹ. D) 3ʹUAACGU5ʹ. E) 5ʹUGCAAU3ʹ.
Answer: B
77) Pax-6 usually causes the production of a type of light -receptor pigments. In vertebrate eyes, though, a different gene (the rh gene family) is responsible for the light-receptor pigments of the retina. The rh gene, like Pax-6 , is ancient. In the marine ragworm, for example, the rh gene causes production of c -opsin, which helps regulate the wormʹs biological clock. Which of these most likely accounts for vertebrate vision? A) The Pax-6 gene mutated to become the rh gene among early mammals. B) During vertebrate evolution, the rh gene for biological clock opsin was co-opted as a gene for visual receptor pigments. C) In animals more ancient than ragworms, the rh gene(s) coded for visual receptor pigments; in lineages more recent than ragworms, rh has flip- flopped several times between producing biological clock opsins and visual receptor pigments. D) Pax-6 was lost from the mammalian genome, and replaced by the rh gene much later.
Answer: B
77) The product of the bicoid gene in Drosophila could be considered a(n) A) tissue-specific protein. B) cytoplasmic determinant. C) maternal effect. D) inductive signal. E) fertilization product.
Answer: B
77) The same gene that causes various coat patterns in wild and domesticated cats also causes the cross-eyed condition in these cats, the cross-eyed condition being slightly maladaptive. In a hypothetical environment, the coat pattern that is associated with crossed eyes is highly adaptive, with the result that both the coat pattern and the cross -eyed condition increase in a feline population over time. Which statement is supported by these observations? A) Evolution is progressive and tends toward a more perfect population. B) Phenotype is often the result of compromise. C) Natural selection reduces the frequency of maladaptive genes in populations over the course of time. D) Polygenic inheritance is generally maladaptive, and should become less common in future generations. E) In all environments, coat pattern is a more important survival factor than is eye-muscle tone.
Answer: B
78) What is the structural feature that allows DNA to replicate? A) sugar-phosphate backbone B) complementary pairing of the nitrogenous bases C) disulfide bonding (bridging) of the two helixes D) twisting of the molecule to form an α helix E) three-component structure of the nucleotides
Answer: B
79) A new organism is discovered in the forests of Costa Rica. Scientists there determine that the polypeptide sequence of hemoglobin from the new organism has 72 amino acid differences from humans, 65 differences from a gibbon, 49 differences from a rat, and 5 differences from a frog. These data suggest that the new organism A) is more closely related to humans than to frogs. B) is more closely related to frogs than to humans. C) may have evolved from gibbons but not rats. D) is more closely related to humans than to rats. E) may have evolved from rats but not from humans and gibbons.
Answer: B
8) Given Baltimoreʹs scheme, a positive sense single -stranded RNA virus such as the polio virus would be most closely related to which of the following? A) T-series bacteriophages B) retroviruses that require a DNA intermediate C) single-stranded DNA viruses such as herpesviruses D) nonenveloped double-stranded RNA viruses E) linear double-stranded DNA viruses such as adenovirus
Answer: B
8) Two characters that appear in a 9:3:3:1 ratio in the F 2 generation should have which of the following properties? A) Each of the traits is controlled by single genes. B) The genes controlling the characters obey the law of independent assortment. C) Each of the genes controlling the characters has two alleles. D) Four genes are involved. E) Sixteen different phenotypes are possible.
Answer: B
8) Which is a defining characteristic that all protobionts had in common? A) the ability to synthesize enzymes B) a surrounding membrane or membrane - like structure C) RNA genes D) a nucleus E) the ability to replicate RNA
Answer: B
8) Which of the following does not occur during mitosis? A) condensation of the chromosomes B) replication of the DNA C) separation of sister chromatids D) spindle formation E) separation of the spindle poles
Answer: B
8) Which of the following is a true distinction between fermentation and cellular respiration? A) Only respiration oxidizes glucose. B) NADH is oxidized by the electron transport chain in respiration only. C) Fermentation, but not respiration, is an example of a catabolic pathway. D) Substrate- level phosphorylation is unique to fermentation. E) NAD+ functions as an oxidizing agent only in respiration.
Answer: B
8) Which of the following statements correctly describes any chemical reaction that has reached equilibrium? A) The concentrations of products and reactants are equal. B) The rate of the forward reaction equals the rate of the reverse reaction. C) Both forward and reverse reactions have halted. D) The reaction is now irreversible. E) No reactants remain.
Answer: B
83) Why is glycolysis considered to be one of the first metabolic pathways to have evolved? A) It produces much less ATP than does oxidative phosphorylation. B) It is found in the cytosol, does not involve oxygen, and is present in most organisms. C) It is found in prokaryotic cells but not in eukaryotic cells. D) It relies on chemiosmosis which is a metabolic mechanism present only in the first cells-prokaryotic cells. E) It requires the presence of membrane-enclosed cell organelles found only in eukaryotic cells.
Answer: B
85) When muscle cells are oxygen deprived, the heart still pumps. What must the heart cells be able to do? A) derive sufficient energy from fermentation B) continue aerobic metabolism when skeletal muscle cannot C) transform lactate to pyruvate again D) remove lactate from the blood E) remove oxygen from lactate
Answer: B
85) Which molecule has hydrophilic and hydrophobic properties and would be found in plasma membranes? A) 1 B) 5 C) 6 D) 12 E) 14
Answer: B
9) Darwin analogized the effects of evolution as the above -ground portion of a many-branched tree, with extant species being the tips of the twigs. The common ancestor of two species is most analogous to which anatomical tree part? A) a single twig that gets longer with time B) a node where two twigs diverge C) a twig that branches with time D) the trunk E) neighboring twigs attached to the same stem
Answer: B
9) Most CO2 from catabolism is released during A) glycolysis. B) the citric acid cycle. C) lactate fermentation. D) electron transport. E) oxidative phosphorylation.
Answer: B
9) Who would have proposed that the boundaries between each stratum mark the occurrence of different localized floods? A) Lyell B) Cuvier C) Hutton D) Darwin E) Lamarck
Answer: B
9) Within a cell, the amount of protein made using a given mRNA molecule depends partly on A) the degree of DNA methylation. B) the rate at which the mRNA is degraded. C) the presence of certain transcription factors. D) the number of introns present in the mRNA. E) the types of ribosomes present in the cytoplasm.
Answer: B
94) A fat (or triacylglycerol) would be formed as a result of a dehydration reaction between A) one molecule of 9 and three molecules of 10. B) three molecules of 9 and one molecule of 10. C) one molecule of 5 and three molecules of 9. D) three molecules of 5 and one molecule of 9. E) one molecule of 5 and three molecules of 10.
Answer: B
A) have identical three-dimensional shapes. B) are mirror images of one another. C) lack an asymmetric carbon. D) differ in the location of their double bonds. E) differ in their electrical charge.
Answer: B
A) the relative solubility of the component. B) the size and weight of the component. C) the percentage of carbohydrates in the component. D) the number of enzymes in the fraction. E) the presence or absence of lipids in the component.
Answer: B
F) Both illustrations in each of the other answer choices depict enantiomers of the same molecule.
Answer: B
67) In certain motile prokaryotes, dozens of different proteins comprise the motor that powers the prokaryotic flagellum. The motor has a complicated structure, and its various proteins interact to carry out its function. Based on Darwinʹs explanation for the existence of human eyes, how would he probably have explained the existence of such motors? A) Because he could not have explained their existence, he would have used supernatural agents as a temporary explanation until the gap in scientific knowledge had been filled. B) Because he could not have explained their existence, he would have concluded that the human brain has not (and probably cannot) evolve the capability to solve such complex problems. C) He would have proposed that these motors were the products of aliens, and had been delivered to Earth by extraterrestrial visitors. D) He would have proposed that less complicated, but still functional, versions (maybe even with a different function) had existed in ancestral prokaryotes.
Answer: D
58) Genomic imprinting is generally due to the addition of methyl ( -CH3) groups to C nucleotides in order to silence a given gene. If this depends on the sex of the parent who transmits the gene, which of the following must be true? A) Methylation of C is permanent in a gene. B) Genes required for early development stages must not be imprinted. C) Methylation of this kind must occur more in males than in females. D) Methylation must be reversible in ovarian and testicular cells. E) The imprints are transmitted only to gamete -producing cells.
Answer: D
58) Natural selection and recombination due to crossing over during meiosis I are related in which of the following ways? A) Recombinants are usually selected against. B) Non-recombinant organisms are usually favored by natural selection if there is environmental change. C) Most recombinants reproduce less frequently than do non -recombinants. D) Recombinants may have combinations of traits that are favored by natural selection. E) Recombination does not affect natural selection.
Answer: D
58) The cell walls of bacteria, fungi, and plant cells and the extracellular matrix of animal cells are all external to the plasma membrane. Which of the following is a characteristic of all of these extracellular structures? A) They must block water and small molecules in order to regulate the exchange of matter and energy with their environment. B) They must permit information transfer between the cellʹs cytoplasm and the nucleus. C) They must provide a rigid structure that maintains an appropriate ratio of cell surface area to volume. D) They are constructed of materials that are largely synthesized in the cytoplasm and then transported out of the cell. E) They are composed of a mixture of lipids and carbohydrates.
Answer: D
68) Each of the following options is a modification of the sentence THECATATETHERAT. Which of the following is analogous to a frameshift mutation? A) THERATATETHECAT B) THETACATETHERAT C) THECATARETHERAT D) THECATATTHERAT E) CATATETHERAT
Answer: D
11) A space probe discovers a planet inhabited by creatures that reproduce with the same hereditary patterns seen in humans. Three phenotypic characters are height ( T = tall, t = dwarf), head appendages ( A = antennae, a = no antennae), and nose morphology (S = upturned snout, s = downturned snout). Since the creatures are not "intelligent," Earth scientists are able to do some controlled breeding experiments, using various heterozygotes in testcrosses. For tall heterozygotes with antennae, the offspring are: tall -antennae, 46; dwarf-antennae, 7; dwarf-no antennae, 42; tall-no antennae, 5. For heterozygotes with antennae and an upturned snout, the offspring are: antennae -upturned snout, 47; antennae-downturned snout, 2; no antennae -downturned snout, 48; no antennae-upturned snout, 3. Calculate the recombination frequencies for both experiments.
Answer: Between T and A, 12%; between A and S, 5%
1) Bioinformatics includes all of the following except A) using computer programs to align DNA sequences. B) analyzing protein interactions in a species. C) using molecular biology to provide biological information to a system so that it gets expressed. D) development of computer-based tools for genome analysis. E) use of mathematical tools to make sense of biological systems.
Answer: C
1) In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by A) hydrogen bonds. B) nonpolar covalent bonds. C) polar covalent bonds. D) ionic bonds. E) van der Waals interactions.
Answer: C
1) In his work with pneumonia-causing bacteria and mice, Griffith found that A) the protein coat from pathogenic cells was able to transform nonpathogenic cells. B) heat-killed pathogenic cells caused pneumonia. C) some substance from pathogenic cells was transferred to nonpathogenic cells, making them pathogenic. D) the polysaccharide coat of bacteria caused pneumonia. E) bacteriophages injected DNA into bacteria.
Answer: C
1) Organic chemistry is a science based on the study of A) functional groups. B) vital forces interacting with matter. C) carbon compounds. D) water and its interaction with other kinds of molecules. E) inorganic compounds.
Answer: C
1) Phosphorylation cascades involving a series of protein kinases are useful for cellular signal transduction because A) they are species specific. B) they always lead to the same cellular response. C) they amplify the original signal manyfold. D) they counter the harmful effects of phosphatases. E) the number of molecules used is small and fixed.
Answer: C
1) The legless condition that is observed in several groups of extant reptiles is the result of A) their common ancestor having been legless. B) a shared adaptation to an arboreal (living in trees) lifestyle. C) several instances of the legless condition arising independently of each other. D) individual lizards adapting to a fossorial (living in burrows) lifestyle during their lifetimes.
Answer: C
1) When biologists wish to study the internal ultrastructure of cells, they most likely would use A) a light microscope. B) a scanning electron microscope. C) a transmission electronic microscope. D) A and B E) B and C
Answer: C
1) Which enzyme was used to produce the molecule in Figure 20.1? A) ligase B) transcriptase C) a restriction enzyme D) RNA polymerase E) DNA polymerase
Answer: C
1) Which of the following statements about species, as defined by the biological species concept, is (are) correct? I. Biological species are defined by reproductive isolation. II. Biological species are the model used for grouping extinct forms of life. III. The biological species is the largest unit of population in which successful reproduction is possible. A) I only B) II only C) I and III D) II and III E) I, II, and III
Answer: C
1) Which statement correctly characterizes bound ribosomes? A) Bound ribosomes are enclosed in their own membrane. B) Bound and free ribosomes are structurally different. C) Bound ribosomes generally synthesize membrane proteins and secretory proteins. D) The most common location for bound ribosomes is the cytoplasmic surface of the plasma membrane. E) All of the above.
Answer: C
10) A principal problem with inserting an unmodified mammalian gene into a bacterial plasmid, and then getting that gene expressed in bacteria, is that A) prokaryotes use a different genetic code from that of eukaryotes. B) bacteria translate polycistronic messages only. C) bacteria cannot remove eukaryotic introns. D) bacterial RNA polymerase cannot make RNA complementary to mammalian DNA. E) bacterial DNA is not found in a membrane-bounded nucleus and is therefore incompatible with mammalian DNA.
Answer: C
10) Each of the following has a better chance of influencing gene frequencies in small populations than in large populations, but which one most consistently requires a small population as a precondition for its occurrence? A) Mutation B) Non-random mating C) Genetic drift D) Natural selection E) Gene flow
Answer: C
10) One species lives only in tree holes; another species lives only in streams. A) behavioral B) gametic C) habitat D) temporal E) mechanical
Answer: C
10) The first genes on Earth were probably A) DNA produced by reverse transcriptase from abiotically produced RNA. B) DNA molecules whose information was transcribed to RNA and later translated in polypeptides. C) auto-catalytic RNA molecules. D) RNA produced by autocatalytic, proteinaceous enzymes. E) oligopeptides located within protobionts.
Answer: C
10) Waterʹs high specific heat is mainly a consequence of the A) small size of the water molecules. B) high specific heat of oxygen and hydrogen atoms. C) absorption and release of heat when hydrogen bonds break and form. D) fact that water is a poor heat conductor. E) inability of water to dissipate heat into dry air.
Answer: C
10) Which of the following statements best distinguishes hypotheses from theories in science? A) Theories are hypotheses that have been proved. B) Hypotheses are guesses; theories are correct answers. C) Hypotheses usually are relatively narrow in scope; theories have broad explanatory power. D) Hypotheses and theories are essentially the same thing. E) Theories are proved true in all cases; hypotheses are usually falsified by tests.
Answer: C
11) A gene that contains introns can be made shorter (but remain functional) for genetic engineering purposes by using A) RNA polymerase to transcribe the gene. B) a restriction enzyme to cut the gene into shorter pieces. C) reverse transcriptase to reconstruct the gene from its mRNA. D) DNA polymerase to reconstruct the gene from its polypeptide product. E) DNA ligase to put together fragments of the DNA that codes for a particular polypeptide.
Answer: C
11) Which of the following is true of a species that has a chromosome number of 2n = 16? A) The species is diploid with 32 chromosomes per cell. B) The species has 16 sets of chromosomes per cell. C) Each cell has 8 homologous pairs. D) During the S phase of the cell cycle there will be 32 separate chromosomes. E) A gamete from this species has 4 chromosomes.
Answer: C
12) Eukaryotic sexual life cycles show tremendous variation. Of the following elements, which do all sexual life cycles have in common? I. Alternation of generations II. Meiosis III. Fertilization IV. Gametes V. Spores A) I, IV, and V B) I, II, and IV C) II, III, and IV D) II, IV, and V E) All of the above
Answer: C
12) For a repressible operon to be transcribed, which of the following must occur? A) A corepressor must be present. B) RNA polymerase and the active repressor must be present. C) RNA polymerase must bind to the promoter, and the repressor must be inactive. D) RNA polymerase cannot be present, and the repressor must be inactive. E) RNA polymerase must not occupy the promoter, and the repressor must be inactive.
Answer: C
12) Temperature usually increases when water condenses. Which behavior of water is most directly responsible for this phenomenon? A) the change in density when it condenses to form a liquid or solid B) reactions with other atmospheric compounds C) the release of heat by the formation of hydrogen bonds D) the release of heat by the breaking of hydrogen bonds E) the high surface tension of water
Answer: C
58) Which of the following would be a reasonably efficient technique for confirming the diagnosis of CML? A) searching for the number of telomeric sequences on chromosome 22 B) looking for a Phʹ chromosome in a peripheral blood smear C) enzyme assay for thymine kinase activity D) FISH study to determine the chromosomal location of all chromosome 22 q fragments E) identification of the disease phenotype in review of the patientʹs records
Answer: D
12) The volume enclosed by the plasma membrane of plant cells is often much larger than the corresponding volume in animal cells. The most reasonable explanation for this observation is that A) plant cells are capable of having a much higher surface - to-volume ratio than animal cells. B) plant cells have a much more highly convoluted (folded) plasma membrane than animal cells. C) plant cells contain a large vacuole that reduces the volume of the cytoplasm. D) animal cells are more spherical, while plant cells are elongated. E) the basic functions of plant cells are very different from those of animal cells.
Answer: C
13) Chargaffʹs analysis of the relative base composition of DNA was significant because he was able to show that A) the relative proportion of each of the four bases differs within individuals of a species. B) the human genome is more complex than that of other species. C) the amount of A is always equivalent to T, and C to G. D) the amount of ribose is always equivalent to deoxyribose. E) transformation causes protein to be brought into the cell.
Answer: C
13) G proteins and G-protein- linked receptors A) are found only in animal cells, and only embedded in or located just beneath the cellʹs membrane. B) are found only in bacterial cells, embedded in the cellʹs plasma membrane only. C) are thought to have evolved very early, because of their similar structure and function in a wide variety of modern organisms. D) probably evolved from an adaptation of the citric acid cycle. E) are not widespread in nature and were unimportant in the evolution of eukaryotes.
Answer: C
13) In many ways, the regulation of the genes of a particular group of viruses will be similar to the regulation of the host genes. Therefore, which of the following would you expect of the genes of the bacteriophage? A) regulation via acetylation of histones B) positive control mechanisms rather than negative C) control of more than one gene in an operon D) reliance on transcription activators E) utilization of eukaryotic polymerases
Answer: C
13) The best classification system is that which most closely A) unites organisms that possess similar morphologies. B) conforms to traditional, Linnaean taxonomic practices. C) reflects evolutionary history. D) corroborates the classification scheme in use at the time of Charles Darwin. E) reflects the basic separation of prokaryotes from eukaryotes.
Answer: C
14) Altering patterns of gene expression in prokaryotes would most likely serve the organismʹs survival in which of the following ways? A) organizing gene expression so that genes are expressed in a given order B) allowing each gene to be expressed an equal number of times C) allowing the organism to adjust to changes in environmental conditions D) allowing young organisms to respond differently from more mature organisms E) allowing environmental changes to alter the prokaryoteʹs genome
Answer: C
14) How does a genomic library differ from a cDNA library? A) A genomic library contains only noncoding sequences, whereas a cDNA library contains only coding sequences. B) A genomic library varies, dependent on the cell type used to make it, whereas the content of a cDNA library does not. C) A genomic library can be made using a restriction enzyme and DNA ligase only, whereas a cDNA library requires both of these as well as reverse transcriptase and DNA polymerase. D) The genomic library can be replicated but not transcribed. E) The genomic library contains only the genes that can be expressed in the cell.
Answer: C
14) If humans have 2,900 Mb, a specific member of the lily family has 120,000 Mb, and a yeast has ~13 Mb, why canʹt this data allow us to order their evolutionary significance? A) Size matters less than gene density. B) Size does not compare to gene density. C) Size does not vary with gene complexity. D) Size is mostly due to ʺjunkʺ DNA. E) Size is comparable only within phyla.
Answer: C
14) In animals, meiosis results in gametes, and fertilization results in A) spores. B) gametophytes. C) zygotes. D) sporophytes. E) clones.
Answer: C
14) In order for a protein to be an integral membrane protein it would have to be which of the following? A) hydrophilic B) hydrophobic C) amphipathic D) completely covered with phospholipids E) exposed on only one surface of the membrane
Answer: C
14) Several scientific laboratories across the globe are involved in research concerning the origin of life on Earth. Which of these questions is currently the most problematic and would have the greatest impact on our understanding if we were able to answer it? A) How can amino acids, simple sugars, and nucleotides be synthesized abiotically? B) How can RNA molecules catalyze reactions? C) How did RNA sequences come to carry the code for amino acid sequences? D) How could polymers involving lipids and/or proteins form membranes in aqueous environments? E) How can RNA molecules act as templates for the synthesis of complementary RNA molecules?
Answer: C
14) The mathematical expression for the change in free energy of a system is △G =△H-T△S. Which of the following is (are) correct? A) △S is the change in enthalpy, a measure of randomness. B) △H is the change in entropy, the energy available to do work. C) △G is the change in free energy. D) T is the temperature in degrees Celsius.
Answer: C
15) In Darwinʹs thinking, the more closely related two different organisms are, the A) more similar their habitats are. B) less similar their DNA sequences are. C) more recently they shared a common ancestor. D) less likely they are to have the same genes in common. E) more similar they are in size.
Answer: C
15) Mendel accounted for the observation that traits which had disappeared in the F 1 generation reappeared in the F2 generation by proposing that A) new mutations were frequently generated in the F 2 progeny, ʺreinventingʺ traits that had been lost in the F1 . B) the mechanism controlling the appearance of traits was different between the F 1 and the F2 plants. C) traits can be dominant or recessive, and the recessive traits were obscured by the dominant ones in the F 1 . D) the traits were lost in the F1 due to blending of the parental traits. E) members of the F1 generation had only one allele for each character, but members of the F2 had two alleles for each character.
Answer: C
15) Which of the following is a representation of gene density? A) Humans have 2,900 Mb per genome. B) C. elegans has ~20,000 genes. C) Humans have ~25,000 genes in 2,900 Mb. D) Humans have 27,000 bp in introns. E) Fritillaria has a genome 40 times the size of a human.
Answer: C
15) Which of the following terms describes bacteriophage DNA that has become integrated into the host cell chromosome? A) intemperate bacteriophages B) transposons C) prophages D) T-even phages E) plasmids
Answer: C
15) Which of the following types of cells utilize deoxyribonucleic acid (DNA) as their genetic material but do not have their DNA encased within a nuclear envelope? A) animal B) plant C) archaea D) fungi E) protists
Answer: C
16) In which step is an inorganic phosphate added to the reactant?
Answer: C
16) One difference between carbon -12 ( 12 6 C) and carbon-14 ( 14 6 C) is that carbon-14 has A) two more protons than carbon-12. B) two more electrons than carbon-12. C) two more neutrons than carbon-12. D) A and C only E) B and C only
Answer: C
16) The nuclear lamina is an array of filaments on the inner side of the nuclear membrane. If a method were found that could cause the lamina to fall into disarray, what would you expect to be the most likely consequence? A) the loss of all nuclear function B) the inability of the cell to withstand enzymatic digestion C) a change in the shape of the nucleus D) failure of chromosomes to carry genetic information E) inability of the nucleus to keep out destructive chemicals
Answer: C
16) The two molecules shown in Figure 4.1 are best described as A) optical isomers. B) radioactive isotopes. C) structural isomers. D) nonradioactive isotopes. E) geometric isomers.
Answer: C
16) Which of the following are chemical messengers that pass through the plasma membrane of cells and have receptor molecules in the cytoplasm? A) insulin B) testosterone C) cAMP D) epinephrine
Answer: C
16) Which of the following statements describes the lysogenic cycle of lambda (λ) phage? A) After infection, the viral genes immediately turn the host cell into a lambda-producing factory, and the host cell then lyses. B) Most of the prophage genes are activated by the product of a particular prophage gene. C) The phage genome replicates along with the host genome. D) Certain environmental triggers can cause the phage to exit the host genome, switching from the lytic to the lysogenic. E) The phage DNA is incorporated by crossing over into any nonspecific site on the host cellʹs DNA.
Answer: C
17) If relatively small carbonaceous chondrites from space were a significant source of Earthʹs original amino acids, then which two of these would have been most important in permitting their organic materials to survive impact with Earth? I. Carbonaceous chondrites must contain no D-amino acids. II. Earthʹs early atmosphere must have had little free oxygen. III. The chondrites must have arrived on Earth before 4.2 billion years ago. IV. Earthʹs early atmosphere must have been dense enough to dramatically slow the chondrites before they impacted. V. The chondrites must have impacted land, rather than a large body of water. A) I & II B) II & III C) II & IV D) II & V E) III & IV
Answer: C
17) In which reaction does an intermediate pathway become oxidized?
Answer: C
17) Shown here in Figure 4.2 are the structures of glucose and fructose. These two molecules differ in the A) number of carbon, hydrogen, and oxygen atoms. B) types of carbon, hydrogen, and oxygen atoms. C) arrangement of carbon, hydrogen, and oxygen atoms. D) number of oxygen atoms joined to carbon atoms by double covalent bonds. E) answers A, B, and C
Answer: C
17) Theoretically, the production of sterile mules by interbreeding between female horses and male donkeys should A) result in the extinction of one of the two parental species. B) cause convergent evolution. C) strengthen postzygotic barriers between horses and donkeys. D) weaken the intrinsic reproductive barriers between horses and donkeys. E) eventually result in the formation of a single species from the two parental species.
Answer: C
17) Which of the following is true of integral membrane proteins? A) They lack tertiary structure. B) They are loosely bound to the surface of the bilayer. C) They are usually transmembrane proteins. D) They are not mobile within the bilayer. E) They serve only a structural role in membranes.
Answer: C
18) In order to understand the chemical basis of inheritance, one must understand the molecular structure of DNA. This is an example of the application of __________ to the study of biology. A) evolution B) emergent properties C) reductionism D) the cell theory E) feedback regulation
Answer: C
18) The atomic number of carbon is 6. Carbon -14 is heavier than carbon -12 because the atomic nucleus of carbon-14 contains _____ neutrons. A) 6 B) 7 C) 8 D) 12 E) 14
Answer: C
18) The biological species concept is inadequate for grouping A) plants. B) parasites. C) asexual organisms. D) animals that migrate. E) sympatric populations.
Answer: C
18) What proportion of their sons would be color-blind and of normal height? A) All B) None C) Half D) One out of four E) Three out of four
Answer: C
18) Which of the following is true for both prokaryotic and eukaryotic gene expression? A) After transcription, a 3ʹ poly -A tail and a 5ʹ cap are added to mRNA. B) Translation of mRNA can begin before transcription is complete. C) RNA polymerase binds to the promoter region to begin transcription. D) mRNA is synthesized in the 3ʹ → 5ʹ direction. E) The mRNA transcript is the exact complement of the gene from which it was copied.
Answer: C
18) Which of the following shows the correct changes in thermodynamic properties for a chemical reaction in which amino acids are linked to form a protein? A) +△H, +△S, +△G B) +△H, -△S, -△G C) +△H, -△S, +△G D) -△H, -△S, +△G E) -△H, +△S, +△G
Answer: C
18) Which of the life cycles is typical for plants and some algae? A) I only B) II only C) III only D) I and II E) I and III
Answer: C
19) A researcher lyses a cell that contains nucleic acid molecules and capsomeres of tobacco mosaic virus (TMV). The cell contents are left in a covered test tube overnight. The next day this mixture is sprayed on tobacco plants. Which of the following would be expected to occur? A) The plants would develop some but not all of the symptoms of the TMV infection. B) The plants would develop symptoms typically produced by viroids. C) The plants would develop the typical symptoms of TMV infection. D) The plants would not show any disease symptoms. E) The plants would become infected, but the sap from these plants would be unable to infect other plants.
Answer: C
19) The common ancestors of birds and mammals were very early (stem) reptiles, which almost certainly possessed 3-chambered hearts (2 atria, 1 ventricle). Birds and mammals, however, are alike in having 4 -chambered hearts (2 atria, 2 ventricles). The 4 -chambered hearts of birds and mammals are best described as A) structural homologies. B) vestiges. C) homoplasies. D) the result of shared ancestry. E) molecular homologies.
Answer: C
19) Which type of organelle is primarily involved in the synthesis of oils, phospholipids, and steroids? A) ribosome B) lysosome C) smooth endoplasmic reticulum D) mitochondrion E) contractile vacuole
Answer: C
2) According to Beadle and Tatumʹs hypothesis, how many genes are necessary for this pathway? A) 0 B) 1 C) 2 D) 3 E) It cannot be determined from the pathway.
