bio

The number of hydrogen bonds between two molecules affects how much energy is needed to break those two molecules apart. The more hydrogen bonds there are, the more energy that is required. Which of the following base pairs requires the most energy to break apart? A. A-U B. T-A C. G-C D. A-T

C. G-C

What is the name of the enzyme that forms at the start of transcription? A. DNA gyrase B. DNA polymerase C. RNA polymerase D. RNA helicase

C. RNA Polymerase

What does RNA polymerase bind to in order to initiate transcription? A. start codon B. RNA promoter region C. DNA promoter region D. mRNA

C. DNA promoter region

If the first nucleotide after the promoter on the bottom DNA strand is changed from C to T, what would the resulting nucleotide be on the mRNA? U T A C

A

If the first nucleotide after the promoter on the top DNA strand is changed from G to T, what would the resulting nucleotide be on the mRNA? T C G A

A

Which base pairing is incorrect? A-T A-G U-A G-C

A-G

How many hydrogen atoms are present in a hydrocarbon chain of five carbon atoms with one double bond and the rest single bonds? HINT: draw the five carbons connected to one another by covalent bonds and then determine how many additional bonds are possible for each carbon. Remember it's a chain, not a ring. A. 10 B. 12 C. 8 D. 6

A. 10

Which choice ranks the elements hydrogen, carbon, nitrogen, and oxygen in order of decreasing dry mass in living organisms? HINT: Refer to the periodic table. A. C→O→H→N B. O→H→C→N C. C→N →O →H D. O→C→H→N

A. C→O→H→N

Which one of the statements explains a characteristic of both all living organisms and all nonliving material? A. They both conform to the basic laws of chemistry and physics. B. They both have the capacity to evolve. C. They both are complex, with spatial organization at several levels. D. They both have the ability to change in response to the environment. E. They both have the ability to reproduce.

A. They both conform to the basic laws of chemistry and physics.

Which portion of DNA contains the genetic information "read" by the RNA polymerase and transmitted into mRNA? A. base B. phosphodiester bond C. backbone D. sugar

A. base

Most of life's diversity is: A. microbial. B. aquatic. C. terrestrial. D. acellular. E. aerobic.

A. microbial.

Studies of the origin of life on Earth help us to consider what would be required for life elsewhere in the universe. What is most likely to be true of extraterrestrial life if it exists? A. Light from a nearby star will make photosynthesis possible. B. Carbon will act as the backbone for organic molecules. C. Water will not be required to sustain life. D. Oxygen will be used to convert energy in cells.

B. Carbon will act as the backbone for organic molecules.

If a mutation in the middle of the bottom DNA strand results in the coding of a stop codon, the resulting mRNA length would be: A. 16 nucleotides long. B. 24 nucleotides long-a stop codon would not affect the length of the mRNA, only the length of the resulting protein. C. 12 nucleotides long. D. 32 nucleotides long.

B. 24 nucleotides long-a stop codon would not affect the length of the mRNA, only the length of the resulting protein.

The genetic information carried by DNA is in the ___________ and their __________. A. base-pairing; hydrogen bonds B. bases; sequence C. sugars; atoms D. phosphates; phosphodiester bonds

B. bases; sequence

In which of the examples is the entropy definitely increasing? A. photosynthesis B. melting ice in a glass of soda C. making a house of playing cards D. placing marbles in a row

B. melting ice in a glass of soda

If you made a change in the promoter sequence in the DNA, what would happen at the RNA level? A. The DNA helicase would not be able to recognize and bind the DNA, so the RNA would not be made. B. Nothing, the RNA would be made as usual. C. The RNA polymerase would not be able to recognize and bind the DNA, so no RNA would be made. D. The mutation of the DNA would be carried through to the RNA sequence.

C. The RNA polymerase would not be able to recognize and bind the DNA, so no RNA would be made.

Where does transcription of mRNA begin? A. at the 5' end of the gene on the DNA template strand B. at the AUG start codon on the mature mRNA strand C. at the 3' end of the gene on the DNA template strand

C. at the 3' end of the gene on the DNA template strand

When carrying out a controlled experiment, it is important to: A. All of these choices are correct. B. subject different groups to different conditions. C. change only one variable at a time. D. change multiple variables at once to see the full effect of the variables.

C. change only one variable at a time.

Which choice is a pyrimidine found in DNA? A. guanine B. adenine C. thymine D. uracil E. None of the other answer options are correct.

