16. The term mutation refers to:
A) only changes in the DNA that result in new phenotypes.
B) only changes in the DNA that result in novel proteins.
C) any change in the DNA of a cell.
D) a heritable change in the DNA of a cell.
E) any change in the cell
D
17. A heritable change in DNA base sequence is called a:
A) forward mutation.
B) reversion.
C) substitution.
D) deletion.
E) mutation.
E
18. Replacing a thymine nucleotide with a guanine is an example of a:
A) translocation.
B) transition.
C) transversion.
D) forward mutation.
E) reversion or reverse mutation.
C
19. Replacing an adenine nucleotide with a guanine is an example of a:
A) translocation.
B) transition.
C) transversion.
D) forward mutation.
E) reversion or reverse mutation.
B
20. Assume that a wild-type sequence is 5'AGCCTAC3'. Indicate the sequence that might be produced by a transversion.
A) 5'AGTCTAC3'
B) 5'AGCCGCCGCCGCCTAC3'
C) 5'AGCCCAC3'
D) 5'ATCCTAC3'
E) 5'AGCCTGC3'
D
21. A mutation in which parts of two nonhomologous chromosomes change places is called a:
A) translocation.
B) transition.
C) transversion.
D) insertion.
E) deletion.
A
22. Indicate the statement that is most accurate regarding mutations.
A) Most mutations alter protein structure and phenotype.
B) Only those mutations that alter protein structure will alter phenotype.
C) Mutations altering a region that does not code for
C
23. Assume that the mutation rate for a given gene is 510-6 mutations per gene per generation. For that gene how many mutations would be expected if 10 million sperm are examined?
A) none
B) 510-6
C) 5
D) 50
E) 500
D
24. Which type of mutation is least likely to revert?
A) deletion
B) transition
C) transversion
D) insertion
E) all are equally likely
A
25. Consider the following results. When 50 million sperm were examined for a specific mutation, 100 mutations were found. Indicate the mutation rate for that gene.
A) 510-6
B) 5010-6
C) 210-6
D) 210-5
E) 510-5
C
26. Assume that a researcher set out to duplicate the Luria-Delbruck fluctuation experiment. This researcher planted twenty small flasks with bacteria from the same colony and let them grow overnight. The next morning the researcher noticed that all but o
D
27. The results of the Luria-Delbruck fluctuation experiment indicated that:
A) bacteria are naturally resistant to phage.
B) a low level of any bacteria population are naturally resistant to phage.
C) bacteria become resistant to phage by mutation when e
D
28. In the Luria-Delbruck fluctuation experiment, the bacteria + phage plates showed:
A) all plates had some resistant colonies, some had very many.
B) some plates had no resistant colonies, a few plates had very many resistant colonies.
C) all plates had
B
29. The hydrolysis of a purine base from the deoxyribose-phosphate backbone is called:
A) depurination.
B) deamination.
C) replica plating.
D) excision repair.
E) deletion.
A
30. Assume that in the organism under study the DNA polymerase has an error rate of 1 mistake in every 106 bases copied. However, the overall mutation rate is much lower. This is most likely because:
A) the polymerase is more careful in replicating region
B
31. Excision repair corrects DNA by:
A) removing a double-stranded fragment of damaged DNA.
B) detecting, removing, and replacing a single stranded fragment of damaged DNA.
C) excising the incorrect base from a nucleotide.
D) removing extraneous groups su
B
32. Thymine dimers are caused by:
A) X-rays.
B) free radicals such as oxygen.
C) EMS or NSG.
D) depurination.
E) UV light.
E
33. UV light is a mutagen that can cause:
A) depurination.
B) deamination.
C) alkylation.
D) thymine dimers.
E) oxidation.
D
34. The genetic condition xeroderma pigmentosum, which can lead to skin cancer, results from:
A) inability to correct UV induced dimers.
B) inability to process phenylamine.
C) inability to produce functional hemoglobin.
D) inability to correct transition
A
35. The bacterial repair system that corrects mismatched bases after polymerization is able to discriminate between the old and newly made DNA strands because:
A) the new strand will contain the incorrect base if a mismatch occurs.
B) older DNA is more li
C
36. The consequence to a bacterial cell of a mutation that inactivated the enzyme that methylates the A of the sequence GATC in newly made DNA would be:
A) failure to carry out replication.
