Biology 1406 0502 tests 1B, 2A, 3A, 4A answers
Which of the groups shown in Figure 3.4 is a functional group that helps stabilize proteins by forming covalent cross-linkswithin or between protein molecules?
- SH
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?
-20 kcal/mol
Starting with citrate, which of the following combinations of products would result from three acetyl CoA molecules entering the citric acid cycle (see Figure 7.1)?
3 ATP, 6 CO2, 9 NADH, and 3 FADH2
Which of the sequences below best describes the sequential steps (numbered 1-5) in a signal transduction pathway that utilizes a G protein-coupled receptor? 1. The signal-receptor complex activates a G protein. 2. Protein kinases are activated. 3. A signal molecule binds to a receptor. 4. Target proteins are phosphorylated. 5. cAMP is produced.
3, 1, 5, 2, 4
Quaking aspen trees usually reproduce by extending underground stems that then push aboveground and grow into trees. Sexual reproduction is not as common, but when it does happen, the haploid gametes have 19 chromosomes. How many chromosomes are in the cells of the underground stems?
38
When Mendel set up a Parental (P) cross between true breeding purple and white flowered plants to generate the F1 and then allowed the F1 to self-pollinate to generate the F2 he saw a dominant to recessive ratio of 3:1. What phenotypic ratio would be expected if he crossed the F1 with the original purple parent?
4:0
What is the likelihood that the progeny of IV-3 and IV-4 will have the trait?
50%
How many unique gametes could be produced through independent assortment by an individual with the genotype AaBbCCDdEE?
8
In a diploid cell with four chromosome pairs (2n = 8), how many centromeres will be found in a nucleus at G2 of the cell division cycle?
8
The atomic number of nitrogen is 7. Nitrogen-15 is heavier than nitrogen-14 because the atomic nucleus of nitrogen-15 contains how many neutrons?
8
Which of the following graphs most likely describes the effect of pH on the function of the enzyme catalase in human cells? Note: The x-axis is pH and the y-axis is enzyme activity.
A
Which of the following statements correctly describes the terms monohybrid cross and dihybrid cross?
A dihybrid cross involves organisms that are heterozygous for two characters that are being studied, and a monohybrid cross involves organisms that are heterozygous for only one character being studied.
What are the products of linear electron flow during the light reactions of photosynthesis?
ATP and NADPH
Which of the following is the most correct interpretation of the figure?
ATP is a molecule that acts as an intermediary to store energy for cellular work.
Which of the following represents the activation energy required for the enzyme-catalyzed reaction in Figure 6.4?
B
In presenting data that result from an experiment, a group of students show that most of their measurements fall on a straight diagonal line on their graph. However, two of their data points are "outliers" and fall far to one side of the expected relationship. What should they do?
Show all results obtained and then try to explore the reason(s) for these outliers.
Two different species of protists living in a tide pool. Species A reproduces both sexually and asexually, and Species B reproduce only asexually. The pool gradually becomes infested with disease-causing viruses. Which species are more likely to survive in the changing environment?
Species A only
What will happen to a red blood cell (RBC), which has an internal ion content of about 0.9%, if it is placed into a beaker of pure water?
The cell would swell because the water in the beaker is hypotonic relative to the cytoplasm of the RBC.
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?
The decrease in entropy is associated with growth of an organism. As a consequence of growth, organisms cause a greater increase in entropy in their environment than the decrease in entropy associated with their increased complexity.
Which of the following statements is a reasonable explanation for why unsaturated fatty acids help keep a membrane more fluid at lower temperatures?
The double bonds form kinks in the fatty acid tails, preventing adjacent lipids from packing tightly.
What happens to a glucose molecule when it loses a hydrogen atom as the result of an oxidation-reduction reaction?
The glucose molecule is oxidized.
A beaker contains 100 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?
The pH of the beaker's contents will decrease.
How do phospholipids interact with water molecules?
The polar heads interact with water; the nonpolar tails do not.
In a life cycle such as that shown in part III of Figure 10.1, if the zygote's chromosome number is 10, which of the following will be true?
The sporophyte's chromosome number per cell is 10 and the gametophyte's is 5.