C. thymine

Nucleic acids are important information storage molecules present in virtually every cell. Which of the processes is carried out by a cell when it accesses that information in the DNA of the genes? A. DNA replication and transcription B. DNA replication and translation C. transcription and translation

C. transcription and translation

Several sets of percentage of DNA bases that make up the genome are listed below. Which set is correct? A. A: 30%, T: 40%, G: 20%, C: 10% B. A: 10%, T: 30%, G: 40%, C: 20% C. A: 20%, T: 20%, G: 50%, C: 10% D. A: 30%, T: 30%, G: 20%, C: 20%

D. A: 30%, T: 30%, G: 20%, C: 20%

Consider the image. If the ostrich egg shown in the photo is not fertilized, it is composed of approximately how many cells? A. 100 B. 1,000,000 C. 100,000,000 D. 10,000 E. 1

E. 1

All genes in DNA code for proteins. True False

False

If a molecule can freely cross the membrane, then at equilibrium there will be no further movement of molecules across the membrane. True False

False

Molecules that can move freely across the membrane can also move across the membrane by going through channels True False

False

Simple diffusion of a molecule down its concentration gradient requires an input of energy to the system. True False

False

RNA polymerase reads the DNA 3' to 5' on both the top and bottom DNA strand. True False

True

Which tRNA anticodon sequence is the correct match to the mRNA codon listed below? Note: codon-anticodon base-pairing is antiparallel. 5'-CGA-3' a. 3'-GCU-5' b. 3'-GCT-5' c. 3'-CGA-5' d. 3'-TCG-5'

a. 3'-GCU-5'

For the numbered steps below, select the option that places them in the correct order. 1) The ribosome binds to the mRNA and uses tRNAs to translate mRNA into the corresponding amino acid polypeptide sequence. 2) The spliceosome removes introns. 3) The primary structure of the polypeptide chain undergoes hierarchical foldings to form the tertiary structure. 4) RNA polymerase binds to the promoter region of a gene and initiates transcription. a. 4 > 2 > 1 > 3 b. 2 > 1 > 4 > 3 c. 3 > 1 > 4 > 2 d. 1 > 2 > 3 > 4

a. 4 > 2 > 1 > 3

Shown here is a portion of the final mRNA sequence. Which sequence is from the corresponding DNA template strand? mRNA 5'-CCAUGUUCGAAUGGCUUG-3' a. 5'-CAAGCCATTCGAACATGG-5' b. 5'-CAAGCCAUUCGAACAUGG-5' c. 5'-CCAUGUUCGAAUGGCUUG-3' d. 5'-CCATGTTCGAATGGCTTG-3'

a. 5'-CAAGCCATTCGAACATGG-5'

What is the difference between a gene and an allele? a. A gene is a segment of DNA that codes for a protein or RNA; alleles are alternate forms of a gene. b. A gene is a segment of DNA that codes for a protein or RNA; the term allele refers to all of the DNA in a cell or organism. c. An allele is a segment of DNA that codes for a gene; genes are alternate forms of an allele. d. An allele is a segment of DNA that codes for a protein or RNA; genes are alternate forms of an allele.

a. A gene is a segment of DNA that codes for a protein or RNA; alleles are alternate forms of a gene.

What is the result of DNA ligase's action? a. DNA fragments are joined together. b. DNA is broken up at specific sites. c. DNA is condensed to chromosomes. d. DNA transcription occurs. e. DNA translation occurs.

a. DNA fragments are joined together.

What is the difference between mismatch repair and nucleotide excision repair? a. In mismatch repair, one nucleotide is replaced, whereas in nucleotide excision repair several nucleotides are replaced. b. In mismatch repair, several nucleotides are replaced, whereas in nucleotide excision repair the sugar phosphate backbone is fixed. c. In mismatch repair, the sugar phosphate backbone is fixed, whereas in nucleotide excision repair, several nucleotides are replaced. d. In mismatch repair, several nucleotides are replaced, whereas in nucleotide excision repair just one nucleotide is replaced.

a. In mismatch repair, one nucleotide is replaced, whereas in nucleotide excision repair several nucleotides are replaced.

Which mutations in an animal somatic cell are inherited by the next generation? a. None of the other answer options is correct. b. point mutations c. deletions d. synonymous mutations

a. None of the other answer options is correct.

Which of the statements about the strands of a newly replicated DNA molecule is correct? a. One strand is new, and the other is from the original molecule. b. The base pairs are conserved, and new sugar-phosphate backbones are built up on them. c. Both strands are made up of newly assembled nucleotides. d. Both strands contain some nucleotides from the original molecule. e. The sugar-phosphate chains are conserved, and new bases are inserted between them.

a. One strand is new, and the other is from the original molecule.

The Δ32 allele of the CCR5 receptor protein implicated in long-term HIV survival has which of these properties? a. The Δ32 allele makes it more difficult for HIV to infect its target cells. b. The Δ32 allele reduces the number of HIV particles that come out of target cells. c. The Δ32 allele makes it more difficult to be exposed to HIV. d. The Δ32 allele makes it more difficult for HIV to replicate inside target cells.

a. The Δ32 allele makes it more difficult for HIV to infect its target cells.