Answer: C
2) According to the fluid mosaic model of membrane structure, proteins of the membrane are mostly A) spread in a continuous layer over the inner and outer surfaces of the membrane. B) confined to the hydrophobic core of the membrane. C) embedded in a lipid bilayer. D) randomly oriented in the membrane, with no fixed inside -outside polarity. E) free to depart from the fluid membrane and dissolve in the surrounding solution.
Answer: C
2) Assume that you are trying to insert a gene into a plasmid. Someone gives you a preparation of genomic DNA that has been cut with restriction enzyme X. The gene you wish to insert has sites on both ends for cutting by restriction enzyme Y. You have a plasmid with a single site for Y, but not for X. Your strategy should be to A) insert the fragments cut with X directly into the plasmid without cutting the plasmid. B) cut the plasmid with restriction enzyme X and insert the fragments cut with Y into the plasmid. C) cut the DNA again with restriction enzyme Y and insert these fragments into the plasmid cut with the same enzyme. D) cut the plasmid twice with restriction enzyme Y and ligate the two fragments onto the ends of the DNA fragments cut with restriction enzyme X. E) cut the plasmid with enzyme X and then insert the gene into the plasmid.
Answer: C
2) For this pair of items, choose the option that best describes their relationship. (A) The probability of finding chitin in fungal cell walls (B) The probability of finding chitin in arthropod exoskeletons A) Item (A) is greater than item (B). B) Item (A) is less than item (B). C) Item (A) is exactly or very approximately equal to item (B). D) Item (A) may stand in more than one of the above relations to item (B).
Answer: C
2) Most cells cannot harness heat to perform work because A) heat is not a form of energy. B) cells do not have much heat; they are relatively cool. C) temperature is usually uniform throughout a cell. D) heat can never be used to do work. E) heat denatures enzymes.
Answer: C
2) The advantage of light microscopy over electron microscopy is that A) light microscopy provides for higher magnification than electron microscopy. B) light microscopy provides for higher resolving power than electron microscopy. C) light microscopy allows one to view dynamic processes in living cells. D) A and B E) B and C
Answer: C
2) The molecular formula for glucose is C6H12O6 . What would be the molecular formula for a polymer made by linking ten glucose molecules together by dehydration reactions? A) C60H120O60 B) C6H12O6 C) C60H102O51 D) C60H100O50 E) C60H111O51
Answer: C
2) The upper forelimbs of humans and bats have fairly similar skeletal structures, whereas the corresponding bones in whales have very different shapes and proportions. However, genetic data suggest that all three kinds of organisms diverged from a common ancestor at about the same time. Which of the following is the most likely explanation for these data? A) Humans and bats evolved by natural selection, and whales evolved by Lamarckian mechanisms. B) Forelimb evolution was adaptive in people and bats, but not in whales. C) Natural selection in an aquatic environment resulted in significant changes to whale forelimb anatomy. D) Genes mutate faster in whales than in humans or bats. E) Whales are not properly classified as mammals.
Answer: C
2) What is the difference between a monohybrid cross and a dihybrid cross? A) A monohybrid cross involves a single parent, whereas a dihybrid cross involves two parents. B) A monohybrid cross produces a single progeny, whereas a dihybrid cross produces two progeny. C) A dihybrid cross involves organisms that are heterozygous for two characters and a monohybrid only one. D) A monohybrid cross is performed for one generation, whereas a dihybrid cross is performed for two generations. E) A monohybrid cross results in a 9:3:3:1 ratio whereas a dihybrid cross gives a 3:1 ratio.
Answer: C
2) Which of the following is (are) true for anabolic pathways? A) They do not depend on enzymes. B) They are usually highly spontaneous chemical reactions. C) They consume energy to build up polymers from monomers. D) They release energy as they degrade polymers to monomers.
Answer: C
20) A Barr body is normally found in the nucleus of which kind of human cell? A) Unfertilized egg cells only B) Sperm cells only C) Somatic cells of a female only D) Somatic cells of a male only E) Both male and female somatic cells
Answer: C
20) Mendelʹs second law of independent assortment has its basis in which of the following events of meiosis I? A) Synapsis of homologous chromosomes B) Crossing over C) Alignment of tetrads at the equator D) Separation of homologs at anaphase E) Separation of cells at telophase
Answer: C
20) When an ionic compound such as sodium chloride (NaCl) is placed in water the component atoms of the NaCl crystal dissociate into individual sodium ions (Na + ) and chloride ions (Cl- ). In contrast, the atoms of covalently bonded molecules (e.g., glucose, sucrose, glycerol) do not generally dissociate when placed in aqueous solution. Which of the following solutions would be expected to contain the greatest number of particles (molecules or ions)? A) 1 L of 0.5 M NaCl B) 1 L of 0.5 M glucose C) 1 L of 1.0 M NaCl D) 1 L of 1.0 M glucose E) C and D will contain equal numbers of particles.
Answer: C
21) Alu elements account for about 10% of the human genome. What does this mean? A) Alu elements cannot be transcribed into RNA. B) Alu elements evolved in very ancient times, before mammalian radiation. C) Alu elements represent the result of transposition. D) No Alu elements are found within individual genes. E) Alu elements are cDNA and therefore related to retrotransposons.
Answer: C
21) During glycolysis, when glucose is catabolized to pyruvate, most of the energy of glucose is A) transferred to ADP, forming ATP. B) transferred directly to ATP. C) retained in the pyruvate. D) stored in the NADH produced. E) used to phosphorylate fructose to form fructose-6-phosphate.
Answer: C
21) Humans can digest starch but not cellulose because A) the monomer of starch is glucose, while the monomer of cellulose is galactose. B) humans have enzymes that can hydrolyze the beta (β) glycosidic linkages of starch but not the alpha (α) glycosidic linkages of cellulose. C) humans have enzymes that can hydrolyze the alpha (α) glycosidic linkages of starch but not the beta (β) glycosidic linkages of cellulose. D) humans harbor starch-digesting bacteria in the digestive tract. E) the monomer of starch is glucose, while the monomer of cellulose is maltose.
Answer: C
21) When blood glucose level rises, the pancreas secretes insulin, and as a result blood glucose level declines. When blood glucose level is low, the pancreas secretes glucagon, and as a result blood glucose level rises. Such regulation of blood glucose level is the result of A) catalytic feedback. B) positive feedback. C) negative feedback. D) bioinformatic regulation. E) protein-protein interactions.
Answer: C
22) As a research scientist, you measure the amount of ATP and NADPH consumed by the Calvin cycle in 1 hour. You find 30,000 molecules of ATP consumed, but only 20,000 molecules of NADPH. Where did the extra ATP molecules come from? A) photosystem II B) photosystem I C) cyclic electron flow D) linear electron flow E) chlorophyll
Answer: C
22) If you were to observe the activity of methylated DNA, you would expect it to A) be replicating nearly continuously. B) be unwinding in preparation for protein synthesis. C) have turned off or slowed down the process of transcription. D) be very actively transcribed and translated. E) induce protein synthesis by not allowing repressors to bind to it.
Answer: C
22) In addition to ATP, what are the end products of glycolysis? A) CO2 and H 2O B) CO2 and pyruvate C) NADH and pyruvate D) CO2 and NADH E) H2O, FADH2 , and citrate
Answer: C
22) Life is diverse. How many species are estimated to be presently on the earth? A) 1,800 B) 180,000 C) 1,800,000 D) 18,000,000 E) 180,000,000
Answer: C
22) The DNA polymerases of all cellular organisms have proofreading capability. This capability tends to reduce the introduction of A) extra genes by gene duplication events. B) chromosomal translocation. C) genetic variation by mutations. D) proofreading capability into prokaryotes.
Answer: C
22) The major advantage of using artificial chromosomes such as YACs and BACs for cloning genes is that A) plasmids are unable to replicate in cells. B) only one copy of a plasmid can be present in any given cell, whereas many copies of a YAC or BAC can coexist in a single cell. C) YACs and BACs can carry much larger DNA fragments than ordinary plasmids can. D) YACs and BACs can be used to express proteins encoded by inserted genes, but plasmids cannot. E) all of the above
Answer: C
22) The two extant species that are most closely related to each other are A) A and B. B) B and C. C) C and D. D) D and E. E) E and A.
Answer: C
22) Which of these are not embedded in the lipid bilayer at all? A) transmembrane proteins B) integral proteins C) peripheral proteins D) integrins E) glycoproteins
Answer: C
23) How many grams of the molecule in Figure 3.2 would be equal to 1 mol of the molecule? (Carbon = 12, Oxygen = 16, Hydrogen = 1) A) 29 B) 30 C) 60 D) 150 E) 342
Answer: C
23) If a particular marine organism is fossilized in the sediments immediately overlying the igneous rock at the arrow labeled ʺII,ʺ at which other location, labeled A—E, would a search be most likely to find more fossils of this organism? A) A B) B C) C D) D E) E
Answer: C
23) Regarding mitosis and cytokinesis, one difference between higher plants and animals is that in plants A) the spindles contain microfibrils in addition to microtubules, whereas animal spindles do not contain microfibrils. B) sister chromatids are identical, but they differ from one another in animals. C) a cell plate begins to form at telophase, whereas in animals a cleavage furrow is initiated at that stage. D) chromosomes become attached to the spindle at prophase, whereas in animals chromosomes do not become attached until anaphase. E) spindle poles contain centrioles, whereas spindle poles in animals do not.
Answer: C
23) The difference in lipid and protein composition between the membranes of the endomembrane system is largely determined by A) the physical separation of most membranes from each other. B) the transportation of membrane among the endomembrane system by small membrane vesicles. C) the function of the Golgi apparatus in sorting membrane components. D) the modification of the membrane components once they reach their final destination. E) the synthesis of lipids and proteins in each of the organelles of the endomembrane system.
Answer: C
23) The free energy for the oxidation of glucose to CO2 and water is -686 kcal/mole and the free energy for the reduction of NAD+ to NADH is +53 kcal/mole. Why are only two molecules of NADH formed during glycolysis when it appears that as many as a dozen could be formed? A) Most of the free energy available from the oxidation of glucose is used in the production of ATP in glycolysis. B) Glycolysis is a very inefficient reaction, with much of the energy of glucose released as heat. C) Most of the free energy available from the oxidation of glucose remains in pyruvate, one of the products of glycolysis. D) There is no CO 2 or water produced as products of glycolysis. E) Glycolysis consists of many enzymatic reactions, each of which extracts some energy from the glucose molecule.
Answer: C
24) If you already knew that the infectious agent was either bacterial or viral, which treatment would allow you to distinguish between these two possibilities? A) I B) II C) III D) IV E) either II or IV
Answer: C
24) In eukaryotes there are several different types of RNA polymerase. Which type is involved in transcription of mRNA for a globin protein? A) ligase B) RNA polymerase I C) RNA polymerase II D) RNA polymerase III E) primase
Answer: C
24) Prokaryotic and eukaryotic cells generally have which of the following features in common? A) a membrane-bounded nucleus B) a cell wall made of cellulose C) ribosomes D) flagella or cilia that contain microtubules E) linear chromosomes made of DNA and protein
Answer: C
24) Two closely related populations of mice have been separated for many generations by a river. Climatic change causes the river to dry up, thereby bringing the mice populations back into contact in a zone of overlap. Which of the following is not a possible outcome when they meet? A) They interbreed freely and produce fertile hybrid offspring. B) They no longer attempt to interbreed. C) They interbreed in the region of overlap, producing an inferior hybrid. Subsequent interbreeding between inferior hybrids produces progressively superior hybrids over several generations. D) They remain separate in the extremes of their ranges but develop a persistent hybrid zone in the area of overlap. E) They interbreed in the region of overlap, but produce sterile offspring.
Answer: C
24) Which is a true statement concerning genetic variation? A) It is created by the direct action of natural selection. B) It arises in response to changes in the environment. C) It must be present in a population before natural selection can act upon the population. D) It tends to be reduced by the processes involved when diploid organisms produce gametes. E) A population that has a higher average heterozygosity has less genetic variation than one with a larger average heterozygosity.
Answer: C
24) Which of the following s eals the sticky ends of restriction fragments to make recombinant DNA? A) restriction enzymes B) gene cloning C) DNA ligase D) gel electrophoresis E) reverse transcriptase
Answer: C
25) A karyotype results from which of the following? A) A natural cellular arrangement of chromosomes in the nucleus B) An inherited ability of chromosomes to arrange themselves C) The ordering of human chromosome images D) The cutting and pasting of parts of chromosomes to form the standard array E) The separation of homologous chromosomes at metaphase I of meiosis
Answer: C
25) Assuming that the rate of sea- floor spreading was constant during the 1 -million-year period depicted above, what should be the approximate age of marine fossils found in undisturbed sedimentary rock immediately overlying the igneous rock at the arrow labeled ʺIIʺ? A) 10,000 years B) 250,000 years C) 500,000 years D) 1,000,000 years
Answer: C
25) Given the parents AABBCc × AabbCc, assume simple dominance and independent assortment. What proportion of the progeny will be expected to phenotypically resemble the first parent? A) 1/4 B) 1/8 C) 3/4 D) 3/8 E) 1
Answer: C
25) Which of the following statements correctly describes some aspect of protein disposal from prokaryotic cells? A) Prokaryotes are unlikely to be able to excrete proteins because they lack an endomembrane system. B) The mechanism of protein excretion in prokaryotes is probably the same as that in eukaryotes. C) Proteins that are excreted by prokaryotes are synthesized on ribosomes that are bound to the cytoplasmic surface of the plasma membrane. D) In prokaryotes, the ribosomes that are used for the synthesis of secreted proteins are located outside of the cell. E) Prokaryotes contain large pores in their plasma membrane that permit the movement of proteins out of the cell.
Answer: C
26) A part of the promoter, called the TATA box, is said to be highly conserved in evolution. Which might this illustrate? A) The sequence evolves very rapidly. B) The sequence does not mutate. C) Any mutation in the sequence is selected against. D) The sequence is found in many but not all promoters. E) The sequence is transcribed at the start of every gene.
Answer: C
26) An Okazaki fragment has which of the following arrangements? A) primase, polymerase, ligase B) 3ʹ RNA nucleotides, DNA nucleotides 5ʹ C) 5ʹ RNA nucleotides, DNA nucleotides 3ʹ D) DNA polymerase I, DNA polymerase III E) 5ʹ DNA to 3ʹ
Answer: C
26) Cell membranes are asymmetrical. Which of the following is a most likely explanation? A) The cell membrane forms a border between one cell and another in tightly packed tissues such as epithelium. B) Cell membranes communicate signals from one organism to another. C) Cell membrane proteins are determined as the membrane is being packaged in the ER and Golgi. D) The ʺinnernessʺ and ʺouternessʺ of membrane surfaces are predetermined by genes. E) Proteins can only span cell membranes if they are hydrophobic.
Answer: C
26) Tay-Sachs disease is a human genetic abnormality that results in cells accumulating and becoming clogged with very large and complex lipids. Which cellular organelle must be involved in this condition? A) the endoplasmic reticulum B) the Golgi apparatus C) the lysosome D) mitochondria E) membrane-bound ribosomes
Answer: C
26) Which of the following is true regarding saturated fatty acids? A) They are the predominant fatty acid in corn oil. B) They have double bonds between carbon atoms of the fatty acids. C) They are the principal molecules in lard and butter. D) They are usually liquid at room temperature. E) They are usually produced by plants.
Answer: C
27) Chromosomes first become visible during which phase of mitosis? A) prometaphase B) telophase C) prophase D) metaphase E) anaphase
Answer: C
27) If this figure is an accurate depiction of relatedness, then which taxon is unacceptable, based on cladistics? A) 1 B) 2 C) 3 D) 4 E) 5
Answer: C
27) What is the estimated frequency of allele A in the gene pool? A) 0.05 B) 0.25 C) 0.50 D) 0.75 E) 1.00
Answer: C
27) What is true of the fossil record of mammalian origins? A) It is a good example of punctuated equilibrium. B) It shows that mammals and birds evolved from the same kind of dinosaur. C) It includes transitional forms with progressively specialized teeth. D) It indicates that mammals and dinosaurs did not overlap in geologic time. E) It includes a series that shows the gradual change of scales into fur.
Answer: C
27) When does exon shuffling occur? A) during splicing of DNA B) during mitotic recombination C) as an alternative splicing pattern in post - transcriptional processing D) as an alternative cleavage or modification post - translationally E) as the result of faulty DNA repair
Answer: C
27) Which kind of metabolic poison would most directly interfere with glycolysis? A) an agent that reacts with oxygen and depletes its concentration in the cell B) an agent that binds to pyruvate and inactivates it C) an agent that closely mimics the structure of glucose but is not metabolized D) an agent that reacts with NADH and oxidizes it to NAD + E) an agent that blocks the passage of electrons along the electron transport chain
Answer: C
27) Which of Darwinʹs ideas had the strongest connection to Darwin having read Malthusʹs essay on human population growth? A) Descent with modification B) Variation among individuals in a population C) Struggle for existence D) The ability of related species to be conceptualized in ʺtree thinkingʺ E) That the ancestors of the Galapagos finches had come from the South American mainland
Answer: C
28) In order to determine the probable function of a particular sequence of DNA in humans, what might be the most reasonable approach? A) Prepare a knockout mouse without a copy of this sequence and examine the mouse phenotype. B) Genetically engineer a mouse with a copy of this sequence and examine its phenotype. C) Look for a reasonably identical sequence in another species, prepare a knockout of this sequence in that species and look for the consequences. D) Prepare a genetically engineered bacterial culture with the sequence inserted and assess which new protein is synthesized. E) Mate two individuals heterozygous for the normal and mutated sequences.
Answer: C
28) Restriction fragments of DNA are typically separated from one another by which process? A) filtering B) centrifugation C) gel electrophoresis D) PCR E) electron microscopy
Answer: C
28) What proportion of the population is probably heterozygous (Aa) for this trait? A) 0.05 B) 0.25 C) 0.50 D) 0.75 E) 1.00
Answer: C
28) Which enzyme catalyzes the elongation of a DNA strand in the 5ʹ → 3ʹ direction? A) primase B) DNA ligase C) DNA polymerase III D) topoisomerase E) helicase
Answer: C
28) Which of the following help(s) to stabilize mRNA by inhibiting its degradation? A) TATA box B) spliceosomes C) 5ʹ cap and poly (A) tail D) introns E) RNA polymerase
Answer: C
28) Which of the following is the best explanation for the inability of an animal cell to reduce the Ca2+ concentration in its cytosol compared with the extracellular fluid? A) blockage of the synaptic signal B) loss of transcription factors C) insufficient ATP levels in the cytoplasm D) low oxygen concentration around the cell E) low levels of protein kinase in the cell
Answer: C
28) Which of the following statements is true regarding the molecule illustrated in Figure 5.3? A) It is a saturated fatty acid. B) A diet rich in this molecule may contribute to atherosclerosis. C) Molecules of this type are usually liquid at room temperature. D) A and B only E) A, B and C
Answer: C
28) Which of these is reflective of the hierarchical organization of life from most to least inclusive? A) kingdom, order, family, phylum, class, genus, species B) phylum, class, order, kingdom, family, genus, species C) kingdom, phylum, class, order, family, genus, species D) genus, species, kingdom, phylum, class, order, family E) class, order, kingdom, phylum, family, genus, species
Answer: C
28) Why are lipids and proteins free to move laterally in membranes? A) The interior of the membrane is filled with liquid water. B) There are no covalent bonds between lipid and protein in the membrane. C) Hydrophilic portions of the lipids are in the interior of the membrane. D) There are only weak hydrophobic interactions in the interior of the membrane. E) Molecules such as cellulose can pull them in various directions.
Answer: C
68) It has been found that certain proteins of the complex motor that drives bacterial flagella are modified versions of proteins that had previously belonged to plasma membrane pumps. This is evidence in support of the claim that A) some structures are so complex that natural selection cannot, and will not, explain their origins. B) the power of natural selection allows it to act in an almost predictive fashion, producing organs that will be needed in future environments. C) the motors of bacterial flagella were originally synthesized abiotically. D) natural selection can produce new structures by cobbling together parts of other structures. E) bacteria that possess flagella must have lost the ability to pump certain chemicals across their plasma membranes.
Answer: D
29) A number of systems for pumping across membranes are powered by ATP. Such ATP-powered pumps are often called ATPases although they donʹt often hydrolyze ATP unless they are simultaneously transporting ions. Small increases in calcium ions in the cytosol trigger a number of different intracellular reactions, so the cells must keep the calcium concentration quite low. Muscle cells also transport calcium from the cytosol into the membranous system called the sarcoplasmic reticulum (SR). If a muscle cell cytosol has a free calcium ion concentration of 10-7 in a resting cell, while the concentration in the SR can be 10-2 , then how is the ATPase acting? A) The ATP must be powering an inflow of calcium from the outside of the cell into the SR. B) ATP must be transferring Pi to the SR to enable this to occur. C) ATPase activity must be pumping calcium from the cytosol to the SR against the concentration gradient. D) The calcium ions must be diffusing back into the SR along the concentration gradient. E) The route of calcium ions must be from SR to the cytosol, to the cellʹs environment.
Answer: C
29) Atoms whose outer electron shells contain eight electrons tend to A) form ionic bonds in aqueous solutions. B) form covalent bonds in aqueous solutions. C) be stable and chemically nonreactive, or inert. D) be unstable and chemically very reactive. E) be isotopes and very radioactive.
Answer: C
29) During DNA replication, A) all methylation of the DNA is lost at the first round of replication. B) DNA polymerase is blocked by methyl groups, and methylated regions of the genome are therefore left uncopied. C) methylation of the DNA is maintained because methylation enzymes act at DNA sites where one strand is already methylated and thus correctly methylates daughter strands after replication. D) methylation of the DNA is maintained because DNA polymerase directly incorporates methylated nucleotides into the new strand opposite any methylated nucleotides in the template. E) methylated DNA is copied in the cytoplasm, and unmethylated DNA in the nucleus.
Answer: C
29) Ultimately, which of these serves as the basis for both the principle of maximum parsimony and the principle that shared complexity indicates homology rather than analogy? A) the laws of thermodynamics B) Boyleʹs law C) the laws of probability D) chaos theory E) Hutchinsonʹs law
Answer: C
29) What determines the nucleotide sequence of the newly synthesized strand during DNA replication? A) the particular DNA polymerase catalyzing the reaction B) the relative amounts of the four nucleoside triphosphates in the cell C) the nucleotide sequence of the template strand D) the primase used in the reaction E) the arrangement of histones in the sugar phosphate backbone
Answer: C
29) What is the mechanism for the production of genetic recombinants? A) X inactivation B) Methylation of cytosine C) Crossing over and independent assortment D) Nondisjunction E) Deletions and duplications during meiosis
Answer: C
3) Males of different species of the fruit fly Drosophila that live in the same parts of the Hawaiian islands have different elaborate courtship rituals that involve fighting other males and stylized movements that attract females. What type of reproductive isolation does this represent? A) habitat isolation B) temporal isolation C) behavioral isolation D) gametic isolation E) postzygotic barriers
Answer: C
3) Plants are more readily manipulated by genetic engineering than are animals because A) plant genes do not contain introns. B) more vectors are available for transferring recombinant DNA into plant cells. C) a somatic plant cell can often give rise to a complete plant. D) genes can be inserted into plant cells by microinjection. E) plant cells have larger nuclei.
Answer: C
3) The various taxonomic levels (viz, genera, classes, etc.) of the hierarchical classification system differ from each other on the basis of A) how widely the organisms assigned to each are distributed throughout the environment. B) the body sizes of the organisms assigned to each. C) their inclusiveness. D) the relative genome sizes of the organisms assigned to each. E) morphological characters that are applicable to all organisms.
Answer: C
7) Bacteria that contain the plasmid, but not the eukaryotic gene, would grow A) in the nutrient broth plus ampicillin, but not in the broth containing tetracycline. B) only in the broth containing both antibiotics. C) in the broth containing tetracycline, but not in the broth containing ampicillin. D) in all four types of broth. E) in the nutrient broth without antibiotics only.
Answer: D
7) Cells do not catabolize carbon dioxide because A) its double bonds are too stable to be broken. B) CO2 has fewer bonding electrons than other organic compounds. C) CO2 is already completely reduced. D) CO2 is already completely oxidized. E) the molecule has too few atoms.
Answer: D
3) Three or four of the following statements are true and correct. Which one, if any, is false? If all the statements are true, choose answer E. A) Carbon, hydrogen, oxygen, and nitrogen make up approximately 96% of living matter. B) The trace element iodine is required only in very small quantities by vertebrates. C) Virtually all organisms require the same elements in the same quantities. D) Iron is an example of an element needed by all organisms. E) All of the other statements are true and correct.
Answer: C
3) Which metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule? A) the citric acid cycle B) the electron transport chain C) glycolysis D) synthesis of acetyl CoA from pyruvate E) reduction of pyruvate to lactate
Answer: C
3) Which of the following characteristics, structures, or processes is common to both bacteria and viruses? A) metabolism B) ribosomes C) genetic material composed of nucleic acid D) cell division E) independent existence
Answer: C
3) Which of the various species concepts distinguishes two species based on the degree of genetic exchange between their gene pools? A) phylogenetic B) ecological C) biological D) morphological
Answer: C
7) How many different combinations of maternal and paternal chromosomes can be packaged in gametes made by an organism with a diploid number of 8 (2 n = 8)? A) 2 B) 4 C) 8 D) 16 E) 32
Answer: D
7) Which chemical group is most likely to be responsible for an organic molecule behaving as a base? A) hydroxyl B) carbonyl C) carboxyl D) amino E) phosphate
Answer: D
30) Eukaryotic telomeres replicate differently than the rest of the chromosome. This is a consequence of which of the following? A) The evolution of telomerase enzyme B) DNA polymerase that cannot replicate the leading strand template to its 5ʹ end C) Gaps left at the 5ʹ end of the lagging strand because of the need for a 3ʹ onto which nucleotides can attach D) Gaps left at the 3ʹ end of the lagging strand because of the need for a primer E) The ʺno endsʺ of a circular chromosome
Answer: C
30) Synthesis of ATP by the chemiosmotic mechanism occurs during A) photosynthesis. B) respiration. C) both photosynthesis and respiration. D) neither photosynthesis nor respiration. E) photorespiration.
Answer: C
30) Which of the five common ancestors, labeled V—Z, has given rise to the greatest number of species, both extant and extinct? A) V B) W C) X D) Y E) Z
Answer: C
30) Why is coenzyme A, a sulfur containing molecule derived from a B vitamin, added? A) because sulfur is needed for the molecule to enter the mitochondrion B) in order to utilize this portion of a B vitamin which would otherwise be a waste product from another pathway C) to provide a relatively unstable molecule whose acetyl portion can readily bind to oxaloacetate D) because it drives the reaction that regenerates NAD + E) in order to remove one molecule of CO2
Answer: C
30) You have a freshly -prepared 1M solution of glucose in water. You carefully pour out a 100 mL sample of that solution. How many glucose molecules are included in that 100 mL sample? A) 6.02 × 1023 B) 3.01 × 1023 C) 6.02 × 1024 D) 12.04 × 1023 E) 6.02 × 1022
Answer: C
31) Which is one of the main energy transformers of cells? A) lysosome B) vacuole C) mitochondrion D) Golgi apparatus E) peroxisome
Answer: C
32) What is the structure shown in Figure 5.4? A) starch molecule B) protein molecule C) steroid molecule D) cellulose molecule E) phospholipid molecule
Answer: C
32) Which of the following contains its own DNA and ribosomes? A) lysosome B) vacuole C) mitochondrion D) Golgi apparatus E) peroxisome
Answer: C
33) A 1:2:1 phenotypic ratio in the F 2 generation of a monohybrid cross is a sign of A) complete dominance. B) multiple alleles. C) incomplete dominance. D) polygenic inheritance. E) pleiotropy.
Answer: C
33) Sucrose is a disaccharide, composed of the monosaccharides glucose and fructose. The hydrolysis of sucrose by the enzyme sucrase results in A) bringing glucose and fructose together to form sucrose. B) the release of water from sucrose as the bond between glucose and fructose is broken. C) breaking the bond between glucose and fructose and forming new bonds from the atoms of water. D) production of water from the sugar as bonds are broken between the glucose monomers. E) utilization of water as a covalent bond is formed between glucose and fructose to form sucrase.
Answer: C
33) Which diagram represents prophase I of meiosis? A) I B) II C) IV D) V E) VI
Answer: C
33) Which of the following statements is correct about diffusion? A) It is very rapid over long distances. B) It requires an expenditure of energy by the cell. C) It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration. D) It is an active process in which molecules move from a region of lower concentration to one of higher concentration. E) It requires integral proteins in the cell membrane.