Which of the following statements is true for a system at chemical equilibrium?
The system can do no work.
Which of the following conditions is required for a target organ to respond to a particular hormone?
The target organ must have receptors that recognize and bind the hormone molecule.
Cell membranes have distinct inside and outside faces. Which of the following statements is the most likely explanation for the membrane's asymmetrical nature?
The two sides of a cell membrane face different environments and carry out different functions.
How does a scientific theory differ from a scientific hypothesis?
Theories are usually an explanation for a more general phenomenon; hypotheses typically address more specific issues.
What is the relationship between the following two molecules?
They are geometrical isomers.
Which of the following statements best describes homologous chromosomes?
They carry information for the same traits.
In what way are elements in the same column of the periodic table the same?
They have the same number of electrons in their valence shell.
Which of the following statements is true about buffer solutions?
They maintain a relatively constant pH when either acids or bases are added to them.
which of the following statements is true about buffer solutions?
They maintain a relatively constant pH when either acids or bases are added to them.
Which of the following sentences state a significant conclusion that Gregor Mendel drew from his experiments with pea plants?
Traits are inherited in discrete units and are not the result of "blending."
Which of the following statements correctly describes how Mendel explained why traits disappeared in the F1 generation and then reappeared in the F2 generation?
Traits can be dominant or recessive, and the recessive traits were "hidden" by the dominant ones in the F1.
Exposing inner mitochondrial membranes to ultrasonic vibrations will disrupt the membranes. However, the fragments will reseal "inside out." The little vesicles that result can still transfer electrons from NADH to oxygen and synthesize ATP. After the disruption, which components involved in oxidative phosphorylation must be present for electron transfer and ATP synthesis to still occur?
all of the electron transport system and ATP synthase
An obstetrician knows that her patient's 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?
amniocentesis or CVS
A series of enzymes catalyze the reaction X → Y → Z → A. Product A binds to the enzyme that converts X to Y at a position remote from its active site. This binding decreases the activity of the enzyme. 38) With respect to the enzyme that converts X to Y, substance A functions as
an allosteric inhibitor.
In which phase of mitosis do the sister chromatids become daughter chromosomes?
anaphase
During which of the following phases of meiosis do centromeres split and sister chromatids migrate to opposite poles of the cell?
anaphase II
The figure shows the structures of glucose and fructose. Which of the following describes a difference between the two molecules?
arrangement of carbon, hydrogen, and oxygen atoms
Use the following pedigree (Figure 11.3) for a family in which dark-shaded symbols represent individuals with one of the two major types of colon cancer. Numbers under the symbols are the individual's age at the time of diagnosis. From this pedigree, how does this trait seem to be inherited?
as an autosomal dominant
A flask containing photosynthetic green algae and a control flask containing water with no algae are both placed under a bank of lights that is set to cycle between 12 hours of light and 12 hours of dark. The dissolved oxygen concentrations in both flasks are monitored. Predict what the relative dissolved oxygen concentrations will be in the flask with algae compared to the control flask. The dissolved oxygen in the flask with algae will ________.
be higher in the light, but lower in the dark
Which of the following statements describes an example of cooperativity associated with enzyme regulation?
binding a substrate to one subunit of a tetramer stimulates faster binding of substrate to each of the other three subunits
A gardener is concerned that her greenhouse is getting too hot from too much light, and seeks to shade her plants with colored translucent plastic sheets, the color of which allows passage of only that wavelength. What color should she use to reduce overall light energy, but still maximize plant growth?
blue
Starch is composed of ________.
branched amylopectin and unbranched amylose
How does a noncompetitive inhibitor decrease the rate of an enzyme-catalyzed reaction?
by binding to an allosteric site, thus changing the shape of the active site of the enzyme
About 25 of the 92 natural elements are known to be essential to life. Which 4 of these 25 elements make up approximately96% of living matter?
carbon, hydrogen, nitrogen, oxygen
Which two functional groups are always found in amino acids?
carboxyl and amino groups
Beta oxidation generates substrates for cellular respiration through which of the following processes?
catabolism of fatty acids
An animal cell lacking carbohydrates on the external surface of its plasma membrane would likely be impaired in which function?
cell-cell recognition
Organisms interact with their environments, exchanging matter and energy. For example, plant chloroplasts convert the energy of sunlight to
chemical energy.