Which components make up the ribosome? Select all that apply. carbohydrate protein DNA RNA

protein and RNA

The ligand for a G protein-coupled receptor is added to cells, but they exhibit no cellular response. After some tests, you identify ATP levels are lower than normal but GTP levels are not lower than normal. Which process(es) are likely to be affected by this? Select all that apply. a. activation of protein kinase A b. activation of G protein c. activation of G protein-coupled receptor d. activation of adenylyl cyclase

a. activation of protein kinase A d. activation of adenylyl cyclase

Which of the choices is an example of potential energy? a. an electrochemical gradient across the cell membrane b. chemical transport, as in the sodium-potassium pump c. contraction of a muscle cell d. flow of calcium ions through a membrane channel

a. an electrochemical gradient across the cell membrane

Which stages of mitosis are correctly matched with the events that occur in the stage? Select all that apply. a. cytokinesis; a contractile ring of actin filaments forms at the cell equator b. anaphase; chromosomes start to condense c. metaphase; chromosomes line up in the middle of the cell d. prometaphase; nuclear envelope reforms e. telophase; nuclear envelope breaks down

a. cytokinesis; a contractile ring of actin filaments forms at the cell equator c. metaphase; chromosomes line up in the middle of the cell

The majority of the energy captured in the citric acid cycle is in the form of: a. electrons donated to NAD+ and FAD. b. ATP produced by oxidative phosphorylation. c. ATP produced by substrate-level phosphorylation. d. GTP produced by substrate-level phosphorylation. e. GTP produced by oxidative phosphorylation.

a. electrons donated to NAD+ and FAD.

Molecules that are _____________ and _____________ are able to move across the cell membrane via simple diffusion. a. hydrophobic; small b. hydrophilic; small c. hydrophobic; large d. hydrophilic; large

a. hydrophobic; small

In normal meiosis, when do homologous chromosomes separate from each other? a. in the first meiotic division b. They may separate in either the first or second meiotic divisions. c. in the second meiotic division

a. in the first meiotic division

Cellular responses that result from receptor kinase activation tend to: a. involve changes in gene expression. b. involve changes in metabolism. c. involve ion channels. d. be short term.

a. involve changes in gene expression.

Which cytoskeleton component plays a major role in the formation of the mitotic spindle? a. microtubules b. microfilaments c. intermediate filaments

a. microtubules

The oxidation of pyruvate occurs in the: a. mitochondrial matrix. b. mitochondrial intermembrane space. c. stroma. d. lumen of the thylakoid. e. cytoplasm.

a. mitochondrial matrix.

The terminal electron acceptor of a mitochondrial electron transport chain is: a. oxygen b. NAD+. c. water. d. NADPH. e. NADP+

a. oxygen

Which of the choices is not needed for DNA replication? a. ribosomes b. None of the answer options is correct. c. DNA d. nucleotides e. enzymes

a. ribosomes

What feature of double-stranded DNA makes it necessary to have a leading strand and a lagging strand during replication? a. the antiparallel orientation of the strands b. the hydrogen bonding between bases c. the negative charge on the sugar-phosphate backbone d. the base stacking of the bases

a. the antiparallel orientation of the strands

Which enzyme relieves the tension on the double helix during DNA replication? a. topoisomerase. b. a single-stranded binding protein c. helicase d. an RNA primer d. DNA polymerase

a. topoisomerase.

Of the 6 carbons in a starting molecule of glucose, at the completion of pyruvate oxidation, _____ carbons are fully oxidized to _____, while _____ carbons remain in _____. a. two; CO2; four; acetyl groups b. three; pyruvate; three; acetyl groups c. two; acetyl groups; four; CO2 d. four; acetyl groups; two; CO2 e. four; CO2; two; CoA

a. two; CO2; four; acetyl groups

A new nucleotide can only be added to the _____ end of a growing DNA strand. DNA therefore always grows in the _____ direction. a. 5'; 3' to 5' b. 3'; 5' to 3' c. 5'; 5' to 3' d. 3'; 3' to 5'

b. 3'; 5' to 3'

Which two molecules are produced by the photosynthetic electron transport chain and used in the Calvin cycle? a. CO2, ATP b. ATP, NADPH c. glucose, ATP d. NADH, FADH2 e. water, ATP

b. ATP, NADPH

Carriers can move certain molecules across a membrane. Which of the answer choices is not a property of carriers? a. Some carriers bind a single molecule and others can bind multiple molecules simultaneously. b. Carriers can transfer any molecule as long as it is not larger than the diameter of the carrier. c. Carriers have regions with many hydrophobic amino acids. d. Carriers have high specificity for a single molecule.

b. Carriers can transfer any molecule as long as it is not larger than the diameter of the carrier.