Answer: C
33) Which two functional groups are always found in amino acids? A) ketone and aldehyde B) carbonyl and carboxyl C) carboxyl and amino D) phosphate and sulfhydryl E) hydroxyl and aldehyde
Answer: C
34) All of the following statements are part of Charles Darwinʹs concept of natural selection except A) Slight inheritable variations within a population may make an individual significantly more or less likely to survive in its environment, and thus to reproduce. B) Every organism has the potential to produce more offspring than the local environment can support. C) Characteristics of organisms are inherited as genes on chromosomes. D) Better adapted members of a species will survive and reproduce more successfully. E) Most individuals in a species do not survive to reproduce.
Answer: C
34) Amino acids are acids because they always possess which functional group? A) amino B) carbonyl C) carboxyl D) sulfhydryl E) aldehyde
Answer: C
34) If there are 4,000 children born to this generation, how many would be expected to have AB blood under the conditions of Hardy-Weinberg equilibrium? A) 100 B) 960 C) 1,920 D) 2,000 E) 2,400
Answer: C
34) What is thought to be the correct sequence of these events, from earliest to most recent, in the evolution of life on Earth? 1. origin of mitochondria 2. origin of multicellular eukaryotes 3. origin of chloroplasts 4. origin of cyanobacteria 5. origin of fungal-plant symbioses A) 4, 3, 2, 1, 5 B) 4, 1, 2, 3, 5 C) 4, 1, 3, 2, 5 D) 4, 3, 1, 5, 2 E) 3, 4, 1, 2, 5
Answer: C
34) Which of the following procedures would produce RFLPs? A) incubating a mixture of single-stranded DNA from two closely related species B) incubating DNA nucleotides with DNA polymerase C) incubating DNA with restriction enzymes D) incubating RNA with DNA nucleotides and reverse transcriptase E) incubating DNA fragments with ʺsticky endsʺ with ligase
Answer: C
35) A solution of starch at room temperature does not readily decompose to form a solution of simple sugars because A) the starch solution has less free energy than the sugar solution. B) the hydrolysis of starch to sugar is endergonic. C) the activation energy barrier for this reaction cannot be surmounted. D) starch cannot be hydrolyzed in the presence of so much water. E) starch hydrolysis is nonspontaneous.
Answer: C
35) Adenylyl cyclase has the opposite effect of which of the following? A) protein kinase B) protein phosphatase C) phosphodiesterase D) phosphorylase E) GTPase
Answer: C
35) Chloride ion channels are membrane structures that include which of the following? A) gap junctions B) aquaporins C) hydrophilic proteins D) carbohydrates E) sodium ions
Answer: C
35) If it were possible to conduct sophisticated microscopic and chemical analyses of microfossils found in 3.2-billion-year-old stromatolites, then within such microfossils, one should be surprised to observe evidence of: I. double-stranded DNA II. a nuclear envelope III. a nucleoid IV. a nucleolus V. nucleic acids A) II only B) III only C) II and IV D) II, III, and IV E) all five of these
Answer: C
35) In a hypothetical environment, fishes called pike -cichlids are visual predators of algae-eating fish (i.e., they locate their prey by sight). If a population of algae -eaters experiences predation pressure from pike -cichlids, which of the following should least likely be observed in the algae -eater population over the course of many generations? A) Selection for drab coloration of the algae -eaters B) Selection for nocturnal algae-eaters (active only at night) C) Selection for larger female algae-eaters, bearing broods composed of more, and larger, young D) Selection for algae-eaters that become sexually mature at smaller overall body sizes E) Selection for algae-eaters that are faster swimmers
Answer: C
35) In order for anaphase to begin, which of the following must occur? A) Chromatids must lose their kinetochores. B) Cohesin must attach the sister chromatids to each other. C) Cohesin must be cleaved enzymatically. D) Kinetochores must attach to the metaphase plate. E) Spindle microtubules must begin to depolymerize.
Answer: C
35) In the narrow hybrid zone that separates the toad species Bombina bombina and Bombina variegata, what is true of those alleles that are unique to the parental species? A) Such alleles should be absent. B) Their allele frequency should be nearly the same as the allele frequencies in toad populations distant from the hybrid zone. C) The allelesʹ heterozygosity should be higher among the hybrid toads there. D) Their allele frequency on one edge of the hybrid zone should roughly equal their frequency on the opposite edge of the hybrid zone.
Answer: C
36) Caffeine is an inhibitor of phosphodiesterase. Therefore, the cells of a person who has recently consumed coffee would have increased levels of A) phosphorylated proteins. B) GTP. C) cAMP. D) adenylyl cyclase. E) activated G proteins.
Answer: C
36) DNA microarrays have made a huge impact on genomic studies because they A) can be used to eliminate the function of any gene in the genome. B) can be used to introduce entire genomes into bacterial cells. C) allow the expression of many or even all of the genes in the genome to be compared at once. D) allow physical maps of the genome to be assembled in a very short time. E) dramatically enhance the efficiency of restriction enzymes.
Answer: C
36) During splicing, which molecular component of the spliceosome catalyzes the excision reaction? A) protein B) DNA C) RNA D) lipid E) sugar
Answer: C
36) If a human interphase nucleus contains three Barr bodies, it can be assumed that the person A) has hemophilia. B) is a male. C) has four X chromosomes. D) has Turner syndrome. E) has Down syndrome.
Answer: C
36) In a protein complex for the light reaction (a reaction center), energy is transferred from pigment molecule to pigment molecule, to a special chlorophyll a molecule, and eventually to the primary electron acceptor. Why does this occur? A) The action spectrum of that molecule is such that it is different from other molecules of chlorophyll. B) The potential energy of the electron has to go back to the ground state. C) The molecular environment lets it boost an electron to a higher energy level and also to transfer the electron to another molecule. D) Each pigment molecule has to be able to act independently to excite electrons. E) These chlorophyll a molecules are associated with higher concentrations of ATP.
Answer: C
36) Recent evidence indicates that the first major diversification of multicellular eukaryotes may have coincided in time with the A) origin of prokaryotes. B) switch to an oxidizing atmosphere. C) melting that ended the ʺsnowball Earthʺ period. D) origin of multicellular organisms. E) massive eruptions of deep-sea vents.
Answer: C
36) There are 20 different amino acids. What makes one amino acid different from another? A) different carboxyl groups attached to an alpha (α) carbon B) different amino groups attached to an alpha (α) carbon C) different side chains (R groups) attached to an alpha (α) carbon D) different alpha (α) carbons E) different asymmetric carbons
Answer: C
36) Which of these reduces gene flow between the gene pools of the two species on Sao Tomé, despite the existence of hybrids? A) hybrid breakdown B) hybrid inviability C) hybrid sterility D) temporal isolation E) a geographic barrier
Answer: C
37) How many molecules of carbon dioxide (CO 2 ) would be produced by five turns of the citric acid cycle? A) 2 B) 5 C) 10 D) 12 E) 60
Answer: C
37) If nondisjunction occurs in meiosis II during gametogenesis, what will be the result at the completion of meiosis? A) All the gametes will be diploid. B) Half of the gametes will be n + 1, and half will be n — 1. C) 1/4 of the gametes will be n + 1, one will be n — 1, and two will be n. D) There will be three extra gametes. E) Two of the four gametes will be haploid, and two will be diploid.
Answer: C
37) What is the function of DNA polymerase III? A) to unwind the DNA helix during replication B) to seal together the broken ends of DNA strands C) to add nucleotides to the end of a growing DNA strand D) to degrade damaged DNA molecules E) to rejoin the two DNA strands (one new and one old) after replication
Answer: C
37) Which functional groups can act as acids? A) amine and sulfhydryl B) carbonyl and carboxyl C) carboxyl and phosphate D) hydroxyl and aldehyde E) ketone and amino
Answer: C
38) How many reduced dinucleotides would be produced with four turns of the citric acid cycle? A) 1 FADH2 and 4 NADH B) 2 FADH2 and 8 NADH C) 4 FADH2 and 12 NADH D) 1 FAD and 4 NAD+ E) 4 FAD+ and 12 NAD+
Answer: C
38) If four of the original colonists died before they produced offspring, the ratios of genotypes could be quite different in the subsequent generations. This would be an example of A) diploidy. B) gene flow. C) genetic drift. D) disruptive selection. E) stabilizing selection.
Answer: C
38) In the structural organization of many eukaryotic genes, individual exons may be related to which of the following? A) the sequence of the intron that immediately precedes each exon B) the number of polypeptides making up the functional protein C) the various domains of the polypeptide product D) the number of restriction enzyme cutting sites E) the number of start sites for transcription
Answer: C
38) Initially, in terms of tonicity, the solution in side A with respect to that in side B is A) hypotonic. B) plasmolyzed. C) isotonic. D) saturated. E) hypertonic.
Answer: C
38) Which describes the transfer of polypeptide sequences to a membrane to analyze gene expression? A) Southern blotting B) Northern blotting C) Western blotting D) Eastern blotting E) RT-PCR
Answer: C
38) Which event is nearest in time to the end of the period known as snowball Earth? A) oxygenation of Earthʹs seas and atmosphere B) evolution of mitochondria C) Cambrian explosion D) evolution of true multicellularity E) Permian extinction
Answer: C
39) A researcher found a method she could use to manipulate and quantify phosphorylation and methylation in embryonic cells in culture. She tried decreasing the amount of methylation enzymes in the embryonic stem cells and then allowed the cells to further differentiate. Which of the following results would she most likely see? A) increased chromatin condensation B) decreased chromatin concentration C) abnormalities of mouse embryos D) decreased binding of transcription factors E) inactivation of the selected genes
Answer: C
39) After the system reaches equilibrium, what changes are observed? A) The molarity of sucrose and glucose are equal on both sides. B) The molarity of glucose is higher in side A than in side B. C) The water level is higher in side A than in side B. D) The water level is unchanged. E) The water level is higher in side B than in side A.
Answer: C
39) If 3TC resistance is costly for HIV, then which plot (I—IV) best represents the response of a strain of 3TC- resistant HIV over time, if 3TC administration begins at the time indicated by the arrow? A) I B) II C) III D) IV
Answer: C
39) Using only the information provided in the paragraph, which of these is the best initial hypothesis for how D. santomea descended from D. yakuba? A) geographic isolation B) autopolyploidy C) habitat differentiation D) sexual selection E) allopolyploidy
Answer: C
4) A localized group of organisms that belong to the same species is called a A) biosystem. B) community. C) population. D) ecosystem. E) family.
Answer: C
4) How is photosynthesis similar in C4 and CAM plants? A) In both cases, only photosystem I is used. B) Both types of plants make sugar without the Calvin cycle. C) In both cases, rubisco is not used to fix carbon initially. D) Both types of plants make most of their sugar in the dark. E) In both cases, thylakoids are not involved in photosynthesis.
Answer: C
4) If A, B, and C are all required for growth, a strain that is mutant for the gene encoding enzyme A would be able to grow on which of the following media? A) minimal medium B) minimal medium supplemented with nutrient ʺAʺ only C) minimal medium supplemented with nutrient ʺBʺ only D) minimal medium supplemented with nutrient ʺCʺ only E) minimal medium supplemented with nutrients ʺAʺ and ʺCʺ
Answer: C
4) If a horticulturist breeding gardenias succeeds in having a single plant with a particularly desirable set of traits, which of the following would be her most probable and efficient route to establishing a line of such plants? A) Backtrack through her previous experiments to obtain another plant with the same traits. B) Breed this plant with another plant with much weaker traits. C) Clone the plant asexually to produce an identical one. D) Force the plant to self-pollinate to obtain an identical one. E) Add nitrogen to the soil of the offspring of this plant so the desired traits continue.
Answer: C
4) In mitochondria, exergonic redox reactions A) are the source of energy driving prokaryotic ATP synthesis. B) are directly coupled to substrate - level phosphorylation. C) provide the energy that establishes the proton gradient. D) reduce carbon atoms to carbon dioxide. E) are coupled via phosphorylated intermediates to endergonic processes.
Answer: C
4) One difference between cancer cells and normal cells is that cancer cells A) are unable to synthesize DNA. B) are arrested at the S phase of the cell cycle. C) continue to divide even when they are tightly packed together. D) cannot function properly because they are affected by density -dependent inhibition. E) are always in the M phase of the cell cycle.
Answer: C
4) Systems biology is mainly an attempt to A) understand the integration of all levels of biological organization from molecules to the biosphere. B) simplify complex problems by reducing the system into smaller, less complex units. C) construct models of the behavior of entire biological systems. D) build high- throughput machines for the rapid acquisition of biological data. E) speed up the technological application of scientific knowledge.
Answer: C
4) The atomic number of sulfur is 16. Sulfur combines with hydrogen by covalent bonding to form a compound, hydrogen sulfide. Based on the number of valence electrons in a sulfur atom, predict the molecular formula of the compound: A) HS B) HS2 C) H2S D) H3S2 E) H4S
Answer: C
4) Water is able to form hydrogen bonds because A) oxygen has a valence of 2. B) the water molecule is shaped like a tetrahedron. C) the bonds that hold together the atoms in a water molecule are polar covalent bonds. D) the oxygen atom in a water molecule has a weak positive charge. E) each of the hydrogen atoms in a water molecule is weakly negative in charge.
Answer: C
4) What is the basis for the difference in how the leading and lagging strands of DNA molecules are synthesized? A) The origins of replication occur only at the 5ʹ end. B) Helicases and single-strand binding proteins work at the 5ʹ end. C) DNA polymerase can join new nucleotides only to the 3ʹ end of a growing strand. D) DNA ligase works only in the 3ʹ → 5ʹ direction. E) Polymerase can work on only one strand at a time.
Answer: C
4) Which observation suggested to Sutherland the involvement of a second messenger in epinephrineʹs effect on liver cells? A) Enzymatic activity was proportional to the amount of calcium added to a cell - free extract. B) Receptor studies indicated that epinephrine was a ligand. C) Glycogen breakdown was observed only when epinephrine was administered to intact cells. D) Glycogen breakdown was observed when epinephrine and glycogen phosphorylase were combined. E) Epinephrine was known to have different effects on different types of cells.
Answer: C
4) Which of the following types of molecules are the major structural components of the cell membrane? A) phospholipids and cellulose B) nucleic acids and proteins C) phospholipids and proteins D) proteins and cellulose E) glycoproteins and cholesterol
Answer: C
7) Which of the following statements is a logical consequence of the second law of thermodynamics? A) If the entropy of a system increases, there must be a corresponding decrease in the entropy of the universe. B) If there is an increase in the energy of a system, there must be a corresponding decrease in the energy of the rest of the universe. C) Every energy transfer requires activation energy from the environment. D) Every chemical reaction must increase the total entropy of the universe. E) Energy can be transferred or transformed, but it cannot be created or destroyed.
Answer: D
7) Which stratum should contain the greatest proportion of extinct organisms?
Answer: D
40) A patient has had a serious accident and lost a lot of blood. In an attempt to replenish body fluids, distilled water, equal to the volume of blood lost, is transferred directly into one of his veins. What will be the most probable result of this transfusion? A) It will have no unfavorable effect as long as the water is free of viruses and bacteria. B) The patientʹs red blood cells will shrivel up because the blood fluid is hypotonic compared to the cells. C) The patientʹs red blood cells will swell because the blood fluid is hypotonic compared to the cells. D) The patientʹs red blood cells will shrivel up because the blood fluid is hypertonic compared to the cells. E) The patientʹs red blood cells will burst because the blood fluid is hypertonic compared to the cells.
Answer: C
40) Collecting data based on observation is an example of __________; analyzing this data to reach a conclusion is an example of __________ reasoning. A) hypothesis-based science; inductive B) the process of science; deductive C) discovery science; inductive D) descriptive science; deductive E) hypothesis-based science; deductive
Answer: C
59) Differentiation of cells is not easily reversible because it involves A) changes in the nucleotide sequence of genes within the genome. B) changes in chromatin structure that make certain regions of the genome more accessible. C) chemical modifications of histones and DNA methylation. D) frameshift mutations and inversions. E) excision of some coding sequences.
Answer: D
59) Which of the following statements describes the eukaryotic chromosome? A) It is composed of DNA alone. B) The nucleosome is its most basic functional subunit. C) The number of genes on each chromosome is different in different cell types of an organism. D) It consists of a single linear molecule of double-stranded DNA. E) Active transcription occurs on heterochromatin.
Answer: D
41) A covalent chemical bond is one in which A) electrons are removed from one atom and transferred to another atom so that the two atoms become oppositely charged. B) protons and neutrons are shared by two atoms so as to satisfy the requirements of both atoms. C) outer-shell electrons of two atoms are shared so as to satisfactorily fill the outer electron shells of both atoms. D) outer-shell electrons of one atom are transferred to the inner electron shells of another atom. E) the inner-shell electrons of one atom are transferred to the outer shell of another atom.
Answer: C
41) A major evolutionary episode that corresponds in time most closely with the formation of Pangaea was the A) origin of humans. B) Cambrian explosion. C) Permian extinctions. D) Pleistocene ice ages. E) Cretaceous extinctions.
Answer: C
41) A particular triplet of bases in the coding sequence of DNA is AAA. The anticodon on the tRNA that binds the mRNA codon is A) TTT. B) UUA. C) UUU. D) AAA. E) either UAA or TAA, depending on first base wobble.
Answer: C
6) A woman is found to have 47 chromosomes, including 3 X chromosomes. Which of the following describes her expected phenotype? A) Masculine characteristics such as facial hair B) Enlarged genital structures C) Excessive emotional instability D) Normal female E) Sterile female
Answer: D
41) Celery stalks that are immersed in fresh water for several hours become stiff and hard. Similar stalks left in a salt solution become limp and soft. From this we can deduce that the cells of the celery stalks are A) hypotonic to both fresh water and the salt solution. B) hypertonic to both fresh water and the salt solution. C) hypertonic to fresh water but hypotonic to the salt solution. D) hypotonic to fresh water but hypertonic to the salt solution. E) isotonic with fresh water but hypotonic to the salt solution.
Answer: C
41) Gene expression might be altered at the level of post - transcriptional processing in eukaryotes rather than prokaryotes because of which of the following? A) Eukaryotic mRNAs get 5ʹ caps and 3ʹ tails. B) Prokaryotic genes are expressed as mRNA, which is more stable in the cell. C) Eukaryotic exons may be spliced in alternative patterns. D) Prokaryotes use ribosomes of different structure and size. E) Eukaryotic coded polypeptides often require cleaving of signal sequences before localization.
Answer: C
41) If the pH of a solution is increased from pH 5 to pH 7, it means that the A) concentration of H + is twice (2X) what it was at pH 5. B) concentration of H + is half (1/2) what it was at pH 5. C) concentration of OH- is 100 times greater than what it was at pH 5. D) concentration of OH- is one-hundredth (0.01X) what it was at pH 5. E) concentration of H + is 100 times greater and the concentration of OH - is one-hundredth what they were at pH 5.
Answer: C
41) Upon chemical analysis, a particular polypeptide was found to contain 100 amino acids. How many peptide bonds are present in this protein? A) 101 B) 100 C) 99 D) 98 E) 97
Answer: C
41) Which of the following covalently connects segments of DNA? A) helicase B) DNA polymerase III C) ligase D) DNA polymerase I E) primase
Answer: C
41) Which of the following is a correct association? A) kinase activity and the addition of a tyrosine B) phosphodiesterase activity and the removal of phosphate groups C) GTPase activity and hydrolysis of GTP to GDP D) phosphorylase activity and the catabolism of glucose E) adenylyl cyclase activity and the conversion of cAMP to AMP
Answer: C
42) On the basis of their morphologies, how might Linnaeus have classified the Hawaiian silverswords? A) He would have placed them all in the same species. B) He would have classified them the same way that modern botanists do. C) He would have placed them in more species than modern botanists do. D) He would have used evolutionary relatedness as the primary criterion for their classification. E) Both B and D are correct.
Answer: C
42) The research team used the setup to study the incorporation of labeled nucleotides into a culture of lymphocytes and found that the lymphocytes incorporated the labeled nucleotide at a significantly higher level after a pathogen was introduced into the culture. They concluded that A) the presence of the pathogen made the experiment too contaminated to trust the results. B) their tissue culture methods needed to be relearned. C) infection causes lymphocytes to divide more rapidly. D) infection causes cell cultures in general to reproduce more rapidly. E) infection causes lymphocyte cultures to skip some parts of the cell cycle.
Answer: C
42) Two blue budgies were crossed. Over the years, they produced 22 offspring, 5 of which were white. What are the most likely genotypes for the two blue budgies? A) yyBB and yyBB B) yyBB and yyBb C) yyBb and yyBb D) yyBB and yybb E) yyBb and yybb
Answer: C
42) Which of the following techniques used to analyze gene function depends on the specificity of DNA base complementarity? A) Northern blotting B) use of RNAi C) in vitro mutagenesis D) in situ hybridization E) restriction fragment analysis
Answer: C
42) Which sample might represent a sperm cell? A) I B) II C) III D) Either I or II E) Either II or III
Answer: C
43) A drug designed to inhibit the response of cells to testosterone would almost certainly result in which of the following? A) lower cytoplasmic levels of cAMP B) an increase in receptor tyrosine kinase activity C) a decrease in transcriptional activity of certain genes D) an increase in cytosolic calcium concentration E) a decrease in G-protein activity
Answer: C
43) Increasing the substrate concentration in an enzymatic reaction could overcome which of the following? A) denaturization of the enzyme B) allosteric inhibition C) competitive inhibition D) saturation of the enzyme activity E) insufficient cofactors
Answer: C
43) Over evolutionary time, many cave-dwelling organisms have lost their eyes. Tapeworms have lost their digestive systems. Whales have lost their hind limbs. How can natural selection account for these losses? A) Natural selection cannot account for losses, only for innovations. B) Natural selection accounts for these losses by the principle of use and disuse. C) Under particular circumstances that persisted for long periods, each of these structures presented greater costs than benefits. D) The ancestors of these organisms experienced harmful mutations that forced them to find new habitats that these species had not previously used.
Answer: C
6) How do the daughter cells at the end of mitosis and cytokinesis compare with their parent cell when it was in G1 of the cell cycle? A) The daughter cells have half the amount of cytoplasm and half the amount of DNA. B) The daughter cells have half the number of chromosomes and half the amount of DNA. C) The daughter cells have the same number of chromosomes and half the amount of DNA. D) The daughter cells have the same number of chromosomes and the same amount of DNA. E) The daughter cells have the same number of chromosomes and twice the amount of DNA.
Answer: D
44) A controlled experiment is one in which A) the experiment is repeated many times to ensure that the results are accurate. B) the experiment proceeds at a slow pace to guarantee that the scientist can carefully observe all reactions and process all experimental data. C) there are at least two groups, one of which does not receive the experimental treatment. D) there are at least two groups, one differing from the other by two or more variables. E) there is one group for which the scientist controls all variables.
Answer: C
6) How many grams of acetic acid (C 2H4O2 ) would you use to make 10 L of a 0.1 M aqueous solution of acetic acid? (Note: The atomic masses, in daltons, are approximately 12 for carbon, 1 for hydrogen, and 16 for oxygen.) A) 10.0 g B) 0.1 g C) 6.0 g D) 60.0 g E) 0.6 g
Answer: D
45) According to the concept of punctuated equilibrium, A) natural selection is unimportant as a mechanism of evolution. B) given enough time, most existing species will branch gradually into new species. C) a new species accumulates most of its unique features as it comes into existence. D) evolution of new species features long periods during which changes are occurring, interspersed with short periods of equilibrium, or stasis. E) transitional fossils, intermediate between newer species and their parent species, should be abundant.
Answer: C
45) Where are the proteins of the electron transport chain located? A) cytosol B) mitochondrial outer membrane C) mitochondrial inner membrane D) mitochondrial intermembrane space E) mitochondrial matrix
Answer: C
45) Which of the following problems with animal cloning might result in premature death of the clones? A) use of pluripotent instead of totipotent stem cells B) use of nuclear DNA as well as mtDNA C) abnormal regulation due to variant methylation D) the indefinite replication of totipotent stem cells E) abnormal immune function due to bone marrow dysfunction
Answer: C
45) Which of these is the most likely explanation for the modern -day distribution of dicynodont fossils? A) There had been two previous super -continents that existed at different times long before the Permian period. B) The dicynodonts were evenly distributed throughout all of Pangaea. C) The dicynodonts were distributed more abundantly throughout Gondwanaland than throughout any other land mass. D) The dicynodonts were able to swim long distances, up to thousands of kilometers. E) The dicynodonts could survive for periods of months aboard ʺraftsʺ of vegetation, which carried them far and wide, but not to the northern hemisphere.
Answer: C
46) Based on this information, which of the following is correct? A) Succinate dehydrogenase is the enzyme, and fumarate is the substrate. B) Succinate dehydrogenase is the enzyme, and malonic acid is the substrate. C) Succinate is the substrate, and fumarate is the product. D) Fumarate is the product, and malonic acid is a noncompetitive inhibitor. E) Malonic acid is the product, and fumarate is a competitive inhibitor.
Answer: C
46) The use of beta 2 antagonist drugs may be useful in asthma because A) they may increase constriction of the skeletal muscle of the chest wall. B) they may increase heart rate and therefore allow the patient to get more oxygen circulated. C) they may dilate the bronchioles by relaxing their smooth muscle. D) they may override the beta blockers that the patient is already taking. E) they may obstruct all G protein-mediated receptors.
Answer: C
46) Which is an acidic functional group that can dissociate and release H + into a solution?
Answer: C
46) Which line represents the bag that contained a solution isotonic to the 0.6 molar solution at the beginning of the experiment?
Answer: C
46) Which of the following statements most detracts from the claim that the human appendix is a completely vestigial organ? A) The appendix can be surgically removed with no immediate ill effects. B) The appendix might have been larger in fossil hominids. C) The appendix has a substantial amount of defensive lymphatic tissue. D) Individuals with a larger - than-average appendix leave fewer offspring than those with a below-average-sized appendix. E) In a million years, the human species might completely lack an appendix.
Answer: C
46) Women with Turner syndrome have a genotype characterized as which of the following? A) aabb B) Mental retardation and short arms C) A karyotype of 45, X D) A karyotype of 47, XXX E) A deletion of the Y chromosome
Answer: C
47) One of the hopes for use of recent knowledge gained about non -coding RNAs lies with the possibilities for their use in medicine. Of the following scenarios for future research, which would you expect to gain most from RNAs? A) exploring a way to turn on the expression of pseudogenes B) targeting siRNAs to disable the expression of an allele associated with autosomal recessive disease C) targeting siRNAs to disable the expression of an allele associated with autosomal dominant disease D) creating knock-out organisms that can be useful for pharmaceutical drug design E) looking for a way to prevent viral DNA from causing infection in humans
Answer: C
47) Whether during mitosis or meiosis, sister chromatids are held together by proteins referred to as cohesions. Such molecules must have which of the following properties? A) They must persist throughout the cell cycle. B) They must be removed before meiosis can begin. C) They must be removed before anaphase can occur. D) They must reattach to chromosomes during G1. E) They must be intact for nuclear envelope reformation.
Answer: C
47) Which of these is the most likely explanation for the existence of dicynodont fossils on modern-day Antarctica? A) They arrived there aboard ʺraftsʺ of vegetation, and quickly adapted to the bitterly cold climate. B) Earthʹs polar regions were once so warm (especially immediately after the ʺsnowball Earth periodʺ) that reptiles and mammal - like reptiles flourished there. C) The landmass that is now the Antarctic continent was formerly located at a more-northerly position, and was also united to other landmasses. D) Dicynodonts originated on the island continent of Antarctica and went extinct as the continent migrated to its current position at the South Pole.
Answer: C
48) Experiments with cohesions have found that A) cohesions are protected from destruction throughout meiosis I and II. B) cohesions are cleaved from chromosomes at the centromere before anaphase I. C) cohesions are protected from cleavage at the centromere during meiosis I. D) a protein cleaves cohesions before metaphase I. E) a protein that cleaves cohesions would cause cellular death.
Answer: C
48) What are scaffolding proteins? A) ladder- like proteins that allow receptor- ligand complexes to climb through cells from one position to another B) microtubular protein arrays that allow lipid-soluble hormones to get from the cell membrane to the nuclear pores C) large molecules to which several relay proteins attach to facilitate cascade effects D) relay proteins that orient receptors and their ligands in appropriate directions to facilitate their complexing E) proteins that can reach into the nucleus of a cell to affect transcription
Answer: C
48) What is the role of DNA ligase in the elongation of the lagging strand during DNA replication? A) synthesize RNA nucleotides to make a primer B) catalyze the lengthening of telomeres C) join Okazaki fragments together D) unwind the parental double helix E) stabilize the unwound parental DNA
Answer: C
48) Which describes the ability of a single gene to have multiple phenotypic effects? A) Incomplete dominance B) Multiple alleles C) Pleiotropy D) Epistasis
Answer: C
49) In a series of experiments, the enzyme Dicer has been inactivated in cells from various vertebrates, and the centromere is abnormally formed from chromatin. Which of the following is most likely to occur? A) The usual mRNAs transcribed from centromeric DNA will be missing from the cells. B) Tetrads will no longer be able to form during meiosis I. C) Centromeres will be euchromatic rather than heterochromatic and the cells will soon die in culture. D) The cells will no longer be able to resist bacterial contamination. E) The DNA of the centromeres will no longer be able to replicate.