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, whereas organelles in the lighter fraction could produce ATP in the dark. The heavier and lighter fractions are most likely to contain, respectively,
chloroplasts and mitochondria.
Taxol is an anticancer drug extracted from the Pacific yew tree. In animal cells, Taxol prevents microtubule depolymerization, which interferes with which of the following processes?
chromosome separation
Which of the following conditions may be overcome by increasing the substrate concentration in an enzymatic reaction with a fixed amount of enzyme?
competitive inhibition
The phosphate transport system in bacteria imports phosphate into the cell even when the concentration of phosphate outside the cell is much lower than the cytoplasmic phosphate concentration. Phosphate import depends on a pH gradient across the membrane—more acidic outside the cell than inside the cell. In this bacterial cell, phosphate transport is an example of ________.
cotransport
The synthesis of ATP by oxidative phosphorylation, using the energy released by movement of protons across the membrane down their electrochemical gradient, is an example of which of the following processes?
coupling of an endergonic reaction to an exergonic reaction
Which of the following molecules is synthesized at specific times during the cell cycle and forms an active complex with a kinase?
cyclin
Cooking oil and gasoline (a hydrocarbon) are not amphipathic molecules because they ________.
do not have a polar or charged region
An organism has been isolated from decomposing organic matter. This organism has a cell wall but no chloroplasts. How would you classify this organism?
domain Eukarya, kingdom Fungi
Which of the following factors determines whether a carbon atom's covalent bonds with other atoms are in a tetrahedral configuration or a planar configuration?
double bonds between the carbon atom and other atoms
Van der Waals interactions result when
electrons are not symmetrically distributed in a molecule.
A chemical reaction that has a positive ΔG is best described as ________.
endergonic
A characteristic 9 + 2 arrangement of microtubules, consisting of nine doublets of microtubules surrounding a pair of single microtubules is associated with ________.
eukaryotic flagella and motile cilia
Which of the following terms best describes the forward reaction in Figure 6.4?
exergonic, ∆G < 0
Many diploid organisms produce haploid gametes for reproduction. Which of the following best describes how the diploid number of chromosomes is restored in the offspring of these organisms?
fertilization combines chromosomes from each parent into resulting zygote
Which of the following is not a polymer?
glucose
Which of the following sequences describes the path by which electrons travel downhill energetically in aerobic respiration?
glucose → NADH → electron transport chain → oxygen
Which of the following explains why the valency of carbon is 4 even though it has 6 electrons?
has 2 electrons in its first shell and 4 in the second shell
Cystic fibrosis is a genetic disease in humans in which the CFTR protein, which functions as a chloride ion channel, is missing or nonfunctional in cell membranes. The CFTR protein belongs to what category of membrane proteins?
hydrophilic channels
In which reactions of cellular respiration and fermentation does substrate-level phosphorylation occur?
in both glycolysis and the citric acid cycle
During which of the following processes does independent assortment of chromosomes occur?
in meiosis I only
Which of the following statements correctly describes osmosis?
in osmosis, water moves across a membrane from areas of lower solute concentration to areas of higher solute concentration.
Diffusion of ions across membranes through specific ion channels is driven by ________.
ion electrochemical gradients
According to the fluid mosaic model, a membrane ________.
is composed of a fluid bilayer of phospholipids with embedded amphipathic proteins
The solutions in the two arms of this U-tube are separated by a membrane that is permeable to water and glucose but not to sucrose. Side A is half-filled with a solution of 2 M sucrose and 1 M glucose. Side B is half-filled with 1 M sucrose and 2 M glucose. Initially, the liquid levels on both sides are equal. 49) Initially, in terms of tonicity, the solution in side A with respect to that in side B is
isotonic
Why is glycolysis considered to be one of the first metabolic pathways to have evolved?
it does not involve organelles or specialized structures, does not require oxygen, and is present in most organisms.