Which of the enzymes is responsible for initiating the proofreading repair mechanism? a. DNA uracil glycosylase b. DNA polymerase c. DNA ligase d. AP endonuclease e. None of the other answer options is correct.

b. DNA polymerase

Which molecule is initially oxidized to provide electrons for the photosynthetic electron transport chain? a. NADH b. H2O c. glucose d. FADH2 e. pyruvate

b. H2O

Imagine that you know two sisters, Rose and Sam, both of whom smoke. Rose has a mutation in the gene for alpha-1 antitrypsin, whereas Sam does not. Which of the statements is true regarding these sisters? a. As both sisters smoke, Rose and Sam will certainly develop emphysema; however, given her mutation, Rose will likely develop a much more serious form of the disease. b. It is possible that neither Rose nor Sam will develop emphysema; however, the fact that both sisters smoke, in addition to the mutation that Rose carries, increases their chances of developing this disease. c. Given that a mutation in alpha-1 antitrypsin serves a "protective" function against the development of emphysema, Rose will not develop this disease but Sam will. d. Rose is predisposed to develop emphysema, but if Sam does, this will be a random occurrence; environmental factors or lifestyle choices, such as smoking, have not been associated with emphysema.

b. It is possible that neither Rose nor Sam will develop emphysema; however, the fact that both sisters smoke, in addition to the mutation that Rose carries, increases their chances of developing this disease.

In the experiment that showed membrane fluidity, what was the purpose of shining a laser on the membrane? a. The laser light makes the proteins fluorescent. b. The laser light destroys the dye fluorescence. c. The laser light allows the dye to be seen with the microscope.

b. The laser light destroys the dye fluorescence.

Predict what happens when both centrosomes of a cell are removed during the prophase stage of mitosis. a. The microtubules of the mitotic spindle attach to the cell membrane instead of the kinetochore of each sister chromatid. b. The mitotic spindle does not form and mitosis does not continue. If the centrosomes are removed during the prophase stage of mitosis, then the mitotic spindle will not form and mitosis does not continue. c. Sister chromatids separate during the metaphase stage of mitosis. d. The cell undergoes cytokinesis early, resulting in the formation of two haploid instead of two diploid cells

b. The mitotic spindle does not form and mitosis does not continue. If the centrosomes are removed during the prophase stage of mitosis, then the mitotic spindle will not form and mitosis does not continue.

Which of the statements concerning cancer and mutations is correct? a. Usually a single mutation is all that is required to cause cancer. b. Usually multiple mutations are required in different genes to cause cancer. c. Cancer can only occur with a mutation in a somatic cell. d. Cancer can only occur with a mutation in a germ cell. e. None of the other answer options is correct.

b. Usually multiple mutations are required in different genes to cause cancer.

Which of the answer choices would be the best analogy for an electrochemical gradient across a cellular membrane? a. a light bulb b. a battery c. a water pump d. an electric generator e. a waterfall

b. a battery

Which of the choices is an example of kinetic energy? a. gasoline in an auto gas tank b. a photon of light c. a ball at the top of stairs d. water behind a dam e. a C-H bond in a sugar molecule

b. a photon of light

The _____ stage of cellular respiration generates the most NADH, which will be used in oxidative phosphorylation to produce _____ (proportion) of the total ATP yield from glucose. a. pyruvate oxidation; 16/32 (1/2) b. citric acid cycle; 15/32 c. glycolysis; 15/32 d. citric acid cycle; 19/32 e. glycolysis; 8/32

b. citric acid cycle; 15/32

A specific ligand is polar in nature. Where is the ligand-binding portion of the receptor most likely to be located? a. cytoplasm of the cell b. extracellular side of the cell membrane c. lumen (interior) of the endoplasmic reticulum d. cytoplasmic side of the cell membrane

b. extracellular side of the cell membrane

The first stage in the production of ATP via the oxidation of glucose molecules is referred to as: a. the Calvin cycle. b. glycolysis. c. The word root 'glyco' is used to refer to sugars, especially glucose, and 'lysis' refers to splitting or cutting. Thus, glycolysis is the breakdown of glucose. d. the electron transport chain. e. the citric acid cycle.photosynthesis.

b. glycolysis.

What enzyme moves outward from the origin of replication and breaks hydrogen bonds between DNA nucleotides? a. DNA polymerase b. helicase c. topoisomerase II d. RNA primase

b. helicase

Which cytoskeleton component plays a major role during cytokinesis? a. intermediate filaments b. microfilaments c. microtubules

b. microfilaments

To move a specific molecule across a membrane, carrier proteins: a. require that different molecules move in the opposite direction from the molecule specific to the carrier. b. require that the molecule specific to the carrier bind and cause a change in conformation. c. require an input of energy to achieve the change in conformation necessary to facilitate movement across the membrane. d. require a steep concentration gradient of the molecule across the membrane.

b. require that the molecule specific to the carrier bind and cause a change in conformation.