Answer: C
49) Upon undergoing change, which of these genes is most likely to result in speciation while a geographic barrier separates two populations of a flowering -plant species? A) one that affects the rate of chlorophyll a synthesis B) one that affects the amount of growth hormone synthesized per unit time C) one that affects the compatibility of male pollen and female reproductive parts D) one that affects the average depth to which roots grow down through the soil E) one that affects how flexible the stems are
Answer: C
5) A genetic change that caused a certain Hox gene to be expressed along the tip of a vertebrate limb bud instead of farther back helped to make possible the evolution of the tetrapod limb. This type of change is illustrative of A) the influence of environment on development. B) paedomorphosis. C) a change in a developmental gene or in its regulation that altered the spatial organization of body parts. D) heterochrony. E) gene duplication.
Answer: C
5) Absence of bicoid mRNA from a Drosophila egg leads to the absence of anterior larval body parts and mirror- image duplication of posterior parts. This is evidence that the product of the bicoid gene A) is transcribed in the early embryo. B) normally leads to formation of tail structures. C) normally leads to formation of head structures. D) is a protein present in all head structures. E) leads to programmed cell death.
Answer: C
5) Each element is unique and different from other elements because of the number of protons in the nuclei of its atoms. Which of the following indicates the number of protons in an atomʹs nucleus? A) atomic mass B) atomic weight C) atomic number D) mass weight E) mass number
Answer: C
5) Protein phosphorylation is commonly involved with all of the following except A) regulation of transcription by extracellular signal molecules. B) enzyme activation. C) activation of G protein-coupled receptors. D) activation of receptor tyrosine kinases. E) activation of protein kinase molecules.
Answer: C
5) Protists and bacteria are grouped into different domains because A) protists eat bacteria. B) bacteria are not made of cells. C) protists have a membrane -bounded nucleus, which bacterial cells lack. D) bacteria decompose protists. E) protists are photosynthetic.
Answer: C
5) The decline of MPF activity at the end of mitosis is due to A) the destruction of the protein kinase Cdk. B) decreased synthesis of cyclin. C) the degradation of cyclin. D) synthesis of DNA. E) an increase in the cellʹs volume- to-genome ratio.
Answer: C
5) To cause a human pandemic, the H5N1 avian flu virus would have to A) spread to primates such as chimpanzees. B) develop into a virus with a different host range. C) become capable of human- to-human transmission. D) arise independently in chickens in North and South America. E) become much more pathogenic.
Answer: C
5) Two eukaryotic proteins have one domain in common but are otherwise very different. Which of the following processes is most likely to have contributed to this phenomenon? A) gene duplication B) RNA splicing C) exon shuffling D) histone modification E) random point mutations
Answer: C
5) What is the most logical sequence of steps for splicing foreign DNA into a plasmid and inserting the plasmid into a bacterium? I. Transform bacteria with recombinant DNA molecule. II. Cut the plasmid DNA using restriction enzymes. III. Extract plasmid DNA from bacterial cells. IV. Hydrogen -bond the plasmid DNA to nonplasmid DNA fragments. V. Use ligase to seal plasmid DNA to nonplasmid DNA. A) I, II, IV, III, V B) II, III, V, IV, I C) III, II, IV, V, I D) III, IV, V, I, II E) IV, V, I, II, III
Answer: C
50) During oxidative phosphorylation, H 2O is formed. Where does the oxygen for the synthesis of the water come from? A) carbon dioxide (CO2 ) B) glucose (C6H12O6 ) C) molecular oxygen (O2 ) D) pyruvate (C3H3O3- ) E) lactate (C3H5O3- )
Answer: C
51) Cystic fibrosis affects the lungs, the pancreas, the digestive system, and other organs, resulting in symptoms ranging from breathing difficulties to recurrent infections. Which of the following terms best describes this? A) Incomplete dominance B) Multiple alleles C) Pleiotropy D) Epistasis
Answer: C
51) If a female of this species has one chromosome 12 with a blue gene and another chromosome 12 with an orange gene, she will produce which of the following egg types? A) Only blue gene eggs B) Only orange gene eggs C) 1/2 blue and 1/2 orange gene eggs D) 3/4 blue and 1/4 orange gene eggs E) An indeterminate frequency of blue and orange gene eggs
Answer: C
51) Pure, freshly-distilled water has a pH of 7. This means that A) there are no H+ ions in the water. B) there are no OH- ions in the water. C) the concentration of H+ ions in the water equals the concentration of OH - ions in the water. D) the concentration of H+ ions in the water is 7 times the concentration of OH - ions in the water. E) The concentration of OH- ions in the water is 7 times the concentration of H + ions in the water.
Answer: C
51) The researcher in question measures the amount of new polypeptide production in embryos from 2—8 hours following fertilization and the results show a steady and significant rise in polypeptide concentration over that time. The researcher concludes that A) his measurement skills must be faulty. B) the results are due to building new cell membranes to compartmentalize dividing nuclei. C) the resulting new polypeptides are due to translation of maternal mRNAs. D) the new polypeptides were inactive and not measurable until fertilization. E) polypeptides were attached to egg membranes until this time.
Answer: C
51) Which molecule has a carbonyl functional group in the form of a ketone?
Answer: C
52) Which of the following membrane activities require energy from ATP hydrolysis? A) facilitated diffusion. B) movement of water into a cell C) Na+ ions moving out of the cell D) movement of glucose molecules E) movement of water into a paramecium
Answer: C
53) The tertiary structure of a protein is the A) bonding together of several polypeptide chains by weak bonds. B) order in which amino acids are joined in a polypeptide chain. C) unique three-dimensional shape of the fully folded polypeptide. D) organization of a polypeptide chain into an α helix or β pleated sheet. E) overall protein structure resulting from the aggregation of two or more polypeptide subunits.
Answer: C
53) What is the difference between covalent bonds and ionic bonds? A) Covalent bonds involve the sharing of protons between atoms, and ionic bonds involve the sharing of electrons between atoms. B) Covalent bonds involve the sharing of neutrons between atoms, and ionic bonds involve the sharing of electrons between atoms. C) Covalent bonds involve the sharing of electrons between atoms, and ionic bonds involve the electrical attraction between atoms. D) Covalent bonds involve the sharing of protons between atoms, and ionic bonds involve the sharing of neutrons between atoms. E) Covalent bonds involve the transfer of electrons between atoms, and ionic bonds involve the sharing of neutrons between atoms.
Answer: C
54) If an adult person has a faulty version of the human -analog to ced-4 of the nematode, which of the following might more likely result? A) neurodegeneration B) activation of a developmental pathway found in the worm but not in humans C) a form of cancer in which there is insufficient apoptosis D) webbing of fingers or toes E) excess skin exfoliation
Answer: C
54) Which of the following provides an example of epistasis? A) Recessive genotypes for each of two genes (aabb) results in an albino corn snake. B) The allele b17 produces a dominant phenotype, although b1 through b16 do not. C) In rabbits and many other mammals, one genotype ( cc ) prevents any fur color from developing. D) In Drosophila (fruit flies), white eyes can be due to an X- linked gene or to a combination of other genes.
Answer: C
54) Which of the following statements about the cytoskeleton is true? A) The dynamic aspect of cytoskeletal function is made possible by the assembly and disassembly of a large number of complex proteins into larger aggregates. B) Microfilaments are structurally rigid and resist compression, while microtubules resist tension (stretching). C) Movement of cilia and flagella is the result of motor proteins causing microtubules to move relative to each other. D) Chemicals that block the assembly of the cytoskeleton would cause little effect on the cellʹs metabolism E) Transport vesicles among the membranes of the endomembrane system produce the cytoskeleton.
Answer: C
55) At which level of protein structure are interactions between the side chains (R groups) most important? A) primary B) secondary C) tertiary D) quaternary E) all of the above
Answer: C
55) Equal volumes of vinegar from a freshly-opened bottle are added to each of the following solutions. After complete mixing, which of the mixtures will have the highest pH? A) 100 mL of pure water B) 100 mL of freshly-brewed coffee C) 100 mL of household cleanser containing 0.5M ammonia D) 100 mL of freshly-squeezed orange juice E) 100 mL of tomato juice
Answer: C
56) About how many more genes are there in the haploid human genome than in a typical bacterial genome? A) 10 X B) 100 X C) 1000 X D) 10,000 X E) 100,000 X
Answer: C
56) All of the following serve an important role in determining or maintaining the structure of plant cells. Which of the following are distinct from the others in their composition? A) microtubules B) microfilaments C) plant cell walls D) intermediate filaments E) nuclear lamina
Answer: C
56) Huntingtonʹs disease is a dominant condition with late age of onset in humans. If one parent has the disease, what is the probability that his or her child will have the disease? A) 1 B) 3/4 C) 1/2 D) 1/4 E) 0
Answer: C
56) One successful form of gene therapy has involved delivery of an allele for the enzyme adenosine deaminase (ADA) to bone marrow cells of a child with SCID, and delivery of these engineered cells back to the bone marrow of the affected child. What is one major reason for the success of this procedure as opposed to many other efforts at gene therapy? A) The engineered bone marrow cells from this patient can be used for any other SCID patient. B) The ADA introduced allele causes all other ADA-negative cells to die. C) The engineered cells, when reintroduced into the patient, find their way back to the bone marrow. D) No vector is required to introduce the allele into ADA -negative cells E) The immune system fails to recognize cells with the variant gene
Answer: C
56) Which addition to the information in the paragraph above would make more than one of the answers listed in the previous question correct? A) If larynx size was also affected by the amount the larynx was used (i.e., the amount of vocalization). B) If males prefer to mate with females possessing higher voices. C) If females killed female offspring whose voices were too deep. D) If the trend described above was seen in the fossil record of only one species of ape.
Answer: C
56) Which of the following results from a transfer of electron(s) between atoms? A) nonpolar covalent bond B) polar covalent bond C) ionic bond D) hydrogen bond E) hydrophobic interaction
Answer: C
6) Quantum dots are small (15—30 nm diameter), bright particles visible using light microscopy. If the dots can be specifically bound to individual proteins on a plasma membrane of a cell, which of the following correctly describes the advantage of using quantum dots in examining proteins? A) The dots permit the position of the proteins to be determined more precisely. B) The dots permit the average distance between the proteins to be determined more precisely. C) The dots permit the size of the proteins to be determined more precisely. D) The dots permit the motion of the proteins to be determined more precisely. E) The dots permit visualization of proteins interacting with lipids.
Answer: D
6) The elongation of the leading strand during DNA synthesis A) progresses away from the replication fork. B) occurs in the 3ʹ → 5ʹ direction. C) produces Okazaki fragments. D) depends on the action of DNA polymerase. E) does not require a template strand.
Answer: D
6) Whenever energy is transformed, there is always an increase in the A) free energy of the system. B) free energy of the universe. C) entropy of the system. D) entropy of the universe. E) enthalpy of the universe.
Answer: D
56) You have two beakers; one contains pure water, the other contains pure methanol (wood alcohol). The covalent bonds of methanol molecules are nonpolar, so there are no hydrogen bonds among methanol molecules. You pour crystals of table salt (NaCl) into each beaker. Predict what will happen. A) Equal amounts of NaCl crystals will dissolve in both water and methanol. B) NaCl crystals will NOT dissolve in either water or methanol. C) NaCl crystals will dissolve readily in water but will not dissolve in methanol. D) NaCl crystals will dissolve readily in methanol but will not dissolve in water. E) When the first crystals of NaCl are added to water or to methanol, they will not dissolve; but as more crystals are added, the crystals will begin to dissolve faster and faster.
Answer: C
57) A woman has six sons. The chance that her next child will be a daughter is A) 1. B) 0. C) 1/2. D) 1/6. E) 5/6.
Answer: C
57) Each time a molecule of glucose (C 6H12O6 ) is completely oxidized via aerobic respiration, how many oxygen molecules (O2 ) are required? A) 1 B) 2 C) 6 D) 12 E) 38
Answer: C
57) If one excludes the involvement of gender in the situation described in the paragraph above, then the pattern that is apparent in the fossil record is most similar to one that should be expected from A) pansexual selection. B) directional selection. C) disruptive selection. D) stabilizing selection. E) asexual selection.
Answer: C
57) The sodium-potassium pump is called an electrogenic pump because it A) pumps equal quantities of Na+ and K+ across the membrane. B) pumps hydrogen ions out of the cell. C) contributes to the membrane potential. D) ionizes sodium and potassium atoms. E) is used to drive the transport of other molecules against a concentration gradient.
Answer: C
57) When a tRNA molecule is shown twisted into an L shape, the form represented is A) its linear sequence. B) its 2-dimensional shape. C) its 3-dimensional shape. D) its microscopic image.
Answer: C
57) You have two beakers. One contains a solution of HCl at pH = 1.0. The other contains a solution of NaOH at pH = 13. Into a third beaker, you slowly and cautiously pour 20 mL of the HCL and 20 mL of the NaOH. After complete stirring, the pH of the mixture will be A) 2.0. B) 12.0. C) 7.0. D) 5.0. E) 9.0.
Answer: C
6) Which of the following pairs of base sequences could form a short stretch of a normal double helix of DNA? A) 5ʹ-purine-pyrimidine-purine-pyrimidine-3ʹ with 3ʹ-purine-pyrimidine-purine-pyrimidine-5ʹ B) 5ʹ-A-G-C-T-3ʹ with 5ʹ -T-C-G-A-3ʹ C) 5ʹ-G-C-G-C-3ʹ with 5ʹ -T-A-T-A-3ʹ D) 5ʹ-A-T-G-C-3ʹ with 5ʹ -G-C-A-T-3ʹ E) All of these pairs are correct.
Answer: D
58) A cell that remains entirely flexible in its developmental possibilities is said to be A) differentiated. B) determined. C) totipotent. D) genomically equivalent. E) epigenetic.
Answer: C
58) An experimenter has altered the 3ʹ end of the tRNA corresponding to the amino acid methionine in such a way as to remove the 3ʹ AC. Which of the following hypotheses describes the most likely result? A) tRNA will not form a cloverleaf. B) The nearby stem end will pair improperly. C) The amino acid methionine will not bind. D) The anticodon will not bind with the mRNA codon. E) The aminoacylsynthetase will not be formed.
Answer: C
58) What is the genotype of individual II -5? A) WW B) Ww C) ww D) WW or ww E) ww or Ww
Answer: C
6) Which of the following pairs of structures is least likely to represent homology? A) The wings of a bat and the arms of a human B) The hemoglobin of a baboon and that of a gorilla C) The mitochondria of a plant and those of an animal D) The wings of a bird and those of an insect E) The brain of a cat and that of a dog
Answer: D
6) Which of the following statements is a correct distinction between autotrophs and heterotrophs? A) Only heterotrophs require chemical compounds from the environment. B) Cellular respiration is unique to heterotrophs. C) Only heterotrophs have mitochondria. D) Autotrophs, but not heterotrophs, can nourish themselves beginning with CO 2 and other nutrients that are inorganic. E) Only heterotrophs require oxygen.
Answer: D
6) Which of the following steps has not yet been accomplished by scientists studying the origin of life? A) synthesis of small RNA polymers by ribozymes B) abiotic synthesis of polypeptides C) formation of molecular aggregates with selectively permeable membranes D) formation of protobionts that use DNA to direct the polymerization of amino acids E) abiotic synthesis of organic molecules
Answer: D
60) Assume a mitochondrion contains 58 NADH and 19 FADH 2 . If each of the 77 dinucleotides were used, approximately how many ATP molecules could be generated as a result of oxidative phosphorylation (chemiosmosis)? A) 36 B) 77 C) 173 D) 212 E) 1102
Answer: D
60) Ions diffuse across membranes down their A) chemical gradients. B) concentration gradients. C) electrical gradients. D) electrochemical gradients. E) A and B are correct.
Answer: D
60) Mitochondrial DNA is primarily involved in coding for proteins needed for electron transport. Therefore in which body systems would you expect most mitochondrial gene mutations to be exhibited? A) The immune system and the blood B) Excretory and respiratory systems C) The skin and senses D) Nervous and muscular systems E) Circulation
Answer: D
60) Where does tRNA #2 move to after this bonding of lysine to the polypeptide? A) A site B) P site C) E site D) Exit tunnel E) Directly to the cytosol
Answer: D
71) Which of the following is true for this reaction? 3 H 2 + N2 ↔ 2 NH3 A) The reaction is nonreversible. B) Hydrogen and nitrogen are the reactants of the reverse reaction. C) Hydrogen and nitrogen are the products of the forward reaction. D) Ammonia is being formed and decomposed. E) Hydrogen and nitrogen are being decomposed.
Answer: D
73) The existence of evolutionary trends, such as increasing body sizes among horse species, is evidence that A) a larger volume- to-surface area ratio is beneficial to all mammals. B) an unseen guiding force is at work. C) evolution always tends toward increased complexity or increased size. D) in particular environments, similar adaptations can be beneficial in more than one species. E) evolution generally progresses toward some predetermined goal.
Answer: D
59) The movement of potassium into an animal cell requires A) low cellular concentrations of sodium. B) high cellular concentrations of potassium. C) an energy source such as ATP or a proton gradient. D) a cotransport protein. E) a gradient of protons across the plasma membrane.
Answer: C
59) When a potassium ion (K+ ) moves from the soil into the vacuole of a cell on the surface of a root, it must pass through several cellular structures. Which of the following correctly describes the order in which these structures will be encountered by the ion? A) plasma membrane → primary cell wall → cytoplasm → tonoplast B) secondary cell wall → plasma membrane → primary cell wall → cytoplasm → tonoplast C) primary cell wall → plasma membrane → cytoplasm → tonoplast D) primary cell wall → plasma membrane → tonoplast → cytoplasm → vacuole E) tonoplast → primary cell wall → plasma membrane → cytoplasm
Answer: C
6) According to the punctuated equilibria model, A) natural selection is unimportant as a mechanism of evolution. B) given enough time, most existing species will branch gradually into new species. C) most new species accumulate their unique features relatively rapidly as they come into existence, then change little for the rest of their duration as a species. D) most evolution occurs in sympatric populations. E) speciation is usually due to a single mutation.
Answer: C
6) Bacteria containing recombinant plasmids are often identified by which process? A) examining the cells with an electron microscope B) using radioactive tracers to locate the plasmids C) exposing the bacteria to an antibiotic that kills cells lacking the resistant plasmid D) removing the DNA of all cells in a culture to see which cells have plasmids E) producing antibodies specific for each bacterium containing a recombinant plasmid
Answer: C
75) These genes form gradients and help establish the axes and other features of an embryo: A) homeotic genes B) segmentation genes C) egg-polarity genes D) morphogens E) inducers
Answer: D
6) DNA technology has many medical applications. Which of the following is not done routinely at present? A) production of hormones for treating diabetes and dwarfism B) production of viral proteins for vaccines C) introduction of genetically engineered genes into human gametes D) prenatal identification of genetic disease genes E) genetic testing for carriers of harmful alleles
Answer: C
6) If we continued to follow the cell lineage from question 5, then the DNA content of a single cell at metaphase of meiosis II would be A) 0.25x . B) 0.5x . C) x . D) 2x . E) 4x .
Answer: C
6) In the mid-1900s, the Soviet geneticist Lysenko believed that his winter wheat plants, exposed to ever -colder temperatures, would eventually give rise to ever more cold- tolerant winter wheat. Lysenkoʹs attempts in this regard were most in agreement with the ideas of A) Cuvier. B) Hutton. C) Lamarck. D) Darwin. E) Plato.
Answer: C
6) The nitrogenous base adenine is found in all members of which group? A) proteins, triglycerides, and testosterone B) proteins, ATP, and DNA C) ATP, RNA, and DNA D) alpha glucose, ATP, and DNA E) proteins, carbohydrates, and ATP
Answer: C
6) When a glucose molecule loses a hydrogen atom as the result of an oxidation -reduction reaction, the molecule becomes A) dehydrogenated. B) hydrogenated. C) oxidized. D) reduced. E) an oxidizing agent.
Answer: C
6) Which cell would be best for studying lysosomes? A) muscle cell B) nerve cell C) phagocytic white blood cell D) leaf cell of a plant E) bacterial cell
Answer: C
6) Which of the following best demonstrates the unity among all organisms? A) matching DNA nucleotide sequences B) descent with modification C) the structure and function of DNA D) natural selection E) emergent properties
Answer: C
6) Which of the following people was the first to synthesize an organic compound, urea, from inorganic starting materials? A) Stanley Miller B) Jakob Berzelius C) Friedrich Wohler D) Hermann Kolbe E) August Kekulé
Answer: C
60) What method did Frederick Sanger use to elucidate the structure of insulin? A) X- ray crystallography B) bioinformatics C) analysis of amino acid sequence of small fragments D) NMR spectroscopy E) high-speed centrifugation
Answer: C
60) When you have a severe fever, what may be a grave consequence if this is not controlled? A) destruction of your enzymesʹ primary structure B) removal of amine groups from your proteins C) change in the folding of enzymes D) removal of the amino acids in active sites E) binding of enzymes to inappropriate substrates
Answer: C
61) As genetic technology makes testing for a wide variety of genotypes possible, which of the following is likely to be an increasingly troublesome issue? A) use of genotype information to provide positive identification of criminals B) using technology to identify genes that cause criminal behaviors C) the need to legislate for the protection of the privacy of genetic information D) discrimination against certain racial groups because of major genetic differences E) alteration of human phenotypes to prevent early disease
Answer: C
61) MPF reaches its threshold concentration at the end of this stage. A) I B) II C) III D) IV E) V
Answer: C
76) Fruit fly eyes are of the compound type, structurally very different from the camera - type eyes of mammals. Even the camera- type eyes of mollusks, such as octopi, are structurally quite different from those of mammals. Yet, fruit flies, octopi, and mammals possess very similar versions of Pax-6 . The fact that the same gene helps produce very different types of eyes is most likely due to A) the few differences in nucleotide sequence among the Pax-6 genes of these organisms. B) variations in the number of Pax-6 genes among these organisms. C) the independent evolution of this gene at many different times during animal evolution. D) differences in the control of Pax-6 expression among these organisms.
Answer: D
76) Which metabolic pathway is common to both cellular respiration and fermentation? A) the oxidation of pyruvate to acetyl CoA B) the citric acid cycle C) oxidative phosphorylation D) glycolysis E) chemiosmosis
Answer: D
62) Plasmodesmata in plant cells are most similar in function to which of the following structures in animal cells? A) peroxisomes B) desmosomes C) gap junctions D) extracellular matrix E) tight junctions
Answer: C
62) Recall that the complete oxidation of a mole of glucose releases 686 kcal of energy (Δ G = -686 kcal/mol). The phosphorylation of ADP to form ATP stores approximately 7.3 kcal per mole of ATP. What is the approximate efficiency of cellular respiration for a ʺmutantʺ organism that produces only 29 moles of ATP for every mole of glucose oxidized, rather than the usual 36 -38 moles of ATP? A) 0.4% B) 25% C) 30% D) 40% E) 60%
Answer: C
78) The bicoid gene product is normally localized to the anterior end of the embryo. If large amounts of the product were injected into the posterior end as well, which of the following would occur? A) The embryo would grow to an unusually large size. B) The embryo would grow extra wings and legs. C) The embryo would probably show no anterior development and die. D) Anterior structures would form in both sides of the embryo. E) The embryo would develop normally.
Answer: D
62) Testosterone and estradiol are male and female sex hormones, respectively, in many vertebrates. In what way(s) do these molecules differ from each other? A) Testosterone and estradiol are structural isomers but have the same molecular formula. B) Testosterone and estradiol are geometric isomers but have the same molecular formula. C) Testosterone and estradiol have different functional groups attached to the same carbon skeleton. D) Testosterone and estradiol have distinctly different chemical structures, with one including four fused rings of carbon atoms, while the other has three rings. E) Testosterone and estradiol are enantiomers of the same organic molecule.
Answer: C
64) Most Swiss starlings produce four to five eggs in each clutch. Those producing fewer or more than this have reduced fitness. Which of the following terms best describes this? A) artificial selection B) directional selection C) stabilizing selection D) disruptive selection E) sexual selection
Answer: C
64) The molecule shown here is the simplest of organic compounds. It is called A) a carbohydrate. B) carbon dioxide. C) methane. D) carbonic hydrate. E) methyl carbonate.
Answer: C
64) Which of the following statements is true of chromatin? A) Heterochromatin is composed of DNA, whereas euchromatin is made of DNA and RNA. B) Both heterochromatin and euchromatin are found in the cytoplasm. C) Heterochromatin is highly condensed, whereas euchromatin is less compact. D) Euchromatin is not transcribed, whereas heterochromatin is transcribed. E) Only euchromatin is visible under the light microscope.
Answer: C
65) An obstetrician knows that one of her patients is a pregnant woman whose fetus is at risk for a serious disorder that is detectable biochemically in fetal cells. The obstetrician would most reasonably offer which of the following procedures to her patient? A) CVS B) Ultrasound imaging C) Amniocentesis D) Fetoscopy E) X- ray
Answer: C
65) Which of the following statements describes enzyme cooperativity? A) A multi-enzyme complex contains all the enzymes of a metabolic pathway. B) A product of a pathway serves as a competitive inhibitor of an early enzyme in the pathway. C) A substrate molecule bound to an active site affects the active site of several subunits. D) Several substrate molecules can be catalyzed by the same enzyme. E) A substrate binds to an active site and inhibits cooperation between enzymes in a pathway.
Answer: C
8) In recombinant DNA methods, the term vector can refer to A) the enzyme that cuts DNA into restriction fragments. B) the sticky end of a DNA fragment. C) a RFLP marker. D) a plasmid used to transfer DNA into a living cell. E) a DNA probe used to identify a particular gene.
Answer: D
8) Oxygen has an atomic number of 8 and a mass number of 16. Thus, the atomic mass of an oxygen atom is A) exactly 8 grams. B) exactly 8 daltons. C) approximately 16 grams. D) approximately 16 daltons. E) 24 amu (atomic mass units).
Answer: D
8) Synaptic signaling between adjacent neurons is like hormone signaling in which of the following ways? A) It sends its signal molecules through the blood. B) It sends its signal molecules quite a distance. C) It requires calcium ions. D) It requires binding of a signaling molecule to a receptor. E) It persists over a long period.
Answer: D
61) If neutral variation is truly ʺneutral,ʺ then it should have no effect on A) nucleotide diversity. B) average heterozygosity. C) our ability to measure the rate of evolution. D) relative fitness. E) gene diversity.
Answer: D
8) What is the chromosomal system for determining sex in mammals? A) Haploid-diploid B) X-0 C) X-X D) X-Y E) Z-W
Answer: D
61) If the malesʹ halteres have species-specific size, shape, color, and use in courtship displays, and if the speciesʹ ranges overlap, then the speciation events may have been driven, at least in part, by which of the following? A) autopolyploidy B) allopolyploidy C) species selection D) sexual selection E) habitat differentiation
Answer: D
61) The extracellular matrix is thought to participate in the regulation of animal cell behavior by communicating information from the outside to the inside of the cell via which of the following? A) gap junctions B) the nucleus C) DNA and RNA D) integrins E) plasmodesmata
Answer: D
61) Which component of the complex described enters the exit tunnel through the large subunit of the ribosome? A) tRNA with attached lysine (#1) B) tRNA with polypeptide (#2) C) tRNA that no longer has attached amino acid D) newly formed polypeptide E) initiation and elongation factors
Answer: D
8) Which of the following best describes the logic of hypothesis -based science? A) If I generate a testable hypothesis, tests and observations will support it. B) If my prediction is correct, it will lead to a testable hypothesis. C) If my observations are accurate, they will support my hypothesis. D) If my hypothesis is correct, I can expect certain test results. E) If my experiments are set up right, they will lead to a testable hypothesis.
Answer: D
8) Which of the following people synthesized an organic compound, acetic acid, from inorganic substances that had been prepared directly from pure elements? A) Stanley Miller B) Jakob Berzelius C) Friedrich Wohler D) Hermann Kolbe E) August Kekulé
Answer: D
66) If the prokaryotic flagellum developed from assemblages of proteins that originally were not involved with cell motility but with some other function instead, then the modern prokaryotic flagellum is a(n) A) vestigial organ. B) adoption. C) exaptation. D) homogeneous organ. E) allometric organ.