In addition to activating or inhibiting enzymes through allosteric regulation, what other means does a cell use to control enzymatic activity?
localization of enzymes into specific organelles or membranes
In a human karyotype, chromosomes are arranged in 23 pairs. If one of the autosomal pairs is examined, which of the following characteristics will the two chromosomes of the pair have in common?
loci and staining pattern
A bacterium engulfed by a white blood cell through phagocytosis will be digested by enzymes contained in ________.
lysosomes
Asbestos is a material that was once used extensively in construction. One risk from working in a building that contains asbestos is the development of asbestosis caused by the inhalation of asbestos fibers. Cells will take up asbestos by phagocytosis, but are not able to degrade it. As a result, asbestos fibers accumulate in ________.
lysosomes
Which of the following macromolecules leave the nucleus of a eukaryotic cell through pores in the nuclear membrane?
mRNA
if two molecules of the general type shown in Figure 3.7 were linked together, carbon-1 of one molecule to carbon-4 of the other, the single molecule that would result would be
maltose
The voltage across a membrane is called the ________.
membrane potential
f one strand of a DNA molecule has the sequence of bases 5′-ATTGCA-3′, the mRNA synthesized following the template will be ________.
mitochondria and chloroplasts.
A sodium-potassium pump ________.
moves three sodium ions out of a cell and two potassium ions into a cell using energy from ATP hydrolysis
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
natural selection
When two atoms are equally electronegative, they will interact to form
non-polar covalent bonds
If yeast cells of mating type α with normal mating factor receptors are genetically modified to produce only mating factor a, they will mate with which of the following cells?
only with each other
The results from Stanley Miller's 1953 experiments can best be used to support which of the following hypotheses?
organic molecules can be synthesized abiotically under conditions that may have existed on early Earth
The mechanism of photophosphorylation is most similar to which of the following processes?
oxidative phosphorylation in cellular respiration
White blood cells engulf bacteria using ________.
phagocytosis
Which of the following structures form cytoplasmic channels that connect adjacent plant cells through the cell walls?
plasmodesmata
localized group of organisms that belong to the same species is called a
population
What makes lipids/fats hydrophobic?
presence of relatively nonpolar C—H bonds
You disrupt all hydrogen bonds in a protein. What level of structure will be preserved?
primary structure
Use the following information to answer the question below.Approximately 32 different monomeric carbohydrate subunits are found in various natural polysaccharides. Proteins are composed of 20 different amino acids. DNA and RNA are each synthesized from four nucleotides.Which class of biological polymer has the greatest functional variety?
proteins
Which of the following frequently imposes a limit on cell size?
ratios of surface area to volume
Activation of which of the following molecules generally requires protein phosphorylation?
receptor tyrosine kinases
Which of the following signal transduction proteins are activated by phosphorylation after binding to a signal molecule?
receptor tyrosine kinases
Which of the following signal transduction proteins typically functions by forming dimers after binding to a signal molecule?
receptor tyrosine kinases
Which of the following are found in plant, animal, and bacterial cells?
ribosomes
What did Engelmann conclude about the congregation of bacteria in the red and blue areas?
Bacteria congregated in these areas because these areas had the most oxygen being released.
Which of the following provides the information necessary to stipulate a protein's 3-D shape?
sequence of amino acids in the polypeptide chain
Which of the following statements describes a key component of the induced fit hypothesis of enzyme catalysis?
Binding of substrate to the active site changes the shape of the active site of an enzyme
After DNA replication, each duplicated chromosome consists of two of which of the following structures?
sister chromatids
Which of the following are least likely to diffuse through the phospholipid bilayer of a cell membrane?
small ions
At which bond would water need to be added to achieve hydrolysis of the peptide, back to its component amino acids?
C
Which of the life cycles is (are) typical for plants and some algae?
C
The unlettered circle at the top of Figure 9.1 shows a diploid nucleus with four chromosomes that have not yet replicated. There are two pairs of homologous chromosomes, one long and the other short. One haploid set is black, and the other is gray. The circles labeled A—E show various combinations of these chromosomes. What is the correct chromosomal condition for one daughter nucleus at telophase of mitosis?