The energy required to drive the synthesis of the majority of the ATP generated during aerobic respiration comes most directly from: a. sunlight. b. the flow of protons through an ATP synthase complex. c.the movement of electrons through an electron transport chain. d. removal of a phosphate group from another molecule. e. the conversion of glucose into two molecules of pyruvate.

b. the flow of protons through an ATP synthase complex.

Table sugar can burn in the reaction if ignited: C6H12O6 + 6O2 → 6CO2 + 6H2O and in the process some potential energy of the sugar becomes kinetic energy. Which of the choices represents kinetic energy from this reaction? a. some of the sugar becomes energy b. the products and their surroundings have more heat c. the products are simpler than the starting molecule

b. the products and their surroundings have more heat

The American Cancer Society currently estimates that only about 10% of all people with melanoma have a family history of the disease. What factors might contribute to the development of melanoma in the other 90% of patients? a. exposure to solar radiation b. exposure to chemical mutagens c. All of these choices are correct. d. mutations in a melanocyte

c. All of these choices are correct.

When a single pyruvate is converted to acetyl-CoA during pyruvate oxidation, the other products of the reaction are: a. CO2 and ATP. b. Pi and FADH2. c. CO2 and NADH. d. NADH and ATP. e. FADH2 and ATP.

c. CO2 and NADH.

The enzyme responsible for proofreading a growing DNA strand and for replacing mismatched nucleotides is a. DNA replicase. b. helicase. c. DNA polymerase. d. topoisomerase II. e. DNA ligase.

c. DNA polymerase.

Many cellular processes represent work that requires the expenditure of energy. Which of the actions is not a cellular process that requires the cell to expend energy? a. Synthesis of large biomolecules like proteins and nucleic acids. b. Contraction of muscle cells. c. Diffusion of water into cells. d. Keeping sodium ion concentration lower inside a cell than outside the cell.

c. Diffusion of water into cells.

Which is true? a. Down syndrome is caused by errors in fertilization. b. Down syndrome is the one inherited disorder that results from an extra copy of an entire chromosome. c. Errors in chromosome segregation can occur in either the first or second meiotic division. d. Nondisjunction can only produce gametes with extra chromosomes, not missing chromosomes.

c. Errors in chromosome segregation can occur in either the first or second meiotic division.

Why are some mutations of Ras associated with cancer? a. Ras alters ion flow across the cell membrane. b. Ras is a type of second messenger. c. Ras activates the MAP kinase signal transduction pathway that regulates cell division. d. Ras binds to growth factor receptors.

c. Ras activates the MAP kinase signal transduction pathway that regulates cell division.

What happens if the conversion of GTP into GDP by the G protein is inhibited? a. cAMP molecules are degraded into AMP. b. Phosphatases dephosphorylate the target proteins of protein kinase A. c. The amplification reaction continues until ATP levels are too low. d. Polar ligands stop binding G protein-coupled receptors.

c. The amplification reaction continues until ATP levels are too low.

The sequence for a portion of the DNA template strand and the corresponding mRNA that is being transcribed is shown here. mRNA 5'-GCAGCC-3' DNA template 3'-GCGCGTCGGTACA-5' Which base will the RNA polymerase add next to the growing mRNA molecule? a. thymine b. uracil c. adenine d. guanine e. cytosine

c. adenine

The transition state is that portion of the progress of a chemical reaction with a large amount of energy found in _______ reactions. a. endergonic b. non-spontaneous c. both endergonic and exergonic d. exergonic

c. both endergonic and exergonic

Which kind of damage to DNA can be caused by X-rays? a. cross-links between adjacent pyrimidine bases b. loss of a base from one of the deoxyribose sugars, resulting in a gap in one DNA strand c. breaks in one or both of the sugar-phosphate backbones d. addition of bulky side groups that hinder proper base pairing

c. breaks in one or both of the sugar-phosphate backbones

Which phase of the Calvin cycle does not require ATP? a. regeneration b. reduction c. carboxylation

c. carboxylation

A chemical compound would increase the mutation rate if it inhibited: a. mismatch repair. b. nucleotide excision repair. c. DNA ligase. d. base excision repair. e. All of these choices are correct.

e. All of these choices are correct.