Answer: C
66) Of the following molecules of the ECM, which is capable of transmitting signals between the ECM and the cytoskeleton? A) fibronectin B) proteoglycans C) integrins D) collagen E) middle lamella
Answer: C
66) The alternative pathways of photosynthesis using the C4 or CAM systems are said to be compromises. Why? A) Each one minimizes both water loss and rate of photosynthesis. B) C4 compromises on water loss and CAM compromises on photorespiration. C) Each one both minimizes photorespiration and optimizes the Calvin cycle. D) CAM plants allow more water loss, while C4 plants allow less CO 2 into the plant. E) C4 plants allow less water loss but Cam plants but allow more water loss.
Answer: C
66) The average birth weight for human babies is about 3 kg. Which of the following terms best describes this? A) artificial selection B) directional selection C) stabilizing selection D) disruptive selection E) sexual selection
Answer: C
66) The frequency of heterozygosity for the sickle cell anemia allele is unusually high, presumably because this reduces the frequency of malaria. Such a relationship is related to which of the following? A) Mendelʹs law of independent assortment B) Mendelʹs law of segregation C) Darwinʹs explanation of natural selection D) Darwinʹs observations of competition E) The malarial parasite changing the allele
Answer: C
67) Cystic fibrosis (CF) is a Mendelian disorder in the human population that is inherited as a recessive. Two normal parents have two children with CF. The probability of their next child being normal for this characteristic is which of the following? A) 0 B) 1/2 C) 1/4 D) 3/4 E) 1/8
Answer: C
67) If plant gene alterations cause the plants to be deficient in photorespiration, what would most probably occur? A) Cells would carry on more photosynthesis. B) Cells would carry on the Calvin cycle at a much slower rate. C) Less ATP would be generated. D) There would be more light- induced damage to the cells. E) More sugars would be produced.
Answer: C
67) What is the effect of a nonsense mutation in a gene? A) It changes an amino acid in the encoded protein. B) It has no effect on the amino acid sequence of the encoded protein. C) It introduces a premature stop codon into the mRNA. D) It alters the reading frame of the mRNA. E) It prevents introns from being excised.
Answer: C
68) Phenylketonuria (PKU) is a recessive human disorder in which an individual cannot appropriately metabolize a particular amino acid. This amino acid is not otherwise produced by humans. Therefore the most efficient and effective treatment is which of the following? A) Feed them the substrate that can be metabolized into this amino acid. B) Transfuse the patients with blood from unaffected donors. C) Regulate the diet of the affected persons to severely limit the uptake of the amino acid. D) Feed the patients the missing enzymes in a regular cycle, i.e., twice per week.
Answer: C
63) Proton pumps are used in various ways by members of every kingdom of organisms. What does this most probably mean? A) Proton pumps must have evolved before any living organisms were present on the earth. B) Proton pumps are fundamental to all cell types. C) The high concentration of protons in the ancient atmosphere must have necessitated a pump mechanism. D) Cells with proton pumps were maintained in each Kingdom by natural selection. E) Proton pumps are necessary to all cell membranes.
Answer: D
66) After the second agitation of the membrane vesicles, what must be lost from the membrane? A) the ability of NADH to transfer electrons to the first acceptor in the electron transport chain B) the prosthetic groups like heme from the transport system C) cytochromes D) ATP synthase, in whole or in part E) the contact required between inner and outer membrane surfaces
Answer: D
66) Which of the following is the most correct interpretation of the figure? A) Inorganic phosphate is created from organic phosphate. B) Energy from catabolism can be used directly for performing cellular work. C) ADP + Pi are a set of molecules that store energy for catabolism. D) ATP is a molecule that acts as an intermediary to store energy for cellular work. E) Pi acts as a shuttle molecule to move energy from ATP to ADP.
Answer: D
69) A particular cyclin called cyclin E forms a complex with a cyclin -dependent kinase called Cdk 2. This complex is important for the progression of the cell from G 1 into the S phase of the cell cycle. Which of the following statements is correct? A) The amount of cyclin E is greatest during the S phase. B) The amount of Cdk 2 is greater during G 1 compared to the S phase. C) The amount of cyclin E is highest during G1 . D) The amount of Cdk 2 is greatest during G 1 . E) The activity of the cyclin E/Cdk 2 complex is highest during G 2 .
Answer: C
69) An explanation for the evolution of insect wings suggests that wings began as lateral extensions of the body that were used as heat dissipaters for thermoregulation. When they had become sufficiently large, these extensions became useful for gliding through the air, and selection later refined them as flight -producing wings. If this hypothesis is correct, insect wings could best be described as A) adaptations. B) mutations. C) exaptations. D) isolating mechanisms. E) examples of natural selectionʹs predictive ability.
Answer: C
69) Each of the following options is a modification of the sentence THECATATETHERAT. Which of the following is analogous to a single substitution mutation? A) THERATATETHECAT B) THETACATETHERAT C) THECATARETHERAT D) THECATATTHERAT E) CATATETHERAT
Answer: C
8) Which of the following statements correctly defines a kilocalorie? A) the amount of heat required to raise the temperature of 1 g of water by 1°F B) the amount of heat required to raise the temperature of 1 g of water by 1°C C) the amount of heat required to raise the temperature of 1 kg of water by 1°F D) the amount of heat required to raise the temperature of 1 kg of water by 1°C E) the amount of heat required to raise the temperature of 1,000 g of water by 1°F
Answer: D
69) Hutchinson-Gilford progeria is an exceedingly rare human genetic disorder in which there is very early senility, and death, usually of coronary artery disease, at an average age of approximately 13. Patients, who look very old even as children, do not live to reproduce. Which of the following represents the most likely assumption? A) All cases must occur in relatives; therefore, there must be only one mutant allele. B) Successive generations of a family will continue to have more and more cases over time. C) The disorder may be due to mutation in a single protein -coding gene. D) Each patient will have had at least one affected family member in a previous generation. E) The disease is autosomal dominant.
Answer: C
69) The recessive allele that causes phenylketonuria (PKU) is harmful, except when an infantʹs diet lacks the amino acid, phenylalanine. What maintains the presence of this harmful allele in a populationʹs gene pool? A) heterozygote advantage B) stabilizing selection C) diploidy D) balancing selection
Answer: C
69) Which of the following descriptions best fits the class of molecules known as nucleotides? A) a nitrogenous base and a phosphate group B) a nitrogenous base and a pentose sugar C) a nitrogenous base, a phosphate group, and a pentose sugar D) a phosphate group and an adenine or uracil E) a pentose sugar and a purine or pyrimidine
Answer: C
69) Which of the following is an example of cooperativity? A) the binding of an end product of a metabolic pathway to the first enzyme that acts in the pathway B) protein function at one site affected by binding at another of its active sites C) a molecule binding at one unit of a tetramer allowing faster binding at each of the other three D) the effect of increasing temperature on the rate of an enzymatic reaction E) binding of an ATP molecule along with one of the substrate molecules in an active site
Answer: C
7) A geneʹs location along a chromosome is known as which of the following? A) Allele B) Sequence C) Locus D) Variant E) Trait
Answer: C
7) A swim bladder is a gas- filled sac that helps fish maintain buoyancy. The evolution of the swim bladder from lungs of an ancestral fish is an example of A) an evolutionary trend. B) paedomorphosis. C) exaptation. D) adaptive radiation. E) changes in the Hox gene expression.
Answer: C
7) If a modern electron microscope (TEM) can resolve biological images to the nanometer level, as opposed to the best light microscope, this is due to which of the following? A) The focal length of the electron microscope is significantly longer. B) Contrast is enhanced by staining with atoms of heavy metal. C) Electron beams have much shorter wavelengths than visible light. D) The electron microscope has much greater ratio of image size to real size. E) The electron microscope cannot image whole cells at one time.
Answer: C
7) The common housefly belongs to all of the following taxa. Assuming you had access to textbooks or other scientific literature, knowing which of the following should provide you with the most specific information about the common housefly? A) order Diptera B) family Muscidae C) genus Musca D) class Hexapoda E) phylum Arthropoda
Answer: C
7) Using a series of arrows, draw the branched metabolic reaction pathway described by the following statements, then answer the question at the end. · L can form either M or N. · M can form O. · O can form either P or R. · P can form Q. · R can form S. · O inhibits the reaction of L to form M. · Q inhibits the reaction of O to form P. · S inhibits the reaction of O to form R. Which reaction would prevail if both Q and S were present in the cell in high concentrations? A) L → M B) M → O C) L → N D) O → P E) R → S
Answer: C
7) What is the chemical mechanism by which cells make polymers from monomers? A) phosphodiester linkages B) hydrolysis C) dehydration reactions D) ionic bonding of monomers E) the formation of disulfide bridges between monomers
Answer: C
7) When a cell releases a signal molecule into the environment and a number of cells in the immediate vicinity respond, this type of signaling is A) typical of hormones. B) autocrine signaling. C) paracrine signaling. D) endocrine signaling. E) synaptic signaling.
Answer: C
7) When a molecule of NAD+ (nicotinamide adenine dinucleotide) gains a hydrogen atom (not a hydrogen ion) the molecule becomes A) hydrogenated. B) oxidized. C) reduced. D) redoxed. E) a reducing agent.
Answer: C
7) Which of the following is an example of qualitative data? A) The temperature decreased from 20°C to 15°C. B) The plantʹs height is 25 centimeters (cm). C) The fish swam in a zig-zag motion. D) The six pairs of robins hatched an average of three chicks. E) The contents of the stomach are mixed every 20 seconds.
Answer: C
7) Which of the following sequences in double-stranded DNA is most likely to be recognized as a cutting site for a restriction enzyme? A) AAGG TTCC B) AGTC TCAG C) GGCC CCGG D) ACCA TGGT E) AAAA TTTT
Answer: C
7) Which of these is a correct representation of the hierarchy of biological organization from least to most complex? A) organelle of a stomach cell, digestive system, large intestine, small intestine, intestinal tissue, organism B) organelle of an intestinal cell, digestive system, small intestine, large intestine, intestinal tissue, organism C) molecule, intestinal cell organelle, intestinal cell, intestinal tissue, digestive system, organism D) molecule, small intestine, large intestine, intestinal tissue, digestive system, organism E) molecule, digestive system, digestive cell organelle, small intestine, large intestine, intestinal cell, organism
Answer: C
71) Cells from an advanced malignant tumor most often have very abnormal chromosomes, and often an abnormal total number of chromosomes. Why might this occur? A) Cancer cells are no longer density dependent. B) Cancer cells are no longer anchorage dependent. C) Chromosomally abnormal cells can still go through cell cycle checkpoints. D) Chromosomally abnormal cells still have normal metabolism. E) Transformation introduces new chromosomes into cells.
Answer: C
71) Many species of snakes lay eggs, but in the forests of northern Minnesota where growing seasons are short, only live-bearing snake species are present. This trend toward species that perform live birth is an example of A) natural selection. B) sexual selection. C) species selection. D) goal direction in evolution. E) directed selection.
Answer: C
71) What happens at the end of the chain? A) The 2 original electrons combine with NAD+ . B) The 2 original electrons combine with oxygen. C) 4 electrons combine with oxygen and protons. D) 4 electrons combine with hydrogen and oxygen atoms. E) 1 electron combines with oxygen and hydrogen.
Answer: C
72) Besides the ability of some cancer cells to overproliferate, what else could logically result in a tumor? A) metastasis B) changes in the order of cell cycle stages C) lack of appropriate cell death D) inability to form spindles E) inability of chromosomes to meet at the metaphase plate
Answer: C
8) Which of the following statements is representative of the second law of thermodynamics? A) Conversion of energy from one form to another is always accompanied by some gain of free energy. B) Heat represents a form of energy that can be used by most organisms to do work. C) Without an input of energy, organisms would tend toward decreasing entropy. D) Cells require a constant input of energy to maintain their high level of organization. E) Every energy transformation by a cell decreases the entropy of the universe.
Answer: D
8) You are confronted with a box of preserved grasshoppers of various species that are new to science and have not been described. Your assignment is to separate them into species. There is no accompanying information as to where or when they were collected. Which species concept will you have to use? A) biological B) phylogenetic C) ecological D) morphological
Answer: D
80) Which of the following is an example of hydrolysis? A) the reaction of two monosaccharides, forming a disaccharide with the release of water B) the synthesis of two amino acids, forming a peptide with the release of water C) the reaction of a fat, forming glycerol and fatty acids with the release of water D) the reaction of a fat, forming glycerol and fatty acids with the utilization of water E) the synthesis of a nucleotide from a phosphate, a pentose sugar, and a nitrogenous base with the production of a molecule of water
Answer: D
74) If the curve shifts to the left or to the right, there is no gene flow, and the population size consequently increases over successive generations, then which of these is (are) probably occurring? 1. immigration or emigration 2. directional selection 3. adaptation 4. genetic drift 5. disruptive selection A) 1 only B) 4 only C) 2 and 3 D) 4 and 5 E) 1, 2, and 3
Answer: C
75) The appearance of Pax-6 in all animals with eyes can be explained in multiple ways. Based on the information above, which explanation is most likely? A) Pax-6 in all of these animals is not homologous; it arose independently in many different animal phyla due to intense selective pressure favoring vision. B) The Pax-6 gene is really not ʺoneʺ gene. It is many different genes that, over evolutionary time and due to convergence, have come to have a similar nucleotide sequence and function. C) The Pax-6 gene was an innovation of an ancestral animal of the early Cambrian. Animals with eyes or eyespots are descendants of this ancestor. D) The perfectly designed Pax-6 gene appeared instantaneously in all animals created to have eyes or eyespots.
Answer: C
76) Of the following, which is the most current description of a gene? A) a unit of heredity that causes formation of a phenotypic characteristic B) a DNA subunit that codes for a single complete protein C) a DNA sequence that is expressed to form a functional product: either RNA or polypeptide D) a DNA—RNA sequence combination that results in an enzymatic product E) a discrete unit of hereditary information that consists of a sequence of amino acids
Answer: C
8) Organisms interact with their environments, exchanging matter and energy. For example, plant chloroplasts convert the energy of sunlight into A) the energy of motion. B) carbon dioxide and water. C) the potential energy of chemical bonds. D) oxygen. E) kinetic energy.
Answer: C
8) What is the hydroxide ion concentration of the lake described in question 7? A) 10-7 M B) 10-4 M C) 10-10 M D) 10-14 M E) 10 M
Answer: C
83) The incidence of cancer increases dramatically in older humans because A) the Ras protein is more likely to be hyperactive after age sixty. B) proteasomes become more active with age. C) as we age, normal cell division inhibitors cease to function. D) the longer we live, the more mutations we accumulate. E) tumor-suppressor genes are no longer able to repair damaged DNA.
Answer: D
8) Which of the following investigators was/were responsible for the following discovery? Chemicals from heat-killed S cells were purified. The chemicals were tested for the ability to transform live R cells. The transforming agent was found to be DNA. A) Frederick Griffith B) Alfred Hershey and Martha Chase C) Oswald Avery, Maclyn McCarty, and Colin MacLeod D) Erwin Chargaff E) Matthew Meselson and Franklin Stahl
Answer: C
8) Which of the following is an example of post - transcriptional control of gene expression? A) the addition of methyl groups to cytosine bases of DNA B) the binding of transcription factors to a promoter C) the removal of introns and splicing together of exons D) gene amplification during a stage in development E) the folding of DNA to form heterochromatin
Answer: C
8) microfilament of the cytoskeleton
Answer: C
83) Which of the following store and transmit hereditary information? A) carbohydrates B) lipids C) proteins D) nucleic acids
Answer: D
80) One function of both alcohol fermentation and lactic acid fermentation is to A) reduce NAD+ to NADH. B) reduce FAD+ to FADH2 . C) oxidize NADH to NAD+ . D) reduce FADH2 to FAD+ . E) none of the above
Answer: C
82) Tumor suppressor genes A) are frequently overexpressed in cancerous cells. B) are cancer-causing genes introduced into cells by viruses. C) can encode proteins that promote DNA repair or cell -cell adhesion. D) often encode proteins that stimulate the cell cycle. E) all of the above
Answer: C
84) Enzymes are A) carbohydrates. B) lipids. C) proteins. D) nucleic acids.
Answer: C
86) When muscle cells undergo anaerobic respiration, they become fatigued and painful. This is now known to be caused by A) buildup of pyruvate. B) buildup of lactate. C) increase in sodium ions. D) increase in potassium ions. E) increase in ethanol.
Answer: D
84) Muscle cells, when an individual is exercising heavily and when the muscle becomes oxygen deprived, convert pyruvate to lactate. What happens to the lactate in skeletal muscle cells? A) It is converted to NAD+ . B) It produces CO2 and water. C) It is taken to the liver and converted back to pyruvate. D) It reduces FADH2 to FAD+ . E) It is converted to alcohol.
Answer: C
9) What did Engelmann conclude about the congregation of bacteria in the red and blue areas? A) Bacteria released excess carbon dioxide in these areas. B) Bacteria congregated in these areas due to an increase in the temperature of the red and blue light. C) Bacteria congregated in these areas because these areas had the most oxygen being released. D) Bacteria are attracted to red and blue light and thus these wavelengths are more reactive than other wavelengths. E) Bacteria congregated in these areas due to an increase in the temperature caused by an increase in photosynthesis.
Answer: C
9) Which statement about the beak size of finches on the island of Daphne Major during prolonged drought is true? A) Each bird evolved a deeper, stronger beak as the drought persisted. B) Each bird developed a deeper, stronger beak as the drought persisted. C) Each birdʹs survival was strongly influenced by the depth and strength of its beak as the drought persisted. D) Each bird that survived the drought produced only offspring with deeper, stronger beaks than seen in the previous generation. E) The frequency of the strong-beak alleles increased in each bird as the drought persisted.
Answer: C
9) Why is it preferable to use large computers and databases in searching for individual genes, rather than testing each sequence for possible function? A) Testing for function would require too many cells. B) Testing for function would require knowing the species, its life stage, and its phylogeny. C) Testing for function would require knowing where a particular gene starts and ends and how it is regulated. D) Use of computer databases is intellectually less rigorous. E) The computer data can be sent to more labs.
Answer: C
91) One of the human leukemias, called CML (chronic myelogenous leukemia) is associated with a chromosomal translocation between chromosomes 9 and 22 in somatic cells of bone marrow. Which of the following allows CML to provide further evidence of this multi -step nature of cancer? A) CML usually occurs in more elderly persons (late age of onset). B) The resulting chromosome 22 is abnormally short; it is then known as the Philadelphia chromosome. C) The translocation requires breaks in both chromosomes 9 and 22, followed by fusion between the reciprocal pieces. D) CML involves a proto-oncogene known as abl. E) CML can usually be treated by chemotherapy.
Answer: C
93) Where do the catabolic products of fatty acid breakdown enter into the citric acid cycle? A) pyruvate B) malate or fumarate C) acetyl CoA D) α-ketoglutarate E) succinyl CoA
Answer: C
93) Which of the following molecules could be joined together by a peptide bond as a result of a dehydration reaction? A) 2 and 3 B) 3 and 7 C) 7 and 8 D) 8 and 9 E) 12 and 13
Answer: C
88) One hereditary disease in humans, called xeroderma pigmentosum (XP), makes homozygous individuals exceptionally susceptible to UV - induced mutation damage in the cells of exposed tissue, especially skin. Without extraordinary avoidance of sunlight exposure, patients soon succumb to numerous skin cancers. Which of the following best describes this phenomenon? A) inherited cancer taking a few years to be expressed B) embryonic or fetal cancer C) inherited predisposition to mutation D) inherited inability to repair UV- induced mutation E) susceptibility to chemical carcinogens
Answer: D
E) Each of the illustrations in the other answer choices depicts a structural isomer of the compound with molecular formula C 6H14.
Answer: C
1) A bacterium is infected with an experimentally constructed bacteriophage composed of the T2 phage protein coat and T4 phage DNA. The new phages produced would have A) T2 protein and T4 DNA. B) T2 protein and T2 DNA. C) a mixture of the DNA and proteins of both phages. D) T4 protein and T4 DNA. E) T4 protein and T2 DNA.
Answer: D
1) A fruit fly population has a gene with two alleles, A1 and A2. Tests show that 70% of the gametes produced in the population contain the A1 allele. If the population is in Hardy-Weinberg equilibrium, what proportion of the flies carry both A1 and A2? A) 0.7 B) 0.49 C) 0.21 D) 0.42 E) 0.09
Answer: D
1) About 25 of the 92 natural elements are known to be essential to life. Which four of these 25 elements make up approximately 96% of living matter? A) carbon, sodium, chlorine, nitrogen B) carbon, sulfur, phosphorus, hydrogen C) oxygen, hydrogen, calcium, sodium D) carbon, hydrogen, nitrogen, oxygen E) carbon, oxygen, sulfur, calcium
Answer: D
1) If a particular operon encodes enzymes for making an essential amino acid and is regulated like the trp operon, then the A) amino acid inactivates the repressor. B) enzymes produced are called inducible enzymes. C) repressor is active in the absence of the amino acid. D) amino acid acts as a corepressor. E) amino acid turns on transcription of the operon.
Answer: D
1) Many mammals control their body temperature by sweating. Which property of water is most directly responsible for the ability of sweat to lower body temperature? A) waterʹs change in density when it condenses B) waterʹs ability to dissolve molecules in the air C) the release of heat by the formation of hydrogen bonds D) the absorption of heat by the breaking of hydrogen bonds E) waterʹs high surface tension
Answer: D
1) Pea plants were particularly well suited for use in Mendelʹs breeding experiments for all of the following reasons except that A) peas show easily observed variations in a number of characters, such as pea shape and flower color. B) it is possible to control matings between different pea plants. C) it is possible to obtain large numbers of progeny from any given cross. D) peas have an unusually long generation time. E) many of the observable characters that vary in pea plants are controlled by single genes.
Answer: D
1) The light reactions of photosynthesis supply the Calvin cycle with A) light energy. B) CO2 and ATP. C) H2O and NADPH. D) ATP and NADPH. E) sugar and O2 .
Answer: D
1) What characteristics of electron microscopes make them most useful for studying viruses? A) high energy electrons with high penetrance B) requirement that specimens be viewed in a vacuum C) necessity for specimens to be dry and fixed D) shorter wavelengths providing higher resolution E) use of magnetic fields to focus electrons
Answer: D
1) Which term includes all others in the list? A) monosaccharide B) disaccharide C) starch D) carbohydrate E) polysaccharide
Answer: D
10) An outcome of this experiment was to help determine A) the relationship between heterotrophic and autotrophic organisms. B) the relationship between wavelengths of light and the rate of aerobic respiration. C) the relationship between wavelengths of light and the amount of heat released. D) the relationship between wavelengths of light and the oxygen released during photosynthesis. E) the relationship between the concentration of carbon dioxide and the rate of photosynthesis.
Answer: D
10) The human X and Y chromosomes A) are both present in every somatic cell of males and females alike. B) are of approximately equal size and number of genes. C) are almost entirely homologous, despite their different names. D) include genes that determine an individualʹs sex. E) include only genes that govern sex determination.
Answer: D
10) Which of the following investigators was/were responsible for the following discovery? In DNA from any species, the amount of adenine equals the amount of thymine, and the amount of guanine equals the amount of cytosine. A) Frederick Griffith B) Alfred Hershey and Martha Chase C) Oswald Avery, Maclyn McCarty, and Colin MacLeod D) Erwin Chargaff E) Matthew Meselson and Franklin Stahl
Answer: D
11) How does active CAP induce expression of the genes of the lactose operon? A) It terminates production of repressor molecules. B) It degrades the substrate allolactose. C) It stimulates splicing of the encoded genes. D) It stimulates the binding of RNA polymerase to the promoter. E) It binds steroid hormones and controls translation.
Answer: D
11) How many electron pairs does carbon share in order to complete its valence shell? A) 1 B) 2 C) 3 D) 4 E) 8
Answer: D
11) Which is the longest of the mitotic stages? A) telophase B) anaphase C) prometaphase D) metaphase E) prophase
Answer: D
11) Which of the following is an example of potential rather than kinetic energy? A) a boy mowing grass B) water rushing over Niagara Falls C) a firefly using light flashes to attract a mate D) a food molecule made up of energy-rich macromolecules E) an insect foraging for food
Answer: D
11) Which type of bond must be broken for water to vaporize? A) ionic bonds B) nonpolar covalent bonds C) polar covalent bonds D) hydrogen bonds E) covalent bonds
Answer: D
9) Determine the sequence of genes along a chromosome based on the following recombination frequencies: A—B, 8 map units; A—C, 28 map units; A—D, 25 map units; B —C , 20 map units; B—D, 33 map units.
Answer: D—A—B—C
1) Who was/were the first to propose that cell membranes are phospholipid bilayers? A) H. Davson and J. Danielli B) I. Langmuir C) C. Overton D) S. Singer and G. Nicolson E) E. Gorter and F. Grendel
Answer: E
10) Dozens of potato varieties exist, differing from each other in potato- tuber size, skin color, flesh color, and shape. One might construct a classification of potatoes based on these morphological traits. Which of these criticisms of such a classification scheme is most likely to come from an adherent of the phylocode method of classification? A) Flesh color, rather than skin color, is a valid trait to use for classification because it is less susceptible to change with the age of the tuber. B) Flower color is a better classification criterion, because below-ground tubers can be influenced by minerals in the soil as much as by their genes. C) A more useful classification would codify potatoes based on the texture and flavor of their flesh, because this is what humans are concerned with. D) The most accurate phylogenetic code is that of Linnaeus. Classify potatoes based on Linnaean principles; not according to their color. E) The only biologically valid classification of potato varieties is one that accurately reflects their genetic and evolutionary relatedness.
Answer: E
10) The dynamics of any ecosystem include the following major processes: A) the flow of energy from sunlight to producers B) the flow of energy from sunlight to producers and then to consumers C) the recycling of chemical nutrients D) the flow of energy to producers and the recycling of nutrients E) the flow of energy from sunlight to producers and then to consumers, and the recycling of chemical nutrients.
Answer: E
10) When biological membranes are frozen and then fractured, they tend to break along the middle of the bilayer. The best explanation for this is that A) the integral membrane proteins are not strong enough to hold the bilayer together. B) water that is present in the middle of the bilayer freezes and is easily fractured. C) hydrophilic interactions between the opposite membrane surfaces are destroyed on freezing. D) the carbon-carbon bonds of the phospholipid tails are easily broken. E) the hydrophobic interactions that hold the membrane together are weakest at this point.
Answer: E
10) Which pair would have been likely to agree that strata such as those depicted here were deposited gradually over long periods of time by subtle mechanisms that are still at work? A) Cuvier and Aristotle B) Cuvier and Lamarck C) Lyell and Linnaeus D) Aristotle and Hutton E) Hutton and Lyell
Answer: E
10) Which term describes centrioles beginning to move apart in animal cells? A) telophase B) anaphase C) prometaphase D) metaphase E) prophase
Answer: E
100) Which of the following statements is false? A) 1 and 4 could be joined together by a glycosidic linkage to form a disaccharide. B) 9 and 10 could be joined together by ester bonds to form a triacylglycerol. C) 2 and 7 could be joined together to form a short peptide. D) 2, 7, and 8 could be joined together to form a short peptide. E) 14 and 15 could be joined together to form a polypeptide.
Answer: E
11) A possible sequence of nucleotides in the template strand of DNA that would code for the polypeptide sequence phe- leu- ile-val would be A) 5ʹ TTG-CTA-CAG-TAG 3ʹ. B) 3ʹ AAC-GAC-GUC-AUA 5ʹ. C) 5ʹ AUG-CTG-CAG-TAT 3ʹ. D) 3ʹ AAA-AAT-ATA-ACA 5ʹ. E) 3ʹ AAA-GAA-TAA-CAA 5ʹ.
Answer: E
11) All of the following are part of a prokaryotic cell except A) DNA. B) a cell wall. C) a plasma membrane. D) ribosomes. E) an endoplasmic reticulum.
Answer: E
11) An atom with an atomic number of 9 and a mass number of 19 would have an atomic mass of approximately A) 9 daltons. B) 9 grams. C) 10 daltons. D) 20 grams. E) 19 daltons.
Answer: E
12) Which of the boxes marked 1 -4 correspond to plants with dark leaves? A) 1 only B) 1 and 2 C) 2 and 3 D) 4 only E) 1, 2, and 3
Answer: E
13) A mycoplasma is an organism with a diameter between 0.1 and 1.0 μm. What does its size tell you about how it might be classified? A) It must be a single celled protist. B) It must be a single celled fungus. C) It could be almost any typical bacterium. D) It could be a typical virus. E) It could be a very small bacterium.
Answer: E
13) Red-green color blindness is a sex- linked recessive trait in humans. Two people with normal color vision have a color-blind son. What are the genotypes of the parents? A) XcXc and XcY B) XcXc and XCY C) XCXC and XcY D) XCXC and XCY E) XCXc and XCY
Answer: E
13) The higher the proportion of loci that are ʺfixedʺ in a population, the lower is that populationʹs A) nucleotide variability. B) genetic polyploidy. C) average heterozygosity. D) A, B, and C E) A and C only
Answer: E
13) Which of the following statements best describes the carbon atoms present in all organic molecules? A) They were incorporated into organic molecules by plants. B) They were processed into sugars through photosynthesis. C) They are ultimately derived from carbon dioxide. D) Only A and C are correct. E) A, B, and C are correct.