E
Which of the following statements is true of a species that has a chromosome number of 2n = 16?
Each diploid cell has eight homologous pairs of chromosomes.
A (hypothetical) diploid organism has different genes that control wing color and wing length. A female of this species has a paternal chromosome set containing one orange-wing allele and one long-wing allele and a maternal set containing one blue-wing allele and one short-wing allele. Which of the following types of eggs would she be expected to produce after meiosis?
Each egg has a one-fourth chance of having either blue long, blue short, orange long, or orange short combinations.
Which of the following most accurately describes what is happening along the electron transport chain in Figure 7.2?
Each electron carrier alternates between being reduced and being oxidized.
Nitrogen (N) is much more electronegative than hydrogen (H). Which of the following statements is correct about the atoms in ammonia (NH3)?
Each hydrogen atom has a partial positive charge; the nitrogen atom has a partial negative charge.
Which of the following is a major difference between prokaryotic cells and eukaryotic cells?
Eukaryotic cells have membrane-bound organelles, while prokaryotic cells do not.
Imagine there is a species-specific fishing regulation that mandates only adult fish of this species that are 75 cm or longer may be kept and shorter fish must be released. Based on your knowledge of natural selection, you would predict that the average length of the adult fish population will
Gradually Decline
Which of the following sequences correctly represents the flow of electrons during photosynthesis?
H2O → NADPH → Calvin cycle
Human civilizations developed practices regarding inheritance before the scientific grounding of the practices had been determined. Which of the following genetic principles provides scientific support for the societal taboo against closely related people having children?
Heterozygous loci can mask harmful traits in an individual.
Nucleotides can be radiolabeled before they are incorporated into newly forming DNA and can therefore be assayed to track their incorporation. In a set of experiments, a student—faculty research team used labeled T nucleotides and introduced these into the culture of dividing human cells at specific times. Which of the following questions might be answered by such a method?
How many cells are produced by the culture per hour?
Which of these is an example of inductive reasoning?
Hundreds of individuals of a species have been observed and all are photosynthetic; therefore, the species is photosynthetic.
Why do hydrolysis reactions occur more readily in solution than dehydration reactions?
Hydrolysis reactions are exergonic and increase entropy of the system.
At which point in the accompanying figure does MPF reach its highest activity during the cell division cycle?
III
In a high school laboratory, which of the following constitutes an experiment? I. learning to use a microscope by examining fixed specimens on slides II. being able to examine swimming protists under a microscope III. seeking to identify the pigments present in a leaf IV. preparing root tips for examination by staining them
III only
If an animal cell suddenly loses the ability to produce GTP, what will most likely happen to its signaling system?
It will not be able to activate G proteins on the cytoplasmic side of the plasma membrane.
An atom with atomic number 12 would have what type of chemical behavior in bonding with other elements?
It would form ions with a +2 charge.
The oxygen released by photosynthesis is produced by which of the following processes?
splitting water molecules
In mitochondria, an electron transport chain pumps protons from the matrix into the intermembrane space, whereas in chloroplasts, an electron transport chain pumps protons from the ________.
stroma to the thylakoid space
The two molecules shown in Figure 3.1 are best described as
structural isomers.
A cell with a predominance of smooth endoplasmic reticulum is likely specialized to ________.
synthesize large quantities of lipids
ATP is necessary for life because ________.
t is the principle energy carrying molecule in a cell
What is the name of the region on duplicated chromosomes where the sister chromatids are most closely attached to each other?
the centromere
If a solution has a pH of 7, this means that
the concentration of H+ ions in the water equals the concentration of OH- ions in the water.
If the cytoplasm of a cell is at pH 7, and the mitochondrial matrix is at pH 8, this means that
the concentration of H+ ions is tenfold higher in the cytoplasm than in the mitochondrial matrix.