An electron from NADH entering the electron transport chain would travel among components of the chain in what sequence? a. complex I, coenzyme Q, complex II, cytochrome c, complex III, coenzyme Q, complex IV, cytochrome c, oxygen b. complex I, coenzyme Q, complex III, cytochrome c, ATP synthase, oxygen c. complex I, coenzyme Q, complex III, cytochrome c, complex IV, oxygen d. complex II, cytochrome c, complex IV, cytochrome c, oxygen e. complex II, coenzyme Q, complex IV, cytochrome c, ATP synthase, oxygen

c. complex I, coenzyme Q, complex III, cytochrome c, complex IV, oxygen

Which type of reaction is carried out by adenylyl cyclase? a. phosphorylation of GDP into GTP b. phosphorylation of a protein target c. cyclization of ATP into cAMP d.hydrolysis of ATP into ADP

c. cyclization of ATP into cAMP

What is nondisjunction? a. failure of chromosomal replication b. failure of chromosomal pairing c. failure of chromosomal separation d. failure of chromosomal condensation

c. failure of chromosomal separation

These enzymes play important roles in DNA replication: DNA polymerase, primase, ligase, helicase. In what order do they work during replication? a. DNA polymerase, helicase, primase, ligase b. DNA polymerase, primase, ligase, helicase c. helicase, primase, DNA polymerase, ligase d. ligase, helicase, DNA polymerase, primase e. primase, helicase, ligase, DNA polymerase

c. helicase, primase, DNA polymerase, ligase

Which process is carried out by the spliceosome? a. DNA replication b. translation c. intron removal d. transcription e. exon removal

c. intron removal

As molecules move down their concentration gradient, from a more ordered state to a less ordered state, entropy: a. remains the same. b. is decreasing. c. is increasing.

c. is increasing.

A eukaryotic chromosome has _____ origin(s) of replication, and a bacterial chromosome has ______ origin(s) of replication. a. many; many b. one; many c. many; one d. one; one

c. many; one

Which of the statements about mutations is true? a. A mutation: will be corrected. b. will result in a different phenotype. c. may leave the amino acid sequence of a protein unchanged. d. None of the other answer options is correct. e. will be passed on to offspring.

c. may leave the amino acid sequence of a protein unchanged.

Which type of repair is a backup for the DNA polymerase proofreading function? a. nucleotide excision repair b. base excision repair c. mismatch repair d. DNA ligase

c. mismatch repair

In which type of nondisjunction could the two copies of a chromosome in a gamete be heterozygous? a. nondisjunction in the second meiotic division b. Nondisjunction in either meiotic division could produce gametes with two copies of a chromosome that are heterozygous. c. nondisjunction in the first meiotic division

c. nondisjunction in the first meiotic division

A point mutation that causes an amino acid replacement is called a: a. nonsense mutation. b. synonymous (silent) mutation. c. nonsynonymous (missense) mutation. d. transition mutation. e. stop mutation.

c. nonsynonymous (missense) mutation.

A gene that normally has the sequence CAGAGCCTATTAGGC is replicated as CAGAGCTGACGAGGC. Which of the repair mechanisms would most likely be employed to fix this replication error? a. base excision repair and/or nucleotide excision repair b. base excision repair c. nucleotide excision repair d. When damage involves a DNA segment it is repaired by nucleotide excision repair. e. DNA polymerase proofreadingNone of the answer options is correct.

c. nucleotide excision repair

The main mutagenic effects of ultraviolet light are chemical cross-links between adjacent thymines in a DNA strand. These could be repaired by: a. mismatch repair. b. base excision repair. c. nucleotide excision repair. d. DNA replication.

c. nucleotide excision repair.

During the citric acid cycle, the production of CO2 is the result of the _____ of intermediate compounds of the citric acid cycle coupled to the production of _____. a. reduction; NADH b. oxidation; ATP c. oxidation; NADH d. reduction; ATP

c. oxidation; NADH

Which protein level best matches the description "blocks on a string"? a. tertiary b. quaternary c. primary d. secondary

c. primary

The enzyme _____ repairs breaks in the DNA sugar-phosphate backbone. a. uracil glycosylase b. AP endonuclease c. None of the other answer options are correct. d. DNA polymerase e. DNA ligase

e. DNA ligase

At the end of M phase for a single cell, how many daughter cell(s) are present? a. 3 b. 4 c. 1 d. 2

d. 2

For the macromolecules listed here, select the correct order for the proper flow of genetic information. 1) RNA 2) protein 3) DNA a. 2 > 3 > 1 b. 1 > 2 > 3 c. 1 > 3 > 2 d. 3 > 1 > 2

d. 3 > 1 > 2

Consider the steps in activation of a cellular response. I. Protein kinase A is activated. II. Ligand binds to G protein-coupled receptor. III. ATP is converted into cAMP .IV. The alpha subunit of the G protein activates adenylyl cyclase. V. GDP is replaced by GTP in the G protein. In what order do the steps for the activation of a cellular response take place? a. I > III > II > IV > V b. IV > II > V > I > IIII c. II > IV > I > V > II d. II > V > IV > III > I e. V > I > III > II > IV

d. II > V > IV > III > I

Predict what happens if each adenylyl cyclase enzyme is able to convert only one molecule of ATP into cAMP, reducing the amount of cAMP produced. a. Phosphatases are activated to reduce the competition for the target protein of protein kinase A. b. Additional G protein-coupled ligands are expressed to compensate for the reduction in cAMP production. c. Not enough cAMP is generated and the cell undergoes signal termination. d. Not enough molecules of protein kinase A are activated and the cellular response is dampened.

d. Not enough molecules of protein kinase A are activated and the cellular response is dampened.