Answer: E
14) A molecule with the chemical formula C6H12O6 is probably a A) carbohydrate. B) lipid. C) monosaccharide D) A and B only. E) A, B, and C.
Answer: E
14) Cinnabar eyes is a sex- linked recessive characteristic in fruit flies. If a female having cinnabar eyes is crossed with a wild- type male, what percentage of the F 1 males will have cinnabar eyes? A) 0% B) 25% C) 50% D) 75% E) 100%
Answer: E
14) What is the sequence of a peptide based on the following mRNA sequence? 5ʹ . . . UUUUCUUAUUGUCUU 3ʹ A) leu-cys- tyr-ser-phe B) cyc-phe- tyr-cys- leu C) phe- leu- ile-met-val D) leu-pro-asp- lys-gly E) phe-ser- tyr-cys- leu
Answer: E
14) Which of the following is a false statement regarding deoxyribonucleic acid (DNA)? A) Each deoxyribonucleic acid molecule is composed of two long chains of nucleotides arranged in a double helix. B) Genes are composed of deoxyribonucleic acid. C) DNA is composed of chemical building blocks called nucleotides. D) DNA is a code for the sequence of amino acids in a protein. E) DNA is an enzyme that puts together amino acids to make a protein.
Answer: E
15) In a hypothetical populationʹs gene pool, an autosomal gene, which had previously been fixed, undergoes a mutation that introduces a new allele, one inherited according to incomplete dominance. Natural selection then causes stabilizing selection at this locus. Consequently, what should happen over the course of many generations? A) The proportions of both types of homozygote should decrease. B) The proportion of the population that is heterozygous at this locus should remain constant. C) The populationʹs average heterozygosity should increase. D) Both (A)and (B) E) Both (A)and (C)
Answer: E
15) What is the change in free energy of a system at chemical equilibrium? A) slightly increasing B) greatly increasing C) slightly decreasing D) greatly decreasing E) no net change
Answer: E
15) Yeast artificial chromosomes contain which of the following elements? A) centromere only B) telomeres only C) origin of replication only D) centromeres and telomeres only E) centromere, telomeres, and an origin of replication
Answer: E
16) Which of the following about the law of segregation is false? A) It states that each of two alleles for a given trait segregate into different gametes. B) It can be explained by the segregation of homologous chromosomes during meiosis. C) It can account for the 3:1 ratio seen in the F2 generation of Mendelʹs crosses. D) It can be used to predict the likelihood of transmission of certain genetic diseases within families. E) It is a method that can be used to determine the number of chromosomes in a plant.
Answer: E
16) Which of the following descriptors is true of the molecule shown in Figure 5.1? A) hexose B) fructose C) glucose D) A and B only E) A and C only
Answer: E
17) A researcher needs to clone a sequence of part of a eukaryotic genome in order to express the sequence and to modify the polypeptide product. She would be able to satisfy these requirements by using which of the following vectors? A) a bacterial plasmid B) BAC to accommodate the size of the sequence C) a modified bacteriophage D) a human chromosome E) a YAC with appropriate cellular enzymes
Answer: E
17) Natural selection is based on all of the following except A) genetic variation exists within populations. B) the best-adapted individuals tend to leave the most offspring. C) individuals who survive longer tend to leave more offspring than those who die young. D) populations tend to produce more individuals than the environment can support. E) individuals adapt to their environments and, thereby, evolve.
Answer: E
17) One mole (mol) of a substance is A) 6.02 × 1023 molecules of the substance. B) 1 g of the substance dissolved in 1 L of solution. C) the largest amount of the substance that can be dissolved in 1 L of solution. D) the molecular mass of the substance expressed in grams. E) A and D only
Answer: E
17) Recent evidence shows that individual chromosomes occupy fairly defined territories within the nucleus. Given the structure and location of the following parts of the nucleus, which would be more probably involved in chromosome location? A) nuclear pores B) the nucleolus C) the outer lipid bilayer D) the nuclear lamina E) the nuclear matrix
Answer: E
17) The importance of computers and of computer software to modern cladistics is most closely linked to advances in A) light microscopy. B) radiometric dating. C) fossil discovery techniques. D) Linnaean classification. E) molecular genetics.
Answer: E
17) Which of the events listed below occur in the light reactions of photosynthesis? A) NADP is produced. B) NADPH is reduced to NADP+ . C) carbon dioxide is incorporated into PGA. D) ATP is phosphorylated to yield ADP. E) light is absorbed and funneled to reaction -center chlorophyll a.
Answer: E
18) How many molecules of glucose (C 6H2O6 molecular mass =180 daltons) would be present in one mole of glucose? A) 24 B) 342 C) 23 × 1014 D) 180 × 1014 E) 6.02 × 1023
Answer: E
18) If she moves the repressor gene (lac I), along with its promoter, to a position at some several thousand base pairs away from its normal position, which will you expect to occur? A) The repressor will no longer be made. B) The repressor will no longer bind to the operator. C) The repressor will no longer bind to the inducer. D) The lac operon will be expressed continuously. E) The lac operon will function normally.
Answer: E
18) If the half- life of carbon-14 is about 5,730 years, then a fossil that has one -sixteenth the normal proportion of carbon-14 to carbon-12 should be about how many years old? A) 1,400 B) 2,800 C) 11,200 D) 16,800 E) 22,400
Answer: E
18) Mendel was able to draw his ideas of segregation and independent assortment because of the influence of which of the following? A) His reading and discussion of Darwinʹs Origin of Species B) The understanding of particulate inheritance he learned from renowned scientists of his time C) His discussions of heredity with his colleagues at major universities D) His reading of the scientific literature current in the field E) His experiments with the breeding of plants such as peas
Answer: E
18) Most molecular biologists think that viruses originated from fragments of cellular nucleic acid. Which of the following observations supports this theory? A) Viruses contain either DNA or RNA. B) Viruses are enclosed in protein capsids rather than plasma membranes. C) Viruses can reproduce only inside host cells. D) Viruses can infect both prokaryotic and eukaryotic cells. E) Viral genomes are usually more similar to the genome of the host cell than to the genomes of viruses that infect other cell types.
Answer: E
18) Of the following functions, which is most important for the glycoproteins and glycolipids of animal cell membranes? A) facilitated diffusion of molecules down their concentration gradients B) active transport of molecules against their concentration gradients C) maintaining the integrity of a fluid mosaic membrane D) maintaining membrane fluidity at low temperatures E) a cellʹs ability to distinguish one type of neighboring cell from another
Answer: E
19) How many molecules of glycerol (C3H8O3 ) would be present in 1 L of a 1 M glycerol solution? A) 1 B) 14 C) 92 D) 1 × 107 E) 6.02 × 1023
Answer: E
19) If glucose is available in the environment of E. coli, the cell responds with very low concentration of cAMP. When the cAMP increases in concentration, it binds to CAP. Which of the following would you expect would then be a measurable effect? A) decreased concentration of the lac enzymes B) increased concentration of the trp enzymes C) decreased binding of the RNA polymerase to sugar metabolism -related promoters D) decreased concentration of alternative sugars in the cell E) increased concentrations of sugars such as arabinose in the cell
Answer: E
19) What is the most probable explanation for the continued presence of pseudogenes in a genome such as our own? A) They are genes that had a function at one time, but that have lost their function because they have been translocated to a new location. B) They are genes that have accumulated mutations to such a degree that they would code for different functional products if activated. C) They are duplicates or near duplicates of functional genes but cannot function because they would provide inappropriate dosage of protein products. D) They are genes with significant inverted sequences. E) They are genes that are not expressed, even though they have nearly identical sequences to expressed genes.
Answer: E
19) Which example below will most likely guarantee that two closely related species will persist only as distinct biological species? A) colonization of new habitats B) convergent evolution C) hybridization D) geographic isolation from one another E) reproductive isolation from one another
Answer: E
2) The role of a metabolite that controls a repressible operon is to A) bind to the promoter region and decrease the affinity of RNA polymerase for the promoter. B) bind to the operator region and block the attachment of RNA polymerase to the promoter. C) increase the production of inactive repressor proteins. D) bind to the repressor protein and inactivate it. E) bind to the repressor protein and activate it.
Answer: E
20) HIV has 9 genes in its RNA genome. Every HIV particle contains two RNA molecules, each molecule containing all 9 genes. If, for some reason, the two RNA molecules within a single HIV particle do not have identical sequences, then which of these terms can be applied due to the existence of the non- identical regions? A) homozygous B) gene variability C) nucleotide variability D) average heterozygosity E) all except A
Answer: E
20) The two molecules shown in Figure 4.3 are best described as A) enantiomers. B) radioactive isotopes. C) structural isomers. D) nonisotopic isomers. E) geometric isomers.
Answer: E
21) A biologist studied a population of squirrels for 15 years. During that time, the population was never fewer than 30 squirrels and never more than 45. Her data showed that over half of the squirrels born did not survive to reproduce, because of competition for food and predation. In a single generation, 90% of the squirrels that were born lived to reproduce, and the population increased to 80. Which inference(s) about this population might be true? A) The amount of available food may have increased. B) The number of predators may have decreased. C) The squirrels of subsequent generations should show greater levels of genetic variation than previous generations, because squirrels that would not have survived in the past will now survive. D) A and B only E) A, B, and C
Answer: E
21) From its atomic number of 15, it is possible to predict that the phosphorus atom has A) 15 neutrons. B) 15 protons. C) 15 electrons. D) 8 electrons in its outermost electron shell. E) B and C only
Answer: E
21) If a cell has 8 chromosomes at metaphase of mitosis, how many chromosomes will it have during anaphase? A) 1 B) 2 C) 4 D) 8 E) 16
Answer: E
21) If two genes from one RNA molecule become detached and then, as a unit, get attached to one end of the other RNA molecule within a single HIV particle, which of these is true? A) There are now fewer genes within the viral particle. B) There are now more genes within the viral particle. C) A point substitution mutation has occurred in the retroviral genome. D) The retroviral equivalent of crossing-over has occurred, no doubt resulting in a heightened positive effect. E) One of the RNA molecules has experienced gene duplication as the result of translocation.
Answer: E
21) In a hypothetical situation, a certain species of flea feeds only on pronghorn antelopes. In rangelands of the western United States, pronghorns and cattle often associate with one another. If some of these fleas develop a strong preference, instead, for cattle blood and mate only with fleas that, likewise, prefer cattle blood, then over time which of these should occur, if the host mammal can be considered as the fleasʹ habitat? 1. reproductive isolation 2. sympatric speciation 3. habitat isolation 4. prezygotic barriers A) 1 only B) 2 and 3 C) 1, 2, and 3 D) 2, 3, and 4 E) 1 through 4
Answer: E
21) The Golgi apparatus has a polarity or sidedness to its structure and function. Which of the following statements correctly describes this polarity? A) Transport vesicles fuse with one side of the Golgi and leave from the opposite side. B) Proteins in the membrane of the Golgi may be sorted and modified as they move from one side of the Golgi to the other. C) Lipids in the membrane of the Golgi may be sorted and modified as they move from one side of the Golgi to the other. D) Soluble proteins in the cisternae (interior) of the Golgi may be sorted and modified as they move from one side of the Golgi to the other. E) All of the above correctly describe polar characteristics of the Golgi function.
Answer: E
21) The coupled G protein most likely interacts with this receptor A) at the NH3 end B) at the COO- end C) along the exterior margin D) along the interior margin E) at the loop between H5 and H6
Answer: E
21) The molecular mass of glucose is 180 g. Which of the following procedures should you carry out to make a 1 M solution of glucose? A) Dissolve 1 g of glucose in 1 L of water. B) Dissolve 180 g of glucose in 1 L of water. C) Dissolve 180 g of glucose in 100 g of water. D) Dissolve 180 mg (milligrams) of glucose in 1 L of water. E) Dissolve 180 g of glucose in water, and then add more water until the total volume of the solution is 1 L.
Answer: E
22) Suppose you are provided with an actively dividing culture of E. coli bacteria to which radioactive thymine has been added. What would happen if a cell replicates once in the presence of this radioactive base? A) One of the daughter cells, but not the other, would have radioactive DNA. B) Neither of the two daughter cells would be radioactive. C) All four bases of the DNA would be radioactive. D) Radioactive thymine would pair with nonradioactive guanine. E) DNA in both daughter cells would be radioactive.
Answer: E
22) The karyotype of one species of primate has 48 chromosomes. In a particular female, cell division goes awry and she produces one of her eggs with an extra chromosome (25). The most probable source of this error would be a mistake in which of the following? A) Mitosis in her ovary B) Metaphase I of one meiotic event C) Telophase II of one meiotic event D) Telophase I of one meiotic event E) Either anaphase I or II
Answer: E
22) To observe natural selectionʹs effects on a population, which of these must be true? A) One must observe more than one generation of the population. B) The population must contain genetic variation. C) Members of the population must increase or decrease the use of some portion of their anatomy. D) A and C only E) A and B only
Answer: E
23) A given organism has 46 chromosomes in its karyotype. We can therefore conclude which of the following? A) It must be human. B) It must be a primate. C) It must be an animal. D) It must be sexually reproducing. E) Its gametes must have 23 chromosomes.
Answer: E
23) Several of the different globin genes are expressed in humans, but at different times in development. What mechanism could allow for this? A) exon shuffling B) intron activation C) pseudogene activation D) differential translation of mRNAs E) differential gene regulation over time
Answer: E
23) When 10,000 molecules of ATP are hydrolyzed to ADP and Pi in a test tube, about twice as much heat is liberated as when a cell hydrolyzes the same amount of ATP. Which of the following is the best explanation for this observation? A) Cells are open systems, but a test tube is a closed system. B) Cells are less efficient at heat production than nonliving systems. C) The hydrolysis of ATP in a cell produces different chemical products than does the reaction in a test tube. D) The reaction in cells must be catalyzed by enzymes, but the reaction in a test tube does not need enzymes. E) Reactant and product concentrations are not the same
Answer: E
24) Earthʹs current magnetic field is the same as it had been when which sea - floor areas solidified? I. area B II. area C III. area D IV. area E A) I only B) II only C) I and II D) I and III E) II and IV
Answer: E
24) In a cross AaBbCc × AaBbCc, what is the probability of producing the genotype AABBCC? A) 1/4 B) 1/8 C) 1/16 D) 1/32 E) 1/64
Answer: E
24) The formation of a cell plate is beginning across the middle of a cell and nuclei are re- forming at opposite ends of the cell. What kind of cell is this? A) an animal cell in metaphase B) an animal cell in telophase C) an animal cell undergoing cytokinesis D) a plant cell in metaphase E) a plant cell undergoing cytokinesis
Answer: E
25) If this evolutionary tree is an accurate depiction of relatedness, then which of the following should be correct? 1. The entire tree is based on maximum parsimony. 2. If all species depicted here make up a taxon, this taxon is monophyletic. 3. The last common ancestor of species B and C occurred more recently than the last common ancestor of species D and E. 4. Species A is the direct ancestor of both species B and species C. 5. The species present at position 3 is ancestral to C, D, and E. A) 2 and 5 B) 1 and 3 C) 3 and 4 D) 2, 3, and 4 E) 1, 2, and 3
Answer: E
25) Prokaryotes are classified as belonging to two different domains. What are the domains? A) Bacteria and Eukarya B) Archaea and Monera C) Eukarya and Monera D) Bacteria and Protista E) Bacteria and Archaea
Answer: E
25) Which of the following i s used to make complementary DNA (cDNA) from RNA? A) restriction enzymes B) gene cloning C) DNA ligase D) gel electrophoresis E) reverse transcriptase
Answer: E
26) A 0.1% frequency of recombination is observed A) only in sex chromosomes. B) only on genetic maps of viral chromosomes. C) on unlinked chromosomes. D) in any two genes on different chromosomes. E) in genes located very close to one another on the same chromosome.
Answer: E
26) These results indicate which of the following? A) Brown is dominant to black. B) Black is dominant to brown and to yellow. C) Yellow is dominant to black. D) There is incomplete dominance. E) Epistasis is involved.
Answer: E
26) Which drawing depicts an atom that is inert or chemically unreactive?
Answer: E
27) In eukaryotes, transcription is generally associated with A) euchromatin only. B) heterochromatin only. C) very tightly packed DNA only. D) highly methylated DNA only. E) both euchromatin and histone acetylation.
Answer: E
27) Sutherland discovered that epinephrine A) signals bypass the plasma membrane of cells. B) lowers blood glucose by binding to liver cells. C) interacts with insulin inside muscle cells. D) interacts directly with glycogen phosphorylase. E) elevates the cytosolic concentration of cyclic AMP.
Answer: E
27) Two species that belong to the same genus must also belong to the same A) kingdom. B) phylum. C) class. D) order. E) all of the above
Answer: E
28) During which phases of mitosis are chromosomes composed of two chromatids? A) from interphase through anaphase B) from G1 of interphase through metaphase C) from metaphase through telophase D) from anaphase through telophase E) from G2 of interphase through metaphase
Answer: E
29) Letʹs say that a hypothetical submersible robot was used to collect samples of sedimentary rock from the sea floor along the section illustrated. The robot moved back and forth along the transect, collecting first from site A, then site III, then site B, then site II, and lastly site D. Assuming that sedimentation has occurred at a constant rate along the transect over the past million years, rearrange the sites mentioned above on the basis of the thickness of the sediments overlying the igneous rock, from thickest to thinnest. A) A, B, II, D, III B) I, II, III C) III, II, D, B, A D) III, A, II, B, D E) III, D, II, B, A
Answer: E
29) The molecule shown in Figure 5.3 is a A) polysaccharide. B) polypeptide. C) saturated fatty acid. D) triacylglycerol. E) unsaturated fatty acid.
Answer: E
29) Which is the best description of a carbonyl group? A) an oxygen joined to a carbon by a single covalent bond B) a nitrogen and two hydrogens joined to a carbon by covalent bonds C) a carbon joined to two hydrogens by single covalent bonds D) a sulfur and a hydrogen joined to a carbon by covalent bonds E) a carbon atom joined to an oxygen by a double covalent bond
Answer: E
3) Asexual reproduction and sexual reproduction differ in all but which of the following ways? A) Individuals reproducing asexually transmit 100% of their genes to their progeny, whereas individuals reproducing sexually transmit only 50%. B) Asexual reproduction produces offspring that are genetically identical to the parents, whereas sexual reproduction gives rise to genetically distinct offspring. C) Asexual reproduction involves a single parent, whereas sexual reproduction involves two. D) Asexual reproduction requires only mitosis, whereas sexual reproduction always involves meiosis. E) Asexual reproduction is utilized only by fungi and protists, whereas sexual reproduction is utilized only by plants and animals.
Answer: E
3) Natural selection changes allele frequencies in populations because some __________ survive and reproduce more successfully than others. A) alleles B) loci C) gene pools D) species E) individuals
Answer: E
3) The experimental approach taken in current biological investigations presumes that A) simple organic compounds can be synthesized in the laboratory from inorganic precursors, but complex organic compounds like carbohydrates and proteins can only be synthesized by living organisms. B) a life force ultimately controls the activities of living organisms and this life force cannot be studied by physical or chemical methods. C) although a life force, or vitalism, exists in living organisms, this life force cannot be studied by physical or chemical methods. D) living organisms are composed of the same elements present in nonliving things, plus a few special trace elements found only in living organisms or their products. E) living organisms can be understood in terms of the same physical and chemical laws that can be used to explain all natural phenomena.
Answer: E
3) The tryptophan operon is a repressible operon that is A) permanently turned on. B) turned on only when tryptophan is present in the growth medium. C) turned off only when glucose is present in the growth medium. D) turned on only when glucose is present in the growth medium. E) turned off whenever tryptophan is added to the growth medium.
Answer: E
3) What are the products of the light reactions that are subsequently used by the Calvin cycle? A) oxygen and carbon dioxide B) carbon dioxide and RuBP C) water and carbon D) electrons and photons E) ATP and NADPH
Answer: E
3) When electrons move closer to a more electronegative atom, what happens? A) Energy is released. B) Energy is consumed. C) The more electronegative atom is reduced. D) The more electronegative atom is oxidized. E) A and C are correct.
Answer: E
30) What must be the difference (if any) between the structure of ATP and the structure of the precursor of the A nucleotide in DNA and RNA? A) The sugar molecule is different. B) The nitrogen-containing base is different. C) The number of phosphates is three instead of one. D) The number of phosphates is three instead of two. E) There is no difference.
Answer: E
30) Which of the following describes cell communication systems? A) Cell signaling evolved more recently than systems such as the immune system of vertebrates. B) Communicating cells are usually close together. C) Most signal receptors are bound to the outer membrane of the nuclear envelope. D) Lipid phosphorylation is a major mechanism of signal transduction. E) In response to a signal, the cell may alter activities by changes in cytosol activity or in transcription of RNA.
Answer: E
31) Centromeres of sister chromatids disjoin and chromatids separate. A) II B) III C) IV D) V E) VII
Answer: E
31) How many electrons does phosphorus have in its valence shell? A) 1 B) 2 C) 3 D) 4 E) 5
Answer: E
31) The hydrogenation of vegetable oil results in which of the following? A) saturated fats and unsaturated fats with trans double bonds B) an increased contribution to artherosclerosis C) the oil (fat) being a solid at room temperature D) A and C only E) A, B, and C
Answer: E
31) Which of the following two genes are closest on a genetic map of Drosophila? A) b and vg B) vg and cn C) rb and cn D) cn and b E) b and rb
Answer: E
32) Genes D and F could be A) located on different chromosomes. B) located very near to each other on the same chromosome. C) located far from each other on the same chromosome. D) Both A and B E) Both A and C
Answer: E
32) The DNA of telomeres has been found to be highly conserved throughout the evolution of eukaryotes. What does this most probably reflect? A) the inactivity of this DNA B) the low frequency of mutations occurring in this DNA C) that new evolution of telomeres continues D) that mutations in telomeres are relatively advantageous E) that the critical function of telomeres must be maintained
Answer: E
32) Which of the following ionizes completely in solution and is considered to be a strong base (alkali)? A) NaCl B) HCl C) NH3 D) H2CO3 E) NaOH
Answer: E
32) Which of the following is (are) true of natural selection? A) requires genetic variation B) results in descent with modification C) involves differential reproductive success D) B and C only E) A, B, and C
Answer: E
32) Which of the following series best reflects what we know about how the flu virus moves between species? A) An avian flu virus undergoes several mutations and rearrangements such that it is able to be transmitted to other birds and then to humans. B) The flu virus in a pig is mutated and replicated in alternate arrangements so that humans who eat the pig products can be infected. C) A flu virus from a human epidemic or pandemic infects birds; the birds replicate the virus differently and then pass it back to humans. D) An influenza virus gains new sequences of DNA from another virus, such as a herpesvirus; this enables it to be transmitted to a human host. E) An animal such as a pig is infected with more than one virus, genetic recombination occurs, the new virus mutates and is passed to a new species such as a bird, the virus mutates and can be transmitted to humans.
Answer: E
32) Which of the following would be inhibited by a drug that specifically blocks the addition of phosphate groups to proteins? A) G-protein- linked receptor signaling B) ligand-gated ion channel signaling C) adenylyl cyclase activity D) phosphatase activity E) receptor tyrosine kinase activity
Answer: E
32) You sample a population of butterflies and find that 42% are heterozygous at a particular locus. What should be the frequency of the recessive allele in this population? A) 0.09 B) 0.30 C) 0.49 D) 0.70 E) Allele frequency cannot be determined from this information.
Answer: E
33) During cellular respiration, acetyl CoA accumulates in which location? A) cytosol B) mitochondrial outer membrane C) mitochondrial inner membrane D) mitochondrial intermembrane space E) mitochondrial matrix
Answer: E
33) The frequency of crossing over between any two linked genes will be which of the following? A) Higher if they are recessive B) Dependent on how many alleles there are C) Determined by their relative dominance D) The same as if they were not linked E) Proportional to the distance between them
Answer: E
33) What is the frequency of the B allele? A) 0.001 B) 0.002 C) 0.100 D) 0.400 E) 0.600
Answer: E
33) Which of the following contains enzymes that transfer hydrogen from various substrates to oxygen? A) lysosome B) vacuole C) mitochondrion D) Golgi apparatus E) peroxisome
Answer: E
33) Which of the following is the most probable fate of a newly emerging virus that causes high mortality in its host? A) It is able to spread to a large number of new hosts quickly because the new hosts have no immunological memory of them. B) The new virus replicates quickly and undergoes rapid adaptation to a series of divergent hosts. C) A change in environmental conditions such as weather patterns quickly forces the new virus to invade new areas. D) Sporadic outbreaks will be followed almost immediately by a widespread pandemic. E) The newly emerging virus will die out rather quickly or will mutate to be far less lethal.
Answer: E
33) Which of the following statements provides the strongest evidence that prokaryotes evolved before eukaryotes? A) the primitive structure of plants B) meteorites that have struck Earth C) abiotic laboratory experiments that produced liposomes D) Liposomes closely resemble prokaryotic cells. E) The oldest fossilized cells resemble prokaryotes.
Answer: E
34) In snapdragons, heterozygotes for one of the genes have pink flowers, whereas homozygotes have red or white flowers. When plants with red flowers are crossed with plants with white flowers, what proportion of the offspring will have pink flowers? A) 0% B) 25% C) 50% D) 75% E) 100%
Answer: E
34) This is the site in the DNA located near the end of the final exon, encoding an RNA sequence that determines the 3ʹ end of the transcript: A) enhancer B) promoter C) activator D) repressor E) terminator
Answer: E
34) Water passes quickly through cell membranes because A) the bilayer is hydrophilic. B) it moves through hydrophobic channels. C) water movement is tied to ATP hydrolysis. D) it is a small, polar, charged molecule. E) it moves through aquaporins in the membrane.
Answer: E
35) A solution contains 0.0000001(10-7 ) moles of hydroxyl ions [OH - ] per liter. Which of the following best describes this solution? A) acidic: H+ acceptor B) basic: H+ acceptor C) acidic: H+ donor D) basic: H+ donor E) neutral
Answer: E
35) In peas, a gene controls flower color such that R = purple and r = white. In an isolated pea patch, there are 36 purple - flowering plants and 64 white - flowering plants. Assuming Hardy-Weinberg equilibrium, what is the value of q for this population? A) 0.36 B) 0.60 C) 0.64 D) 0.75 E) 0.80
Answer: E
36) To repair a thymine dimmer by nucleotide excision repair, in which order do the necessary enzymes act? A) exonuclease, DNA polymerase III, RNA primase B) helicase, DNA polymerase I, DNA ligase C) DNA ligase, nuclease, helicase D) DNA polymerase I, DNA polymerase III, DNA ligase E) endonuclease, DNA polymerase I, DNA ligase
Answer: E
37) If a pharmaceutical company wished to design a drug to maintain low blood sugar levels, one approach might be to A) design a compound that blocks epinephrine receptor activation. B) design a compound that inhibits cAMP production in liver cells. C) design a compound to block G -protein activity in liver cells. D) design a compound that inhibits phosphorylase activity. E) All of the above are possible approaches.
Answer: E
38) A researcher found a method she could use to manipulate and quantify phosphorylation and methylation in embryonic cells in culture. One of her colleagues suggested she try increased methylation of C nucleotides in a mammalian system. Which of the following results would she most likely see? A) increased chromatin condensation B) decreased chromatin concentration C) abnormalities of mouse embryos D) decreased binding of transcription factors E) inactivation of the selected genes
Answer: E
38) Evolution is biologyʹs core theme that ties together all the other themes. This is because evolution explains A) the unity and diversity of life. B) how organisms become adapted to their environment through the differential reproductive success of varying individuals. C) why distantly related organisms sometimes resemble each other. D) explains why some organisms have traits in common. E) all of the above
Answer: E
38) What is the most probable hypothesis about these intermediate forms of cell division? A) They represent a form of cell reproduction which must have evolved completely separately from those of other organisms. B) They demonstrate that these species are not closely related to any of the other Protists and may well be a different Kingdom. C) They rely on totally different proteins for the processes they undergo. D) They may be more closely related to plant forms that also have unusual mitosis. E) They show some of the evolutionary steps toward complete mitosis but not all.
Answer: E
39) Which of the structures contain(s) a carboxyl functional group? A) A B) B C) C D) C and E E) none of the structures
Answer: E
4) Multigene families are A) groups of enhancers that control transcription. B) usually clustered at the telomeres. C) equivalent to the operons of prokaryotes. D) sets of genes that are coordinately controlled. E) identical or similar genes that have evolved by gene duplication.