Tay-Sachs disease is a human genetic abnormality that results in cells accumulating and becoming clogged with very large, complex, undigested lipids. Which cellular organelle is most likely defective in this condition?
the lysosome
The difference between an aldose sugar and a ketose sugar is ________.
the position of the carbonyl group
Independent assortment of chromosomes is a result of which of the following processes?
the random way each pair of homologous chromosomes lines up at the metaphase plate during meiosis I
Which of the following statements best describes why phosphorylation cascades are useful in cellular signal transduction?
they amplify the original signal many times
Use the following information when answering the following question.In 1668, Francesco Redi performed a series of experiments on spontaneous generation. He began by putting similar pieces of meat into eight identical jars. Four jars were left open to the air, and four were sealed. He then did the same experiment with one variation: Instead of sealing four of the jars completely, he covered them with gauze (the gauze excluded the flieswhile allowing the meat to be exposed to air). In both experiments, he monitored the jars and recorded whether or not maggots (young flies) appeared in the meat.What hypothesis was being tested in the initial experiment with open versus sealed jars?
Maggots do not arise spontaneously, but from eggs laid by adult flies.
Which of the following statements correctly explains the observation that parents with two different phenotypes produced offspring with a phenotype that is a blend of the two parental varieties?
Neither of the parental alleles is dominant over the other.
Which of the following statements best explains why testosterone, a lipid-soluble signaling molecule that crosses the membranes of all cells, affects only target cells?
Only target cells contain the intracellular receptors for testosterone.
A phospholipid bilayer with equal amounts of saturated and unsaturated fatty acids displays a specific permeability to glucose. What effect will increasing the proportion of unsaturated fatty acids in the bilayer have on the membrane's permeability to glucose?
Permeability to glucose will increase.
Phenylketonuria (PKU) is a recessive human disorder in which an individual cannot appropriately break down the amino acid phenylalanine. This amino acid is not naturally produced by humans. Which of the following treatments would be most effective for people with PKU?
Regulate the individual's diet to severely limit the uptake of phenylalanine.
Genetic variation leads to genetic diversity in populations and is the raw material for evolution. Which of the following statements best represents the connection between reproduction and evolution?
Sexual reproduction increases genetic variation because random mutations can be shuffled between organisms.
There is a group of invertebrate animals called rotifers, among which a particular group of species reproduces, as far as is known, only asexually. These rotifers, however, have survived a long evolutionary history without evidence of having been overcome by excessive mutations. How is natural selection related to sexual reproduction as opposed to asexual reproduction?
Sexual reproduction results in many new gene combinations, some of which will lead to differential reproduction.
Which of the following statements best describes the relationship between photosynthesis and cellular respiration?
Photosynthesis stores energy in complex organic molecules; cellular respiration releases energy from complex organic molecules.
Which of the following statements best describes how cytokinesis differs between plant and animal cells?
Plant cells deposit vesicles containing cell wall building blocks on the metaphase plate; animal cells form a cleavage furrow.
Which of the following relationships among alleles of a single gene best explains the observation that a single change in the gene encoding α-keratin results in chickens with frizzled feathers, increased food consumption, higher heart rate and delayed sexual maturity?
Pleiotropy
Which of the following statements best describes an aspect of signal transduction?
Protein kinase A activation is one possible result of signal molecules binding to G protein-coupled receptors.
If 14C-labeled uracil is added to the growth medium of cells, what macromolecules will be labeled?
RNA
Which molecule is the final electron acceptor for electrons from photosystem I?
NADP+
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?
1
In a particular plant, leaf color is controlled by gene locus D. Plants with at least one allele D have dark green leaves, and plants with the homozygous recessive dd genotype have light green leaves. A true-breeding dark-leaved plant is crossed with a light-leaved one, and the F1 offspring is allowed to self-pollinate. The predicted outcome of the F2 is diagrammed in the Punnett square shown in Figure 11.1, where 1, 2, 3, and 4 represent the genotypes corresponding to each box within the square Which of the boxes marked 1—4 correspond(s) to plants with dark leaves?
1, 2, and 3
Albinism is a recessive trait where an individual does not produce the pigment melanin. A man and woman both produce melanin, but both have one parent with albinism. What is the probability that their first child will have albinism?
1/4
In a cross of individuals who both possess this genotype, AaBbCc, what proportion of the offspring is predicted to have the genotype, AABBCC?