During prometaphase, the microtubules of the mitotic spindle attach only to the kinetochore of a single sister chromatid and not to the other for the maternal copy of chromosome 21. What will happen to the copy number of chromosome 21 in the resulting daughter cells? a. The two daughter cells are not affected and are equal in chromosome 21 copy number (each has two copies of chromosome 21). b. Both daughter cells have double the normal number of chromosome 21 (four copies each). c. One of the daughter cells is missing both copies of chromosome 21 and the other cell has four copies of chromosome 21. d. One of the daughter cells has trisomy (three copies) of chromosome 21 and the other daughter cell is missing one of the two copies of chromosome 21.

d. One of the daughter cells has trisomy (three copies) of chromosome 21 and the other daughter cell is missing one of the two copies of chromosome 21.

tRNA genes are transcribed by: a. DNA polymerase. b. aminoacyl tRNA synthetase. c. spliceosome. d. RNA polymerase.

d. RNA polymerase.

Which of the factors accounts for the higher potential energy of C-C and C-H bonds compared to C-O and H-O bonds? a. The C-C and C-H bonds are strong, thus requiring a lot of energy to hold together. b. The C-O and H-O bonds are strong, thus requiring a lot of energy to hold together. c. The C-O and H-O bonds are weak, thus requiring less energy to hold together. d. The C-C and C-H bonds are weak, thus requiring a lot of energy to hold together.

d. The C-C and C-H bonds are weak, thus requiring a lot of energy to hold together.

A photon of ultraviolet light hits double-stranded DNA and creates a covalent cross-link between adjacent thymines in the same strand (a thymine dimer). What is likely to happen? a. The DNA strand with the thymine dimer will not be able to be replicated. b. The DNA strand will replicate, but the daughter strand will carry an adenine dimer. c. The cell will die. d. The thymine dimer will be repaired by nucleotide excision repair. e. The cell will divide, but the daughter cells will be mutant.

d. The thymine dimer will be repaired by nucleotide excision repair.

In the citric acid cycle, after the acetyl-group (2C) from acetyl-CoA is transferred to oxaloacetate (4C) to produce citrate (6C), subsequent reactions eventually result in 4C intermediates that are rearranged to regenerate oxaloacetate. What happens to the other two carbons? a. They are recycled into pyruvate. b. They are transferred to NAD+ and FAD. c. They are rearranged into a new acetyl group. d. They are released as CO2 byproducts. e. They become ATP.

d. They are released as CO2 byproducts.

What is the end-result of activating the MAP kinase pathway? a. ion flow b. synthesis of second messenger molecules c. phosphorylation of multiple cytosolic proteins d. a change in gene expression

d. a change in gene expression

an active transport proton pump drives protons out of the cell using energy from ATP. Under some circumstances pumps like this can be run in reverse. If this pump could be reversed, what would be the result in the cytoplasm? a. a decrease in H+ concentration and a decrease in ATP b. an increase in pH and an increase in ATP c. an increase in the electrochemical gradient d. a decrease in pH and an increase in ATP e. an increase in H+ concentration and an increase in ADP

d. a decrease in pH and an increase in ATP

If nondisjunction occurs in the first meiotic division, how many of the four possible gametes produced from meiosis will have the wrong number of chromosomes? a. one b. two c. three d. four

d. four

Protons in a mitochondrion flow through an ATP synthase from the: a. cytoplasm to the intermembrane space. b. intermembrane space to the cytoplasm. c. matrix to the intermembrane space. d. intermembrane space to the matrix

d. intermembrane space to the matrix

In eukaryotes, pyruvate oxidation takes place in the: a. outer mitochondrial membrane. b. intermembrane space of mitochondria. c. inner mitochondrial membrane. d. mitochondrial matrix. e. cytoplasm.

d. mitochondrial matrix.

A point mutation that changes a UAC codon into a UAG codon is a: a. frameshift mutation. b. silent mutation. c. missense mutation. d. nonsense mutation.

d. nonsense mutation.

The citric acid cycle is a cycle because the starting molecule, _____, is regenerated at the end. a. NAD+ b. acetyl-CoA c. pyruvate d. oxaloacetate e. fructose 6-diphosphate

d. oxaloacetate

Which process provides an eventual carbon source for glycolysis? a. pyruvate oxidation b. photosynthesis c. ATP synthesis d. the Calvin cycle

d. the Calvin cycle

Which is the only reaction in the citric acid cycle that produces ATP by substrate-level phosphorylation? a. the formation of malate b. the formation of fumarate c. the formation of oxaloacetate d. the formation of succinate e. the formation of citrate

d. the formation of succinate

Which statement describes the proton gradient generated by the electron transport chain? a. The concentration is highest in the hydrophobic center of the inner membrane. b. It contains a great deal of kinetic energy. c. The concentration is highest in the hydrophobic center of the outer membrane. d. It results from differences in the concentration of hydroxide ions. e. It is an electrochemical gradient.

e. It is an electrochemical gradient.