Answer: E
4) Which of the following factors would not contribute to allopatric speciation? A) A population becomes geographically isolated from the parent population. B) The separated population is small, and genetic drift occurs. C) The isolated population is exposed to different selection pressures than the ancestral population. D) Different mutations begin to distinguish the gene pools of the separated populations. E) Gene flow between the two populations is extensive.
Answer: E
4) Which of the following statements is false? A) Atoms of the various elements differ in their number of subatomic particles. B) All atoms of a particular element have the same number of protons in their nuclei. C) The neutrons and protons present in the nucleus of an atom are almost identical in mass; each has a mass of about 1 dalton. D) An atom is the smallest unit of an element that still retains the properties of the element. E) Protons and electrons are electrically charged particles. Protons have one unit of negative charge, and electrons have one unit of positive charge.
Answer: E
4) Which of these illustrates the correct representation of the binomial scientific name for the African lion? A) Panthera leo B) panthera leo C) Panthera leo D) Panthera Leo E) Panthera leo
Answer: E
40) If doubly heterozygous SsNn cactuses were allowed to self-pollinate, the F2 would segregate in which of the following ratios? A) 3 sharp-spined : 1 spineless B) 1 sharp-spined : 2 dull-spined : 1 spineless C) 1 sharp spined : 1 dull -spined : 1 spineless D) 1 sharp-spined : 1 dull-spined E) 9 sharp-spined : 3 dull-spined : 4 spineless
Answer: E
40) If the pH of a solution is decreased from 9 to 8, it means that the A) concentration of H + has decreased to one - tenth (1/10) what it was at pH 9. B) concentration of H + has increased 10- fold (10X) compared to what it was at pH 9. C) concentration of OH- has increased 10- fold (10X) compared to what it was at pH 9. D) concentration of OH- has decreased to one - tenth (1/10) what it was at pH 9. E) Both B and D are correct.
Answer: E
40) Of the following anatomical structures, which is homologous to the wing of a bird? A) Dorsal fin of a shark B) Hindlimb of a kangaroo C) Wing of a butterfly D) Tail fin of a flying fish E) Flipper of a cetacean
Answer: E
40) Which of the following statements is true? A) When signal molecules first bind to receptor tyrosine kinases, the receptors phosphorylate a number of nearby molecules. B) In response to some G-protein-mediated signals, a special type of lipid molecule associated with the plasma membrane is cleaved to form IP3 and calcium. C) In most cases, signal molecules interact with the cell at the plasma membrane and then enter the cell and eventually the nucleus. D) Toxins such as those that cause botulism and cholera interfere with the ability of activated G proteins to hydrolyze GTP to GDP, resulting in phosphodiesterase activity in the absence of an appropriate signal molecule. E) Protein kinase A activation is one possible result of signal molecules binding to G protein- linked receptors.
Answer: E
42) A cell whose cytoplasm has a concentration of 0.02 molar glucose is placed in a test tube of water containing 0.02 molar glucose. Assuming that glucose is not actively transported into the cell, which of the following terms describes the tonicity of the external solution relative to the cytoplasm of the cell? A) turgid B) hypertonic C) hypotonic D) flaccid E) isotonic
Answer: E
42) Accuracy in the translation of mRNA into the primary structure of a polypeptide depends on specificity in the A) binding of ribosomes to mRNA. B) shape of the A and P sites of ribosomes. C) bonding of the anticodon to the codon. D) attachment of amino acids to tRNAs. E) both C and D
Answer: E
42) Which curve was most likely generated from an enzyme that requires a cofactor? A) curve 1 B) curve 2 C) curve 4 D) curve 5 E) It is not possible to determine whether an enzyme requires a cofactor from these data.
Answer: E
43) From the descriptions above, which of the following is the order that most logically illustrates a sequence of meiosis? A) 1, 2, 3, 4, 5 B) 5, 4, 2, 1, 3 C) 5, 3, 2, 4, 1 D) 4, 5, 2, 1, 3 E) 5, 2, 4, 3, 1
Answer: E
43) If the frequency of a particular allele that is present in a small, isolated population of alpine plants decreases due to a landslide that leaves an even smaller remnant of surviving plants bearing this allele, then what has occurred? A) a bottleneck B) genetic drift C) microevolution D) A and B only E) A, B, and C
Answer: E
43) One liter of a solution pH 9 has how many more hydroxyl ions (OH - ) than 1 L of a solution of pH 4? A) 5 times more B) 100 times more C) 1,000 times more D) 10,000 times more E) 100,000 times more
Answer: E
44) If the original finches that had been blown over to the Galapagos from South America had already been genetically different from the parental population of South American finches, even before adapting to the Galapagos, this would have been an example of A) genetic drift. B) bottleneck effect. C) founderʹs effect. D) all three of these E) both A and C
Answer: E
44) What is the primary function of the Calvin cycle? A) use ATP to release carbon dioxide B) use NADPH to release carbon dioxide C) split water and release oxygen D) transport RuBP out of the chloroplast E) synthesize simple sugars from carbon dioxide
Answer: E
44) Which is a functional group that helps stabilize proteins by forming covalent cross - links within or between protein molecules?
Answer: E
45) Buffers are substances that help resist shifts in pH by A) releasing H+ in acidic solutions. B) donating H+ to a solution when they have been depleted. C) releasing OH- in basic solutions. D) accepting H+ when the are in excess. E) Both B and D are correct.
Answer: E
45) Logically, which of these should cast the most doubt on the relationships depicted by an evolutionary tree? A) None of the organisms depicted by the tree ate the same foods. B) Some of the organisms depicted by the tree had lived in different habitats. C) The skeletal remains of the organisms depicted by the tree were incomplete (i.e., some bones were missing). D) Transitional fossils had not been found. E) Relationships between DNA sequences among the species did not match relationships between skeletal patterns.
Answer: E
45) Over time, the movement of people on Earth has steadily increased. This has altered the course of human evolution by increasing A) non-random mating. B) geographic isolation. C) genetic drift. D) mutations. E) gene flow.
Answer: E
45) Which bond is closest to the carboxyl end of the molecule?
Answer: E
45) Why is it important that an experiment include a control group? A) The control group is the group that the researcher is in control of; it is the group in which the researcher predetermines the nature of the results. B) The control group provides a reserve of experimental subjects. C) A control group is required for the development of an ʺif, thenʺ statement. D) A control group assures that an experiment will be repeatable. E) Without a control group, there is no basis for knowing if a particular result is due to the variable being tested or to some other factor.
Answer: E
46) The observation that tusks were limited to males in several species, and were apparently not used in food-gathering, is evidence that the tusks probably A) were used by males during the sex act. B) served as heat-dissipation structures. C) are homologous to claws. D) were insignificant to the survival and/or reproduction of dicynodonts. E) were maintained as the result of sexual selection.
Answer: E
47) Natural selection is most nearly the same as A) diploidy. B) gene flow. C) genetic drift. D) non-random mating. E) differential reproductive success.
Answer: E
47) Speciation A) occurs at such a slow pace that no one has ever observed the emergence of new species. B) occurs only by the accumulation of genetic change over vast expanses of time. C) must begin with the geographic isolation of a small, frontier population. D) proceeds at a uniform tempo across all taxa. E) can involve changes involving a single gene.
Answer: E
48) Ichthyosaurs were aquatic dinosaurs. Fossils show us that they had dorsal fins and tails, as do fish, even though their closest relatives were terrestrial reptiles that had neither dorsal fins nor aquatic tails. The dorsal fins and tails of ichthyosaurs and fish are A) homologous. B) examples of convergent evolution. C) adaptations to a common environment. D) A and C only E) B and C only
Answer: E
48) Which of the following statements about speciation is correct? A) The goal of natural selection is speciation. B) When reunited, two allopatric populations will not interbreed. C) Natural selection chooses the reproductive barriers for populations. D) Prezygotic reproductive barriers usually evolve before postzygotic barriers. E) Speciation is a basis for understanding macroevolution.
Answer: E
49) Inside an active mitochondrion, most electrons follow which pathway? A) glycolysis → NADH → oxidative phosphorylation → ATP → oxygen B) citric acid cycle → FADH2 → electron transport chain → ATP C) electron transport chain → citric acid cycle → ATP → oxygen D) pyruvate → citric acid cycle → ATP → NADH → oxygen E) citric acid cycle → NADH → electron transport chain → oxygen
Answer: E
49) The differences among the three categories of cytoskeletal elements would suggest that each of the following has specialized roles. Which of the following is a correct match? A) microfilaments and the nuclear lamina B) microtubules and cleavage furrow formation C) microfilaments and ciliary motion D) intermediate filaments and cytoplasmic streaming E) microtubules and chromosome movement
Answer: E
5) If an enzyme is added to a solution where its substrate and product are in equilibrium, what would occur? A) Additional product would be formed. B) Additional substrate would be formed. C) The reaction would change from endergonic to exergonic. D) The free energy of the system would change. E) Nothing; the reaction would stay at equilibrium.
Answer: E
5) The biggest problem with the shotgun technique is its tendency to underestimate the size of the genome. Which of the following might best account for this? A) skipping some of the clones to be sequenced B) missing some of the overlapping regions of the clones C) counting some of the overlapping regions of the clones twice D) having some of the clones die during the experiment and therefore not be represented E) missing some duplicated sequences
Answer: E
5) Which of the following correctly lists the order in which cellular components will be found in the pellet when homogenized cells are treated with increasingly rapid spins in a centrifuge? A) ribosomes, nucleus, mitochondria B) chloroplasts, ribosomes, vacuoles C) nucleus, ribosomes, chloroplasts D) vacuoles, ribosomes, nucleus E) nucleus, mitochondria, ribosomes
Answer: E
50) Centrioles, cilia, flagella, and basal bodies have remarkably similar structural elements and arrangements. This leads us to which of the following as a probable hypothesis? A) Disruption of one of these types of structure should necessarily disrupt each of the others as well. B) Loss of basal bodies should lead to loss of all cilia, flagella, and centrioles. C) Motor proteins such as dynein must have evolved before any of these four kinds of structure. D) Evolution of motility, of cells or of parts of cells, must have occurred only once. E) Natural selection for motility must select for microtubular arrays in circular patterns.
Answer: E
50) Consider two solutions: solution X has a pH of 4; solution Y has a pH of 7. From this information, we can reasonably conclude that A) solution Y has no free hydrogen ions (H+ ). B) the concentration of hydrogen ions in solution X is 30 times as great as the concentration of hydrogen ions in solution Y. C) the concentration of hydrogen ions in solution Y is 1,000 times as great as the concentration of hydrogen ions in solution X. D) the concentration of hydrogen ions in solution X is 3 times as great as the concentration of hydrogen ions in solution Y. E) None of the other answer choices correctly describes these solutions.
Answer: E
50) From the following list, which is the first event in translation in eukaryotes? A) elongation of the polypeptide B) base pairing of activated methionine- tRNA to AUG of the messenger RNA C) the larger ribosomal subunit binds to smaller ribosomal subunits D) covalent bonding between the first two amino acids E) the small subunit of the ribosome recognizes and attaches to the 5ʹ cap of mRNA
Answer: E
50) In order for speciation to occur, what is true? A) The number of chromosomes in the genome must change. B) Changes to centromere location or chromosome size must occur within the genome. C) Large numbers of genes that affect a single phenotypic trait must change. D) Large numbers of genes that affect numerous phenotypic traits must change. E) At least one gene, affecting at least one phenotypic trait, must change.
Answer: E
50) Since Watson and Crick described DNA in 1953, which of the following might best explain why the function of small RNAs is still being explained? A) As RNAs have evolved since that time, they have taken on new functions. B) Watson and Crick described DNA but did not predict any function for RNA. C) The functions of small RNAs could not be approached until the entire human genome was sequenced. D) Ethical considerations prevented scientists from exploring this material until recently. E) Changes in technology as well as our ability to determine how much of the DNA is expressed have now made this possible.
Answer: E
50) What results from the chemical reaction illustrated in Figure 2.3? A) a cation with a net charge of +1 B) a cation with a net charge of -1 C) an anion with a net charge of +1 D) an anion with a net charge of -1 E) A and D
Answer: E
51) The dicynodonts that survived the Permian extinction would initially have had to endure (or escape from) the physical effects of __________, and subsequently, the biological effects of __________. A) warm temperatures, decreased metabolism B) arid conditions, disease C) meteorite shock waves, lack of food D) increased sea level, lack of freshwater E) volcanic ash in the atmosphere, increased predation
Answer: E
51) When a plant cell, such as one from a peony stem, is submerged in a very hypotonic solution, what is likely to occur? A) the cell will burst B) the cell membrane will lyse C) plasmolysis will shrink the interior D) the cell will become flaccid E) the cell will become turgid
Answer: E
53) At which phase(s) is it preferable to obtain chromosomes to prepare a karyotype? A) Early prophase B) Late telophase C) Anaphase D) Late anaphase or early telophase E) Late prophase or metaphase
Answer: E
53) Genetic engineering is being used by the pharmaceutical industry. Which of the following is not currently one of the uses? A) production of human insulin B) production of human growth hormone C) production of tissue plasminogen activator D) genetic modification of plants to produce vaccines E) creation of products that will remove poisons from the human body
Answer: E
53) Microfilaments are well known for their role in which of the following? A) ameboid movement B) formation of cleavage furrows C) contracting of muscle cells D) A and B only E) A, B, and C
Answer: E
53) What are the membrane structures that function in active transport? A) peripheral proteins B) carbohydrates C) cholesterol D) cytoskeleton filaments E) integral proteins
Answer: E
54) A 100 mL beaker contains 10 mL of NaOH solution at pH = 13. A technician carefully pours into the beaker, 10 mL of HCl at pH = 1. Which of the following statements correctly describes the results of this mixing? A) The concentration of Na+ ion rises. B) The concentration of Cl- ion falls. C) The concentration of undissociated H 2O molecules remains unchanged. D) The pH of the beakerʹs contents rises. E) The pH of the beakerʹs contents falls.
Answer: E
54) Glucose diffuses slowly through artificial phospholipid bilayers. The cells lining the small intestine, however, rapidly move large quantities of glucose from the glucose -rich food into their glucose-poor cytoplasm. Using this information, which transport mechanism is most probably functioning in the intestinal cells? A) simple diffusion B) phagocytosis C) active transport pumps D) exocytosis E) facilitated diffusion
Answer: E
54) If ATP used by this plant is labeled with radioactive phosphorus, in which molecules will the radioactivity be measurable after one ʺturnʺ of the cycle? A) in B only B) in B and C only C) in B, C, and D only D) in B and E only E) in B, C, D, and E
Answer: E
55) As rat pups mature, the growth of their snouts and tails outpaces growth of the rest of their bodies, producing the appearance of sexually mature males. It is found that sexually mature female rats prefer to mate with mutant, sexually mature males that possess snouts and tails with juvenile proportions. Which of the following terms is (are) appropriately applied to this situation? A) sexual selection B) paedomorphosis C) allometric growth D) B and C only E) A, B, and C
Answer: E
55) For a species with a haploid number of 23 chromosomes, how many different combinations of maternal and paternal chromosomes are possible for the gametes? A) 23 B) 46 C) 460 D) 920 E) About 8 million
Answer: E
56) The cyclin component of MPF is destroyed toward the end of this phase: A) G0 B) G1 C) S D) G2 E) M
Answer: E
57) In metabolic processes of cell respiration and photosynthesis, prosthetic groups such as heme and iron-sulfur complexes are encountered. What do they do? A) donate electrons B) act as reducing agents C) act as oxidizing agents D) transport protons within the mitochondria and chloroplasts E) both oxidize and reduce during electron transport
Answer: E
58) If a membrane protein in an animal cell is involved in the cotransport of glucose and sodium ions into the cell, which of the following is most likely true? A) The sodium ions are moving down their electrochemical gradient while glucose is moving up. B) Glucose is entering the cell along its concentration gradient. C) Sodium ions can move down their electrochemical gradient through the cotransporter whether or not glucose is present outside the cell. D) Potassium ions move across the same gradient as sodium ions. E) A substance that blocked sodium ions from binding to the cotransport protein would also block the transport of glucose.
Answer: E
59) In each fly species, the entire body segment that gave rise to the original flight wings is missing. The mutation(s) that led to the flightless condition could have A) duplicated all of the Hox genes in these fliesʹ genomes. B) altered the nucleotide sequence within a Hox gene. C) altered the expression of a Hox gene. D) either A or B E) either B or C
Answer: E
59) When we say that an individual organism has a greater fitness than another individual, we specifically mean that the organism A) lives longer than others of its species. B) competes for resources more successfully than others of its species. C) mates more frequently than others of its species. D) utilizes resources more efficiently than other species occupying similar niches. E) leaves more viable offspring than others of its species.
Answer: E
59) Which enzyme causes a covalent bond to attach lysine to the polypeptide? A) ATPase B) lysine synthetase C) RNA polymerase D) ligase E) peptidyl transferase
Answer: E
59) Why would Gleevec most probably cause remission of the disease? A) It reverses the chromosomal translocation. B) It eliminates the Phʹ chromosome. C) It removes Phʹ-containing progenitor cells. D) The drug inhibits the replication of the affected chromosome. E) The drug inhibits the specific thymine kinase receptor.
Answer: E
6) A lack of this nonprotein molecule would result in the inability of the cell to ʺturn offʺ genes: A) operon B) inducer C) promoter D) repressor E) corepressor
Answer: E
6) In autotrophic bacteria, where are the enzymes located that can carry on organic synthesis? A) chloroplast membranes B) nuclear membranes C) free in the cytosol D) along the outer edge of the nucleoid E) along the inner surface of the plasma membrane
Answer: E
6) The drug cytochalasin B blocks the function of actin. Which of the following aspects of the cell cycle would be most disrupted by cytochalasin B? A) spindle formation B) spindle attachment to kinetochores C) DNA synthesis D) cell elongation during anaphase E) cleavage furrow formation
Answer: E
6) Which of the following mutations would be most likely to have a harmful effect on an organism? A) a base-pair substitution B) a deletion of three nucleotides near the middle of a gene C) a single nucleotide deletion in the middle of an intron D) a single nucleotide deletion near the end of the coding sequence E) a single nucleotide insertion downstream of, and close to, the start of the coding sequence
Answer: E
6) Which of the following statements about the DNA in one of your brain cells is true? A) Most of the DNA codes for protein. B) The majority of genes are likely to be transcribed. C) Each gene lies immediately adjacent to an enhancer. D) Many genes are grouped into operon- like clusters. E) It is the same as the DNA in one of your heart cells.
Answer: E
60) If the foods preferred by each species are found on different parts of the island, and if the flies mate and lay eggs on their food sources, regardless of the location of the food sources, then the speciation events involving these fly species may have been driven, at least in part, by which of the following? A) autopolyploidy B) allopolyploidy C) species selection D) genetic drift E) habitat differentiation
Answer: E
60) What is the probability that individual III -1 is Ww? A) 3/4 B) 1/4 C) 2/4 D) 2/3 E) 1
Answer: E
60) Which of the following statements best summarizes evolution as it is viewed today? A) It is goal-directed. B) It represents the result of selection for acquired characteristics. C) It is synonymous with the process of gene flow. D) It is the descent of humans from the present -day great apes. E) It is the differential survival and reproduction of the most - fit phenotypes.
Answer: E
61) Approximately what percentage of the energy of glucose (C 6H12O6 ) is transferred to storage in ATP as a result of the complete oxidation of glucose to CO 2 and water in cellular respiration? A) 2% B) 4% C) 10% D) 25% E) 40%
Answer: E
61) People with sickle-cell trait A) are heterozygous for the sickle-cell allele. B) are usually healthy. C) have increased resistance to malaria. D) produce normal and abnormal hemoglobin. E) All of the above
Answer: E
61) What mechanisms do plants use to load sucrose produced by photosynthesis into specialized cells in the veins of leaves? A) an electrogenic pump B) a proton pump C) a contransport protein D) A and C only E) A, B, and C
Answer: E
61) Which of the following would be regarded as compounds? A) H2 B) H2O C) O2 D) CH4 E) B and D, but not A and C
Answer: E
62) Fly species W, found in a certain part of the island, produces fertile offspring with species Y. Species W does not produce fertile offspring with species X or Z. If no other species can hybridize, then species W and Y A) have genomes that are still similar enough for successful meiosis to occur in hybrid flies. B) have more genetic similarity with each other than either did with the other two species. C) may fuse into a single species if their hybrids remain fertile over the course of many generations. D) A and B only E) A, B, and C
Answer: E
63) Ions can travel directly from the cytoplasm of one animal cell to the cytoplasm of an adjacent cell through A) plasmodesmata. B) intermediate filaments. C) tight junctions. D) desmosomes. E) gap junctions.
Answer: E
63) Proteins that are involved in the regulation of the cell cycle, and that show fluctuations in concentration during the cell cycle, are called A) ATPases. B) kinetochores. C) centrioles. D) proton pumps. E) cyclins.
Answer: E
63) The function of each protein is a consequence of its specific shape. What is the term used for a change in a proteinʹs three -dimensional shape or conformation due to disruption of hydrogen bonds, disulfide bridges, or ionic bonds? A) hydrolysis B) stabilization C) destabilization D) renaturation E) denaturation
Answer: E
63) Which describes brightly colored peacocks mating more frequently than drab peacocks? A) artificial selection B) directional selection C) stabilizing selection D) disruptive selection E) sexual selection
Answer: E
64) Several seriously epidemic viral diseases of earlier centuries were then incurable because they resulted in severe dehydration due to vomiting and diarrhea. Today they are usually not fatal because we have developed which of the following? A) antiviral medications that are efficient and work well with all viruses B) antibiotics against the viruses in question C) intravenous feeding techniques D) medication to prevent blood loss E) hydrating drinks that include high concentrations of salts and glucose
Answer: E
65) A mutation results in a cell that no longer produces a normal protein kinase for the M phase checkpoint. Which of the following would likely be the immediate result of this mutation? A) The cell would prematurely enter anaphase. B) The cell would never leave metaphase. C) The cell would never enter metaphase. D) The cell would never enter prophase. E) The cell would undergo normal mitosis, but fail to enter the next G 1 phase.
Answer: E
67) In coupled reactions, in which direction would the endergonic reaction be driven relative to the clockwise direction of the ATP reaction above and shown in the figure? A) from left to right at the top of the figure B) under the symbol for energy doing cellular work in the figure C) from right to left at the bottom of the figure D) it would be shown separately after the figure E) it would be shown in a clockwise direction at the top of the figure
Answer: E
67) It should be possible to reconstitute the abilities of the vesicles if which of the following is added? A) cytochromes B) extra NADH C) a second membrane surface D) more electrons E) intact ATP synthase
Answer: E
68) Which of the following describe(s) cyclin-dependent kinase (Cdk)? A) Cdk is inactive, or ʺturned off,ʺ in the presence of cyclin. B) Cdk is present throughout the cell cycle. C) Cdk is an enzyme that attaches phosphate groups to other proteins. D) Both A and B are true. E) Both B and C are true.
Answer: E
68) Your brother has just purchased a new plastic model airplane. He places all the parts on the table in approximately the positions in which they will be located when the model is complete. His actions are analogous to which process in development? A) morphogenesis B) determination C) induction D) differentiation E) pattern formation
Answer: E
7) For a science fair project, two students decided to repeat the Hershey and Chase experiment, with modifications. They decided to label the nitrogen of the DNA, rather than the phosphate. They reasoned that each nucleotide has only one phosphate and two to five nitrogens. Thus, labeling the nitrogens would provide a stronger signal than labeling the phosphates. Why wonʹt this experiment work? A) There is no radioactive isotope of nitrogen. B) Radioactive nitrogen has a half - life of 100,000 years, and the material would be too dangerous for too long. C) Avery et al. have already concluded that this experiment showed inconclusive results. D) Although there are more nitrogens in a nucleotide, labeled phosphates actually have 16 extra neutrons; therefore, they are more radioactive. E) Amino acids (and thus proteins) also have nitrogen atoms; thus, the radioactivity would not distinguish between DNA and proteins.
Answer: E
7) Which structure- function pair is mismatched? A) nucleolus; production of ribosomal subunits B) lysosome; intracellular digestion C) ribosome; protein synthesis D) Golgi; protein trafficking E) microtubule; muscle contraction
Answer: E
70) The parts of the figure labeled with Roman numerals symbolize what concept? A) different inner mitochondrial membranes B) different mitochondria functioning together C) molecules with different attached metal ions D) carbohydrate framework holding the molecules in place E) multimeric groups of proteins in 4 complexes
Answer: E
71) A frameshift mutation could result from A) a base insertion only. B) a base deletion only. C) a base substitution only. D) deletion of three consecutive bases. E) either an insertion or a deletion of a base.
Answer: E
72) Which of the following couples chemiosmosis to energy storage? A) NADH B) FADH2 C) cytochromes D) electron transport E) ATP synthase
Answer: E
75) Gene expression in Archaea differs from that in other prokaryotes. It shares features with which of the following? A) eubacteria only B) eukaryotes only C) protists only D) fungi only E) bacteria and eukaryotes
Answer: E
76) In the double helix structure of nucleic acids, cytosine hydrogen bonds to A) deoxyribose. B) ribose. C) adenine. D) thymine. E) guanine.
Answer: E
78) A proficient engineer can easily design skeletal structures that are more functional than those currently found in the forelimbs of such diverse mammals as horses, whales, and bats. That the actual forelimbs of these mammals do not seem to be optimally arranged is because A) natural selection has not had sufficient time to create the optimal design in each case, but will do so given enough time. B) natural selection operates in ways that are beyond the capability of the human mind to comprehend. C) in many cases, phenotype is not merely determined by genotype, but by the environment as well. D) though we may not consider the fit between the current skeletal arrangements and their functions excellent, we should not doubt that natural selection ultimately produces the best design. E) natural selection is generally limited to modifying structures that were present in previous generations and in previous species.
Answer: E
8) A biologist is studying kidney tubules in small mammals. She wants specifically to examine the juxtaposition of different types of cells in these structures. The cells in question can be distinguished by external shape, size, and 3 -dimensional characteristics. Which would be the optimum method for her study? A) transmission electron microscopy B) cell fractionation C) light microscopy using stains specific to kidney function D) light microscopy using living unstained material E) scanning electron microscopy
Answer: E
8) Bacteria containing a plasmid into which the eukaryotic gene has integrated would grow in A) the nutrient broth only. B) the nutrient broth and the tetracycline broth only. C) the nutrient broth, the ampicillin broth, and the tetracycline broth. D) all four types of broth. E) the ampicillin broth and the nutrient broth.
Answer: E
8) If organisms A, B, and C belong to the same class but to different orders and if organisms D, E, and F belong to the same order but to different families, which of the following pairs of organisms would be expected to show the greatest degree of structural homology? A) A and B B) A and C C) B and D D) C and F E) D and F
Answer: E
8) What is a karyotype? A) The set of unique physical characteristics that define an individual B) The collection of all the mutations present within the genome of an individual C) The combination of chromosomes found in a gamete D) A system of classifying cell nuclei E) A display of every pair of homologous chromosomes within a cell, organized according to size and shape
Answer: E
8) one daughter nucleus at telophase of mitosis
Answer: E
81) An organism is discovered that consumes a considerable amount of sugar, yet does not gain much weight when denied air. Curiously, the consumption of sugar increases as air is removed from the organismʹs environment, but the organism seems to thrive even in the absence of air. When returned to normal air, the organism does fine. Which of the following best describes the organism? A) It must use a molecule other than oxygen to accept electrons from the electron transport chain. B) It is a normal eukaryotic organism. C) The organism obviously lacks the citric acid cycle and electron transport chain. D) It is an anaerobic organism. E) It is a facultative anaerobe.
Answer: E
88) Phosphofructokinase is an important control enzyme in the regulation of cellular respiration. Which of the following statements describes a function of phosphofructokinase? A) It is activated by AMP (derived from ADP). B) It is activated by ATP. C) It is inhibited by citrate, an intermediate of the citric acid cycle. D) It catalyzes the conversion of fructose-1,6-bisphosphate to fructose-6-phosphate, an early step of glycolysis. E) It is an allosteric enzyme.
Answer: E
9) The nucleus of a nitrogen atom contains 7 neutrons and 7 protons. Which of the following is a correct statement concerning nitrogen? A) The nitrogen atom has a mass number of approximately 7 daltons and an atomic mass of 14. B) The nitrogen atom has a mass number of approximately 14 daltons and an atomic mass of 7. C) The nitrogen atom has a mass number of 14 and an atomic mass of 7 grams. D) The nitrogen atom has a mass number of 7 grams and an atomic number of 14. E) The nitrogen atom has a mass number of 14 and an atomic mass of approximately 14 daltons.