1/64
What is the hydrogen ion (H+) concentration of a solution of pH 8?
10^-8 M
How many molecules of water are released during the polymerization of a 20 monomer-long cellulose molecule?
19
Starting with one molecule of glucose, glycolysis results in the net production of which of the following sets of energy-containing products?
2 NADH, 2 pyruvate, and 2 ATP
Which of the following events accompanies absorption of energy by chlorophyll molecules of the reaction-center complex?
An electron is excited.
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?
Archaea
Which of the following statements best describes density-dependent inhibition?
As cells become more numerous, the cell surface proteins of one cell contact the adjoining cells, and they signal each other to stop dividing.
Which of the following statements correctly describes a distinction between autotrophs and heterotrophs?
Autotrophs, but not heterotrophs, can nourish themselves beginning with CO2 and other nutrients that are inorganic.
What is the difference between covalent bonds and ionic bonds?
Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between atoms.
What is the name of the functional group shown in Figure 3.2?
Carboxyl
Cells from advanced malignant tumors often have very abnormal chromosomes and an abnormal number of chromosomes. Which of the following best explains the association between malignant tumors and chromosomal abnormalities?
Cell cycle checkpoints are not in place to stop cells with chromosome abnormalities.
In what way do the membranes of a eukaryotic cell vary?
Certain proteins are unique to each membrane.
Which of the following results when homologous chromosomes cross over in meiosis?
Corresponding segments of non-sister chromatids are exchanged.
Students conducted an experiment to determine the effect of light intensity on the rate of photosynthesis. They punched 40 leaf disks from spinach leaves and used a syringe partially filled with water to pull the gases from the leaf disks so that all leaf disks sunk to the bottom of the syringe. Ten leaf disks from the syringe were placed in each of four cups and covered with 50 ml of the solutions as indicated below. All leaf disks were resting on the bottom of the cups when the experiment began. The volume of liquid in each cup and the temperature of the solutions were held constant. All cups were placed 0.5 meters from the designated light source. A large beaker of water was placed between the light and the cups to act as a heat sink to prevent a change in temperature. At the end of 10 minutes, the number of disks floating in each cup was recorded. Use your knowledge of the mechanism of photosynthesis and the data presented in the chart to determine which of the statements is a correct explanation for the students' data.
Cup 4 had the lowest rate of photosynthesis because it had the least CO2.
You have just sequenced a new protein found in mice and observe that sulfur-containing cysteine residues occur at regular intervals. What is the significance of this finding?
Cysteine residues are involved in disulfide bridges that help form tertiary structure.
Eukaryotic chromatin is composed of which of the following macromolecules?
DNA and proteins
Which of the following statements about the law of segregation is correct?
It describes the inheritance of different chromosomes relative to one another.
Which of the following statements describes a characteristic feature of a carrier protein in a plasma membrane?
It exhibits specificity for a particular type of molecule.
Which of the following statements best describes the addition rule of probability?
It is the probability that either one of two independent events will occur.
Which of the following characteristics would be most important for a chemotherapeutic drug designed to treat cancer cells?
It specifically inhibits the cell division cycle in rapidly dividing cells.
Which of the following statements is true of metabolism in its entirety in all organisms?
Metabolism consists of all the energy transformation reactions in an organism.
Which of the following statements is true regarding the molecule illustrated in Figure 3.9?
Molecules of this type are usually liquid at room temperature.
In Figure 6.2, why does the reaction rate plateau at higher reactant concentrations?
Most enzyme molecules are occupied by substrate at high reactant concentrations.
Which of the following statements about the cytoskeleton is true?
Movement of cilia and flagella is the result of motor proteins causing microtubules to move relative to each other.
Following glycolysis and the citric acid cycle, but before the electron transport chain and oxidative phosphorylation, the carbon skeleton of glucose has been broken down to CO2 with some net gain of ATP. Most of the energy from the original glucose molecule at that point in the process, however, is stored in the form of which of the following molecules?
NADH
Which of the following statements best describes how steroid hormones access their receptors within target cells?
Steroid hormones are lipid soluble, so they can readily diffuse through the lipid bilayer of the cell and nuclear membranes.