Why are single-stranded binding proteins necessary for DNA replication? a. None of the answer options is correct. b. They direct the primase where to lay down the primer. c. They provide the energy necessary to separate the two strands of DNA. d. They direct where replication will start. e. They prevent the two parental strands from coming together again.

e. They prevent the two parental strands from coming together again.

A family can share a genetic risk of developing cancer if: a. the cancer is caused by germ-line mutations. b. a somatic cell mutation in one of the genes implicated in the cancer occurred in an ancestor. c. All of these choices are correct. d. the cancer is caused by somatic cell mutations. e. a germ-line mutation in one of the genes implicated in the cancer occurred in an ancestor.

e. a germ-line mutation in one of the genes implicated in the cancer occurred in an ancestor.

The most frequent kind of mutation, a point mutation, occurs when: a. a block of nucleotides is rearranged. b. None of the other answer options is correct. c. open reading frames are altered. d. DNA repair mechanisms fail. e. a single base pair is replaced by another.

e. a single base pair is replaced by another.

The defining characteristics of active transport are that this category of transport moves substances _________ their concentration gradient and requires ___________. a. down; protein transporters b. against; protein transporters c. against; proton pumps d. down; energy e. against; energy

e. against; energy

The point at which DNA synthesis is initiated is called the: a. primase. b. primer. c. replication fork. d. start codon. e. origin of replication.

e. origin of replication.

A population of mosquitoes is exposed to the pesticide DDT for several generations. At the end of that time, most individuals in the population are resistant to DDT. The most likely reason is that: a. by chance, new mutations that led to DDT resistance arose after DDT was used. b. random mutations in each generation made mosquitoes resistant to DDT. c. somatic mutations in the original population were passed on to subsequent generations. d. DDT caused the mutations that led to resistance. e. some individuals in the original population had the mutations that led to resistance.

e. some individuals in the original population had the mutations that led to resistance.

Diffusion is best described as the random movement of molecules influenced by: a. energy transferred from molecular collisions in the cell. b. the thermal energy of the environment. c. the width of the plasma membrane of the cell. d. the thermal energy of the environment and the width of the plasma membrane. e. the thermal energy of the environment and energy transferred from molecular collisions in the cell.

e. the thermal energy of the environment and energy transferred from molecular collisions in the cell.

Ras is most similar to: a. the γ (gamma) subunit of three-subunit G proteins. b. the β (beta) subunit of three-subunit G proteins. c. receptor kinases. d. ion channels. e. the α (alpha) subunit of three-subunit G proteins.

e. the α (alpha) subunit of three-subunit G proteins.

What is the function of the enzyme DNA polymerase? a. to synthesize a strand of DNA using a polypeptide as a template b. to synthesize a polypeptide using DNA as a template c. to synthesize a strand of mRNA using DNA as a template d. to synthesize a strand of mRNA using mRNA as a template e. to synthesize a strand of DNA using DNA as a template

e. to synthesize a strand of DNA using DNA as a template

During DNA replication, the leading strand contains Okazaki fragments. false true

false

Which bonds rely on the attraction of positive and negative charges? Select all that apply. covalent bonds ionic bonds hydrogen bonds

ionic bonds hydrogen bonds

Certain meteorites have been examined and found to carry samples of which molecules? Select all that apply. nucleotides polypeptides lipids monosaccharides amino acids

lipids amino acids

What genetic material is made during the process of transcription? Select all that apply. rRNA mRNA tRNA

rRNA mRNA tRNA

Which phases of carbon fixation do not require NADPH? (Select all that apply.) a. regeneration b. reduction c. carboxylation

regeneration and carboxylation

Which enzyme is made up of both RNA and protein? RNA polymerase ribosome nucleosome

ribosome

Which cell type(s) are not the result of mitosis? Select all that apply. a. epithelial cell b. skin cell c. sperm cell d. muscle cell e. egg cell

sperm cell egg cell

Alleles are alternate molecular forms of a gene. true false

true

At equilibrium, there will be no net movement of molecules across the cell membrane. True False

true

Insertion of one nucleotide into a gene can lead to a frameshift mutation. true false

true

Which base is not found in DNA? guanine thymine adenine cytosine uracil

uracil

As part of their normal function, many proteins bind to DNA briefly and then release it again. Which types of interactions might be involved in these transient protein-DNA interactions? Select all that apply. van der Waals forces ionic bonds covalent bonds hydrogen bonds

van der Waals forces ionic bonds covalent bonds hydrogen bonds