Answer: E
9) What is the chromosomal system for sex determination in birds? A) Haploid-diploid B) X-0 C) X-X D) X-Y E) Z-W
Answer: E
9) Where does glycolysis takes place? A) mitochondrial matrix B) mitochondrial outer membrane C) mitochondrial inner membrane D) mitochondrial intermembrane space E) cytosol
Answer: E
91) In vertebrate animals, brown fat tissueʹs color is due to abundant mitochondria. White fat tissue, on the other hand, is specialized for fat storage and contains relatively few mitochondria. Brown fat cells have a specialized protein that dissipates the proton -motive force across the mitochondrial membranes. Which of the following might be the function of the brown fat tissue? A) to increase the rate of oxidative phosphorylation from its few mitochondria B) to allow the animals to regulate their metabolic rate when it is especially hot C) to increase the production of ATP synthase D) to allow other membranes of the cell to perform mitochondrial function E) to regulate temperature by converting energy from NADH oxidation to heat
Answer: E
92) What is the purpose of beta oxidation in respiration? A) oxidation of glucose B) oxidation of pyruvate C) feedback regulation D) control of ATP accumulation E) breakdown of fatty acids
Answer: E
97) Which of the following molecules contains a glycosidic linkage type of covalent bond? A) 4 B) 6 C) 12 D) 13 E) 15
Answer: E
47) A common form of regulation in which accumulation of an end product of a process slows that process is called positive feedback.
Answer: FALSE
48) Charles Darwin presented verifiable evidence that supported the view that life can arise by spontaneous generation.
Answer: FALSE
54) A theory in science is equivalent in scope to a well-structured hypothesis.
Answer: FALSE
55) The goal of systems biology is to construct models to predict the emergent properties of cells.
Answer: FALSE
18) A man with type A blood marries a woman with type B blood. Their child has type O blood. What are the genotypes of these individuals? What other genotypes, and in what frequencies, would you expect in offspring from this marriage?
Answer: Man IAi ; woman IBi ; child ii. Other genotypes for children are 1⁄4 IAIB, 1⁄4 IAi , 1⁄4 IBi.
50) Discovery science uses inductive reasoning to derive generalizations from a large number of specific observations.
Answer: TRUE
8) Use the unlabeled clock diagram below to test your memory of the sequence of key events in the history of life on Earth described in this chapter by labeling the colored bars. As a visual aid to help you study, add labels that represent other significant events discussed in the chapter, such as the Cambrian explosion, origin of mammals, and Permian and
Cretaceous mass extinctions.
56) The R group or side chain of the amino acid serine is —CH 2 chain of the amino acid alanine is —CH 3 . Where would you expect to find these amino acids in a globular protein in aqueous solution? A) Serine would be in the interior, and alanine would be on the exterior of the globular protein. B) Alanine would be in the interior, and serine would be on the exterior of the globular protein. C) Both serine and alanine would be in the interior of the globular protein. D) Both serine and alanine would be on the exterior of the globular protein. E) Both serine and alanine would be in the interior and on the exterior of the globular protein.
OH. The R group or sideAnswer: B
2) Pseudohypertrophic muscular dystrophy is an inherited disorder that causes gradual deterioration of the muscles. It is seen almost exclusively in boys born to apparently normal parents and usually results in death in the early teens. Is this disorder caused by a dominant or a recessive allele? Is its inheritance sex - linked or autosomal? How do you know? Explain why this disorder is almost never seen in girls. Answer: Recessive; if the disorder were dominant, it would affect at least one parent of a child born with the disorder. The disorderʹs inheritance is sex- linked because it is seen only in boys. For a girl to have the disorder, she would have to inherit recessive alleles from both parents. This would be very rare, since males with the recessive
allele on their X chromosome die in their early teens.
25) Blue light is that portion of the visible spectrum that penetrates the deepest into bodies of water. Ultraviolet (UV) light, though, can penetrate even deeper. A gene within a population of marine fish that inhabits depths from 500 m to 1,000 m has an allele for a photopigment that is sensitive to UV light, and another allele for a photopigment that is sensitive to blue light. Which graph below best depicts the predicted distribution of these
alleles if the fish that carry these alleles prefer to locate themselves where they can see best?
L) A heritable feature that varies
among individuals
27) Thalidomide and L-dopa, shown below, are examples of pharmaceutical drugs that occur
as enantiomers, or molecules that
9) Draw Lewis structures for each hypothetical molecule shown below, using the correct number of valence electrons for each atom. Determine which molecule makes sense because each atom has a complete valence shell and each bond has the correct number of electrons. Explain what makes the other molecules nonsensical, considering the number of
bonds each type of atom can make.
5) Which of the following people used this apparatus to study formation of organic
compounds?
J) A heritable unit that determines a character and can exist in
different forms.
53) The researcher measures the concentration of the polypeptides from different regions in the
early embryo and finds the following pattern (darker shading = greater concentration):
3) Atoms can be represented by simply listing the number of protons, neutrons, and electrons isotope of oxygen? A) 6p+ ; 8n0 ; 6e- B) 8p+ ; 10n0 ; 8e- C) 9p+ ; 9n0 ; 9e- D) 7p+ ; 2n0 ; 9e- E) 10p+ ; 8n0 ; 9e-
for example, 2p+ ; 2n0 ; 2e- for helium. Which one of the following lists represents the 18OAnswer: B
B) Determines phenotype in a
heterozygote
5) In another cross, a wild- type fruit fly (heterozygous for gray body color and red eyes) is mated with a black fruit fly with purple eyes. The offspring are as follows: wild type, 721; black-purple, 751; gray -purple, 49; black-red, 45. What is the recombination frequency between these genes for body color and eye color? Using information from problem 4, what fruit flies (genotypes and phenotypes) would you mate to determine the sequence of the body-color, wing-size, and eye-color genes on the chromosome? Answer: 6%. Wild type (heterozygous for normal wings and red eyes) × recessive
homozygote with vestigial wings and purple eyes
26) A small birthday candle is weighed, then lighted and placed beneath a metal can containing 100 mL of water. Careful records are kept as the temperature of the water rises. Data from this experiment are shown on the graph. What amount of heat energy is released
in the burning of candle wax?
13) You design Drosophila crosses to provide recombination data for gene a, which is located on the chromosome shown in Figure 15.12 in the textbook. Gene a has recombination frequencies of 14% with the vestigial-wing locus and 26% with the brown -eye locus. Where is a located on the chromosome? Answer: About one- third of the distance from the vestigial-wing locus to the brown-eye
locus
11) With rough sketches, draw a biological hierarchy similar to the one in Figure 1.4 in the text but using a coral reef as the ecosystem, a fish as the organism, its stomach as the organ, and DNA as the molecule. Include all levels in the hierarchy. Answer: Your figure should show: (1) For the biosphere, the Earth with an arrow coming out of a tropical ocean; (2) for the ecosystem, a distant view of a coral reef; (3) For the community, a collection of reef animals and algae, with corals, fishes, some seaweed, and any other organisms you can think of; (4) for the population, a group of fish of the same species; (5) for the organism, one fish from your population; (6) for the organ, the fishʹs stomach, and for the organ system, the whole digestive tract (see Chapter 41 for help); (7) for a tissue, a group of similar cells from the stomach; (8) for a cell, one cell from the tissue, showing its nucleus and a few other organelles; (9) for an organelle, the nucleus, where most of the cellʹs DNA is located; and (10) for a
molecule, a DNA double helix. Your sketches can be very rough!
3) Choose the term that correctly describes the relationship between these two sugar
molecules:
A) An organismʹs appearance or
observable traits
23) In 1981, a stray black cat with unusual rounded, curled -back ears was adopted by a family in California. Hundreds of descendants of the cat have since been born, and cat fanciers hope to develop the curl cat into a show breed. Suppose you owned the first curl cat and wanted to develop a true -breeding variety. How would you determine whether the curl allele is dominant or recessive? How would you obtain true -breeding curl cats? How could you be sure they are true -breeding? Answer: Matings of the original mutant cat with true-breeding noncurl cats will produce both curl and noncurl F 1 offspring if the curl allele is dominant, but only noncurl offspring if the curl allele is recessive. You would obtain some true -breeding offspring homozygous for the curl allele from matings between the F 1 cats resulting from the original curl × noncurl crosses whether the curl trait is dominant or recessive. You know that cats are true-breeding when curl × curl matings produce
only curl offspring. As it turns out, the allele that causes curled ears is dominant.
27) The pedigree below traces the inheritance of alkaptonuria, a biochemical disorder. Affected individuals, indicated here by the colored circles and squares, are unable to metabolize a substance called alkapton, which colors the urine and stains body tissues. Does alkaptonuria appear to be caused by a dominant allele or by a recessive allele? Fill in the genotypes of the individuals whose genotypes can be deduced. What genotypes are
possible for each of the other individuals?
17) In sesame plants, the one -pod condition (P) is dominant to the three-pod condition (p ), and normal leaf (L) is dominant to wrinkled leaf ( l). Pod type and leaf type are inherited independently. Determine the genotypes for the two parents for all possible matings producing the following offspring: A) 318 one -pod, normal leaf and 98 one-pod, wrinkled leaf B) 323 three-pod, normal leaf and 106 three-pod, wrinkled leaf C) 401 one-pod, normal leaf D) 150 one -pod, normal leaf, 147 one -pod, wrinkled leaf, 51 three -pod, normal leaf, and 48 three-pod, wrinkled leaf E) 223 one -pod, normal leaf, 72 one-pod, wrinkled leaf, 76 three -pod, normal leaf, and 27 three-pod, wrinkled leaf Answer: A) PPLl × PPLl, PPLl × PpLl, or PPLl × ppLl. B) ppLl × ppLl. C) PPLL × any of the 9
possible genotypes or PPll × ppLL. D) PpLl × Ppll. E) PpLl × PpLl.
10) The graph here shows the pH difference across the inner mitochondrial membrane over time in an actively respiring cell. At the time indicated by the vertical arrow, a metabolic poison is added that specifically and completely inhibits all function of mitochondrial ATP
synthase. Draw what you would expect to see for the rest of the graphed line.
14) In some plants, a true-breeding, red- flowered strain gives all pink flowers when crossed with a white- flowered strain: CRCR (red) × CWCW (white) → CRCW (pink). If flower position (axial or terminal) is inherited as it is in peas (see Table 14.1 in your textbook), what will be the ratios of genotypes and phenotypes of the F 1 generation resulting from the following cross: axial-red (true-breeding) × terminal-white? What will be the ratios in the F2 generation? Answer: Parental cross is AACRCR × aaCWCW. Genotype of F1 is AaCRCW, phenotype is all axial-pink. Genotypes of F2 are 4 AaCRCW : 2 AaCRCR : 2 AACRCW : 2 aaCRCW : 2 AaCWCW : 1 AACRCR : 1 aaCRCR : 1 AACWCW : 1 aaCWCW. Phenotypes of F2 are 6 axial-pink : 3 axial -red : 3 axial-white : 2 terminal-pink : 1 terminal-white : 1
terminal- red.
10) Assume that genes A and B are linked and are 50 map units apart. An animal heterozygous at both loci is crossed with one that is homozygous recessive at both loci. What percentage of the offspring will show phenotypes resulting from crossovers? If you did not know that genes A and B were linked, how would you interpret the results of this cross? Answer: Fifty percent of the offspring would show phenotypes that resulted from crossovers. These results would be the same as those from a cross where A and B were not linked. Further crosses involving other genes on the same chromosome would reveal
the linkage and map distances.
43) A part of an mRNA molecule with the following sequence is being read by a ribosome: 5ʹ CCG-ACG 3ʹ (mRNA). The following charged transfer RNA molecules (with their anticodons shown in the 3ʹ to 5ʹ direction) are available. Two of them can correctly match
the mRNA so that a dipeptide can form.
10) A microarray known as a GeneChip, with most now known human protein coding sequences, has recently been developed to aid in the study of human cancer by first comparing two gleaned from this GeneChip to aid in cancer prevention? A) information about whether or not a patient has this type of cancer prior to treatment. B) evidence that might suggest how best to treat a personʹs cancer with chemotherapy. C) data that could alert patients to what kind of cancer they were likely to acquire. D) information about which parent might have provided a patient with cancer -causing genes. E) information on cancer epidemiology in the U.S. or elsewhere.
three subsets of cancer subtypes. What kind of information might beAnswer: C
14) Bananas plants, which are triploid, are seedless and therefore sterile. Propose a possible explanation. Answer: Because bananas are triploid, homologous pairs cannot line up during meiosis. Therefore, it is not possible to generate gametes that can fuse to produce a zygote
with the triploid number of chromosomes.
19) Phenylketonuria (PKU) is an inherited disease caused by a recessive allele. If a woman and her husband, who are both carriers, have three children, what is the probability of each of the following? A) All three children are of normal phenotype. B) One or more of the three children have the disease. C) All three children have the disease. D) At least one child is phenotypically normal. (Note: Remember that the probabilities of all possible outcomes always add up to 1.) Answer: A) 3⁄4 × 3⁄4 × 3⁄4 = 27⁄64, B) 1 — 27⁄64 = 37⁄64, C) 1⁄4 × 1⁄4 × 1⁄4 = 1⁄64, D) 1 — 1⁄64=63
⁄64
26) In corn plants, a dominant allele I inhibits kernel color, while the recessive allele i permits color when homozygous. At a different locus, the dominant allele P causes purple kernel color, while the homozygous recessive genotype pp causes red kernels. If plants heterozygous at both loci are crossed, what will be the phenotypic ratio of the offspring? Answer: The dominant allele I is epistatic to the P/p locus, and thus the genotypic ratio for the F1 generation will be 9 I_P_ (colorless) : 3 I_pp (colorless) : 3 iiP_ (purple) : 1 iipp
(red). Overall, the phenotypic ratio is 12 colorless : 3 purple : 1 red.
16) A black guinea pig crossed with an albino guinea pig produces 12 black offspring. When the albino is crossed with a second black one, 7 blacks and 5 albinos are obtained. What is the best explanation for this genetic situation? Write genotypes for the parents, gametes, and offspring. Answer: Albino (b) is a recessive trait; black (B) is dominant. First cross: parents BB × bb; gametes B and b; offspring all Bb (black coat). Second cross: parents Bb × bb; gametes
1⁄2 B and 1⁄2 b (heterozygous parent) and b; offspring 1⁄2 Bb and 1⁄/2 bb.
26) Three or four of the pairs of structures shown below depict enantiomers (enantiomeric forms) of the same molecule. Which pair, if any, are NOT enantiomers of a single molecule? If each of the pairs depicts enantiomers, choose answer F.
A)
27) Identical heat lamps are arranged to shine on identical containers of water and methanol (wood alcohol), so that each liquid absorbs the same amount of energy minute by minute. The covalent bonds of methanol molecules are non -polar, so there are no hydrogen bonds among methanol molecules. Which of the following graphs correctly describes what will happen to the temperature of the water and the methanol?
A)
33) The segment of DNA shown in Figure 20.2 has restriction sites I and II, which create restriction fragments A, B, and C. Which of the gels produced by electrophoresis shown below best represents the separation and identity of these fragments?
A)
68) Which of the following pairs of atoms would be most likely to form a covalent bond?
A)
10) Copy Figure 13.5 to a separate sheet of paper and label appropriate structures with these terms, drawing lines or brackets as needed: chromosome (label as replicated or unreplicated), centromere, kinetochore, sister chromatids, nonsister chromatids, homologous pair, homologs, chiasma, sister chromatid cohesion.
Answer:
1) A man with hemophilia (a recessive, sex- linked condition) has a daughter of normal phenotype. She marries a man who is normal for the trait. What is the probability that a daughter of this mating will be a hemophiliac? That a son will be a hemophiliac? If the couple has four sons, what is the probability that all four will be born with hemophilia?
Answer: 0; 1⁄2, 1/16
28) A man has six fingers on each hand and six toes on each foot. His wife and their daughter have the normal number of digits. Extra digits is a dominant trait. What fraction of this coupleʹs children would be expected to have extra digits?
Answer: 1/2
16) Which of these conditions should completely prevent the occurrence of natural selection in a population over time? A) All variation between individuals is due only to environmental factors. B) The environment is changing at a relatively slow rate. C) The population size is large. D) The population lives in a habitat where there are no competing species present.
Answer: A
18) All of the following are polysaccharides except A) glycogen B) starch C) chitin D) cellulose E) amylopectin
Answer: A
23) Which treatment could definitively determine whether or not the component is a viroid? A) I B) II C) III D) IV E) first II and then III
Answer: A
27) The TATA sequence is found only several nucleotides away from the start site of transcription. This most probably relates to which of the following? A) the number of hydrogen bonds between A and T in DNA B) the triplet nature of the codon C) the ability of this sequence to bind to the start site D) the supercoiling of the DNA near the start site E) the 3-dimensional shape of a DNA molecule
Answer: A
33) The most likely explanation for the high rate of sympatric speciation that apparently existed among the cichlids of Lake Victoria in the past is A) sexual selection. B) habitat differentiation. C) polyploidy. D) pollution. E) introduction of a new predator.
Answer: A
39) A cell that has 2n + 1 chromosomes is A) trisomic. B) monosomic. C) euploid. D) polyploid. E) triploid.
Answer: A
50) Which of the following terms best describes when t he phenotype of the heterozygote differs from the phenotypes of both homozygotes? A) Incomplete dominance B) Multiple alleles C) Pleiotropy D) Epistasis
Answer: A
69) Which of the following is established prior to fertilization in Drosophila eggs? A) the anterior-posterior and dorsal-ventral axes B) the position of the future segments C) the position of the future wings, legs, and antennae D) A and B only E) A, B, and C
Answer: A
9) The main source of energy for producers in an ecosystem is A) light energy. B) kinetic energy. C) thermal energy. D) chemical energy. E) ATP.
Answer: A
19) Which of the life cycles is typical for most fungi and some protists? A) I only B) II only C) III only D) I and II E) I and III
Answer: B
37) What is the valence of an atom with six electrons in its outer electron shell? A) 1 B) 2 C) 3 D) 4 E) 5
Answer: B
41) Why isnʹt the mitochondrion classified as part of the endomembrane system? A) It only has two membrane layers. B) Its structure is not derived from the ER. C) It has too many vesicles. D) It is not involved in protein synthesis. E) It is not attached to the outer nuclear envelope.
Answer: B
54) The ʺrestriction pointʺ occurs here: A) G0 B) G1 C) S D) G2 E) M
Answer: B
1) Fossilized stromatolites A) all date from 2.7 billion years ago. B) formed around deep-sea vents. C) resemble structures formed by bacterial communities that are found today in some warm, shallow, salty bays. D) provide evidence that plants moved onto land in the company of fungi around 500 million years ago. E) contain the first undisputed fossils of eukaryotes and date from 2.1 billion years ago.
Answer: C
15) The genetic code is essentially the same for all organisms. From this, one can logically assume all of the following except A) a gene from an organism could theoretically be expressed by any other organism. B) all organisms have a common ancestor. C) DNA was the first genetic material. D) the same codons in different organisms usually translate into the same amino acids. E) different organisms have the same number of different types of amino acids.
Answer: C
21) What are the products of linear photophosphorylation? A) heat and fluorescence B) ATP and P700 C) ATP and NADPH D) ADP and NADP E) P700 and P680
Answer: C
45) Which of the following is a possible phenotype for the father? A) A negative B) O negative C) B positive D) AB negative E) Impossible to determine
Answer: C
54) Which of the following represents the activation energy required for a noncatalyzed reaction? A) a B) b C) c D) d E) e
Answer: C
59) What is the likelihood that the progeny of IV -3 and IV-4 will have wooly hair? A) 0% B) 25% C) 50% D) 75% E) 100%
Answer: C
69) In receptor-mediated endocytosis, receptor molecules initially project to the outside of the cell. Where do they end up after endocytosis? A) on the outside of vesicles B) on the inside surface of the cell membrane C) on the inside surface of the vesicle D) on the outer surface of the nucleus E) on the ER
Answer: C
7) Measurements show that the pH of a particular lake is 4.0. What is the hydrogen ion concentration of the lake? A) 4.0 M B) 10-10 M C) 10-4 M D) 104 M E) 4%
Answer: C
A) They are isomers. B) They are polymers. C) They are isotopes. D) They contain 1 and 3 protons, respectively. E) They each contain 1 neutron.
Answer: C
21) A common ancestor for both species C and E could be at position number A) 1. B) 2. C) 3. D) 4. E) 5.
Answer: D
23) Genomic imprinting, DNA methylation, and histone acetylation are all examples of A) genetic mutation. B) chromosomal rearrangements. C) karyotypes. D) epigenetic phenomena. E) translocation.
Answer: D
29) These three steps result in the formation of A) acetyl CoA, O2 , and ATP. B) acetyl CoA, FADH 2 , and CO 2 . C) acetyl CoA, FAD, H2 , and CO 2 . D) acetyl CoA, NADH, H + , and CO 2 . E) acetyl CoA, NAD+ , ATP, and CO2 .
Answer: D
3) Starting with a fertilized egg (zygote), a series of five cell divisions would produce an early embryo with how many cells? A) 4 B) 8 C) 16 D) 32 E) 64
Answer: D
3) Which of the factors below weaken the hypothesis of abiotic synthesis of organic monomers in early Earthʹs atmosphere? 1. the relatively short time between intense meteor bombardment and appearance of the first life forms 2. the lack of experimental evidence that organic monomers can form by abiotic synthesis 3. uncertainty about which gases comprised early Earthʹs atmosphere A) 1 B) 2 C) 3 D) 1 and 3 E) 2 and 3
Answer: D
3) Which of the following observations helped Darwin shape his concept of descent with modification? A) Species diversity declines farther from the equator. B) Fewer species live on islands than on the nearest continents. C) Birds can be found on islands located farther from the mainland than the birdsʹ maximum nonstop flight distance. D) South American temperate plants are more similar to the tropical plants of South America than to the temperate plants of Europe. E) Earthquakes reshape life by causing mass extinctions.
Answer: D
3) Who proposed that the membrane is a mosaic of protein molecules bobbing in a fluid bilayer of phospholipids? A) H. Davson and J. Danielli B) I. Langmuir C) C. Overton D) S. Singer and G. Nicolson E) E. Gorter and F. Grendel
Answer: D
37) DDT was once considered a ʺsilver bulletʺ that would permanently eradicate insect pests. Today, instead, DDT is largely useless against many insects. Which of these would have been required for this pest eradication effort to be successful in the long run? A) Larger doses of DDT should have been applied. B) All habitats should have received applications of DDT at about the same time. C) The frequency of DDT application should have been higher. D) None of the individual insects should have possessed genomes that made them resistant to DDT. E) DDT application should have been continual.
Answer: D
38) If a speciation event occurred on Sao Tomé, producing D. santomea from a parent colony of D. yakuba, then which terms apply? I. macroevolution II. allopatric speciation III. sympatric speciation A) I only B) II only C) I & II D) I & III
Answer: D
4) This protein is produced by a regulatory gene: A) operon B) inducer C) promoter D) repressor E) corepressor
Answer: D
4) Which structure is common to plant and animal cells? A) chloroplast B) wall made of cellulose C) central vacuole D) mitochondrion E) centriole
Answer: D
51) What is the atomic number of the cation formed in the reaction illustrated in Figure 2.3? A) 1 B) 8 C) 10 D) 11 E) 16
Answer: D
54) In ammonium chloride salt (NH4Cl) the anion is a single chloride ion, Cl- . What is the cation of NH4Cl? A) N, with a charge of +3 B) H, with a charge of +1 C) H2 with a charge of +4 D) NH4 with a charge of +1 E) NH4 with a charge of +4
Answer: D
54) Which molecule can increase the concentration of hydrogen ions in a solution and is therefore an organic acid?
Answer: D
65) An organism with a cell wall would have the most difficulty doing which process? A) diffusion B) osmosis C) active transport D) phagocytosis E) facilitated diffusion
Answer: D
13) Males of one species are too small to perform amplexus (an action that stimulates ovulation) with females of all other species. A) behavioral B) gametic C) habitat D) temporal E) mechanical
Answer: E
39) Which uses reverse transcriptase to make cDNA followed by amplification? A) Southern blotting B) Northern blotting C) Western blotting D) Eastern blotting E) RT-PCR
Answer: E
46) How many different kinds of polypeptides, each composed of 12 amino acids, could be synthesized using the 20 common amino acids? A) 412 B) 1220 C) 125 D) 20 E) 2012
Answer: E
50) Which of the following is a protein maintained at constant levels throughout the cell cycle that requires cyclin to become catalytically active? A) PDGF B) MPF C) protein kinase D) cyclin E) Cdk
Answer: E
85) Forms of the ras protein found in tumors usually cause which of the following? A) DNA replication to stop B) DNA replication to be hyperactive C) cell- to-cell adhesion to be nonfunctional D) cell division to cease E) growth factor signaling to be hyperactive
Answer: E
51) In hypothesis-based science, deductive reasoning is used to predict a result that would be found if a particular hypothesis is correct.
Answer: TRUE
7) What pattern of inheritance would lead a geneticist to suspect that an inherited disorder of cell metabolism is due to a defective mitochondrial gene?
Answer: The disorder would always be inherited from the mother.
42) If an atom of sulfur (atomic number 16) were allowed to react with atoms of hydrogen (atomic number 1), which of the molecules below would be formed? A) S B) H C) H | H H | H | H E) HSH
HS S SAnswer: B
8) Women born with an extra X chromosome (XXX) are healthy and phenotypically indistinguishable from normal XX women. What is a likely explanation for this finding? How could you test this explanation? Answer: The inactivation of two X chromosomes in XXX women would leave them with one genetically active X, as in women with the normal number of chromosomes.
Microscopy should reveal two Barr bodies in XXX women.
6) Which action could produce a carbonyl group? A) the replacement of the B) the addition of a thiol to a hydroxyl C) the addition of a hydroxyl to a phosphate D) the replacement of the nitrogen of an amine with oxygen E) the addition of a sulfhydryl to a carboxyl
OH of a carboxyl group with hydrogenAnswer: A
11) A linear piece of viral DNA of 8 kb can be cut with either of two restriction enzymes (X and
Y). These are subjected to electrophoresis and produce the following bands:
3) Red-green color blindness is caused by a sex- linked recessive allele. A color-blind man marries a woman with normal vision whose father was color -blind. What is the probability that they will have a color -blind daughter? What is the probability that their first son will be color-blind? (Note the different wording in the two questions.) Answer: 1⁄4 for each daughter (1⁄2 chance that child will be female x 1⁄2 chance of a
homozygous recessive genotype); 1⁄2 for first son.
46) One of the buffers that contribute to pH stability in human blood is carbonic acid (H 2CO3 ). Carbonic acid is a weak acid that dissociates into a bicarbonate ion (HCO 3- ) and a
hydrogen ion (H+ ). Thus,
E) The genetic makeup of an
individual
27) Beetle pollinators of a particular plant are attracted to its flowersʹ bright orange color. The beetles not only pollinate the flowers, but they mate while inside of the flowers. A mutant version of the plant with red flowers becomes more common with the passage of time. A particular variant of the beetle prefers the red flowers to the orange flowers. Over time, these two beetle variants diverge from each other to such an extent that interbreeding is no longer possible. What kind of speciation has occurred in this example, and what has driven
it?
22) Which of the following statements is true? A) The closer two genes are on a chromosome, the lower the probability that a crossover will occur between them. B) The observed frequency of recombination of two genes that are far apart from each other has a maximum value of 100%. C) All of the traits that Mendel studied D) Linked genes are found on different chromosomes. E) Crossing over occurs during prophase II of meiosis.
seed color, pod shape, flower color, and othersare due to genes linked on the same chromosome.Answer: A
65) In the 1920s Muller discovered that X -rays caused mutation in Drosophila. In a related series of experiments, in the 1940s, Charlotte Auerbach discovered that chemicals nitrogen mustards cereal manufacturer. Why do we test for its ability to induce mutation? A) We worry that it might cause mutation in cereal grain plants. B) We want to make sure that it does not emit radiation. C) We want to be sure that it increases the rate of mutation sufficiently. D) We want to prevent any increase in mutation frequency. E) We worry about its ability to cause infection.
she usedhave a similar effect. A new chemical food additive is developed by aAnswer: D
12) Two genes of a flower, one controlling blue (B) versus white (b) petals and the other controlling round (R) versus oval (r) stamens, are linked and are 10 map units apart. You cross a homozygous blue-oval plant with a homozygous white -round plant. The resulting F1 progeny are crossed with homozygous white-oval plants, and 1,000 F2 progeny are obtained. How many F2 plants of each of the four phenotypes do you expect? Answer: 450 each of blue-oval and white-round (parentals) and 50 each of blue-round and
white-oval (recombinants)
(B) The solution outside is hypotonic. It has less sucrose, which is a nonpenetrating solute. (C) See answer for A. (D) The artificial cell will become more turgid. (E) Eventually, the two solutions will have the same solute concentrations. Even though sucrose canʹt reach the same concentration on each side, water flow (osmosis)
will lead to isotonic conditions