Succinate dehydrogenase catalyzes the conversion of succinate to fumarate. The reaction is inhibited by malonic acid, which resembles succinate but cannot be acted upon by succinate dehydrogenase. Increasing the ratio of succinate to malonic acid reduces the inhibitory effect of malonic acid. 37) Based on this information, which of the following is correct?
Succinate is the substrate, and fumarate is the product.
To identify the molecule that accepts CO2, Calvin and Benson manipulated the carbon-fixation cycle by either cutting off CO2 or cutting off light from cultures of photosynthetic algae. They then measured the concentrations of various metabolites immediately following the manipulation. How would these experiments help identify the CO2 acceptor? Study Figure 8.2 to help you in determining the correct answer.
The CO2 acceptor concentration would increase when the CO2 is cut off, but decrease when the light is cut off.
Which of the following statements best describes the effect of a mutation that knocks out the GTPase activity of a G protein?
The G protein would always be active.
Theodor W. Engelmann illuminated a filament of algae with light that passed through a prism, thus exposing different segments of algae to different wavelengths of light. He added aerobic bacteria and then noted in which areas the bacteria congregated. He noted that the largest groups were found in the areas illuminated by the red and blue light. 39) If you ran the same experiment without passing light through a prism, what would you predict?
The bacteria would be relatively evenly distributed along the algal filaments.
Which of the following correctly describes any reaction that has reached chemical equilibrium?
The rate of the forward reaction is equal to the rate of the reverse reaction.
Use the following information to answer the question below. The citric acid cycle.If you were to add one of the eight citric acid cycle intermediates to the culture medium of yeast growing in the laboratory, what do you think would happen to the rates of ATP and carbon dioxide production?
The rates of ATP production and carbon dioxide production would both increase.
The nuclear lamina is an array of intermediate filaments that line the inner side of the nuclear membrane. If a chemical treatment caused the lamina to disassemble, what would you expect to be the most likely immediate consequence?
a change in the shape of the nucleus
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. The biologists have turned to you for advice. Which of the following compoundsis most likely to mimic the effects of the hormone?
a compound with the same three-dimensional shape as part of the hormone
A loss of function of Apaf1, the human homologue of ced-4 in nematodes, is most likely to result in which of the following?
a form of cancer in which normal apoptosis fails
Which of the following is an example of potential rather than kinetic energy?
a molecule of glucose
A newly discovered unicellular organism isolated from acidic mine drainage is found to contain a cell wall, a plasma membrane, two flagella, and peroxisomes. Based just on this information, the organism is most likely ________.
a motile eukaryote
A glycosidic linkage is analogous to which of the following in proteins?
a peptide bond
Use the following information to answer the question."The native structure of hemoglobin (Hb) comprises of two α and two β subunits, each of which carries a heme group. There appear to be no previous studies that report the in-vitro folding and assembly of Hb from highly unfolded α and β globin in a 'one-pot' reaction. One difficulty that has to be overcome for studies of this kind is the tendency of Hb to aggregate during refolding. This work demonstrates that denaturation of Hb in 40% acetonitrile at pH 10.0 is reversible." (J Am Soc Mass Spectrum 2007, 18, 8-16)
a quaternary protein with four polypeptides
Which of the following characteristics are part of the sexual life cycle of most fungi but are not part of the sexual life cycles of plants or animals?
a unicellular haploid stage
Liquid water's high specific heat is mainly a consequence of the
absorption and release of heat when hydrogen bonds break and form
A given solution contains 0.0001(10-4) moles of hydrogen ions (H+) per liter. Which of the following best describes this solution?
acidic: will give H+ to weak acids, but accept H+ from strong acids
Feather color in budgies is determined by two different genes, Y for pigment on the outside of the feather, and B for pigment on the inside of the feather. YYBB, YyBB, or YYBb is green; yyBB or yyBb is blue; YYbb or Yybb is yellow; and yybb is white. Two blue budgies were crossed. Over the years, they produced 22 offspring, five of which were white. What are the most likely genotypes for the two blue budgies?
yyBb and yyBb