B) failure to correct thymine dimers.
C) failure to distinguish o
C
37. Unequal crossing over results in:
A) an exchange between nonhomologous chromosomes.
B) a loss of genetic material.
C) a repair of UV-induced damage.
D) a production of eggs containing Y chromosomes.
E) a creation of deletions and duplications.
E
38. The heritable disorder fragile X syndrome, a major cause of mental retardation, is caused by:
A) production of enzymes that break the phosphate backbone.
B) UV light.
C) X-rays.
D) presence of an extra X chromosome in the sperm or egg.
E) duplication
E
39. If a man shows the premutation allele for fragile X syndrome, what is the probability that he will pass it on to his son?
A) 100%
B) 75%
C) 50%
D) 25%
E) 0%
E
40. The duplication of the triplet sequence CGG resulting in elongation or breakage of the X chromosome is termed:
A) Barr-eyed.
B) Huntington's disease.
C) unequal crossing over.
D) fragile X syndrome.
E) Rhys syndrome.
D
41. Genes on the X chromosome of mammals and Drosophila are particularly suitable for genetic study because:
A) males have only one X and most genes behave as haploids.
B) females have only one X and most genes behave as haploids.
C) the X chromosome is l
A
42. If a base analog such as 5-Bromouracil is used as a mutagen, how many generations will be required to mutate the codon for proline (CCC) into the codon for alanine (GCC)?
A) one generation
B) two generations
C) three generations
D) at lease two, but p
E
43. Base analogs differ from other classes of mutagen in that they:
A) only alter bases.
B) can only cause transversions.
C) only work during DNA replication or repair.
D) can only cause forward mutations, nor reversions.
E) will not function in bacterial
C
44. Intercalating agents such as acridine orange function as mutagens to:
A) promote transitions.
B) remove amine groups.
C) attach to purines causing distortions.
D) add ethyl or methyl groups.
E) fit between stacked bases and disrupt replication.
E
45. Alkylating agents such as ethylmethane sulfate (EMS) function as mutagens to:
A) promote deletions and insertions.
B) remove amine groups.
C) add oxygen free radicals to bases.
D) add ethyl or methyl groups.
E) fit between stacked bases and disrupt re
D
46. In the Ames test for mutagenicity:
A) auxotrophic bacteria are converted to prototrophs which survive.
B) prototrophic bacteria are converted to auxotrophs which survive.
C) cells are treated with mutagen and only those with no mutations survive.
D) c
A
47. In the Ames test for mutagenicity, rat liver enzymes are included with the compound under test because:
A) bacterial cell walls must be treated to permit uptake of the compounds.
B) rat liver enzymes increase the sensitivity of the bacteria to mutagen
D
48. Assume that a new low-calorie sweetener is developed. The structure is novel and is tested with the Ames test for mutagenicity. The following results are obtained:
Sample Number of his+ revertent colonies
distilled water 2
distilled water + rat liver
C
49. The Ames test for mutagenicity is useful to identify potential carcinogens because:
A) since bacteria do not get cancer they can survive lethal carcinogens.
B) mutagens that affect bacterial DNA are likely to cause human mutation.
C) bacteria thrive o
B
50. The size of the human genome in base-pairs is about:
A) 210 million
B) 100,000
C) 2.75 106
D) 2.75 109
E) 2.75 1010
D
51. A complementation group is:
A) a group of mutations that produce the same phenotype.
B) a group of mutations that are in the same gene and complement each other.
C) a group of mutations that are in the same gene and do not complement each other.
D) a
C
52. Choose the statement that is most correct regarding the rII- strain of T4 that Benzer studied.
A) Produces smaller plaques than wild type.
B) Produces smaller plaques, grows in E. coli K(), not in E. coli B.
C) Produces larger plaques, grows in E. col
D
53. A plaque is:
A) a colony of bacteria growing on a plate.
B) a colony of bacteria that contain phage within them.
C) a region on a plate where living bacteria survive phage infection.
D) an area on a plate containing live phage-resistant bacteria.
E) a
E
54. Shown below are the results of a series of coinfections using T4 rII- strains similar to those employed by Benzer. Each strain contains a different deletion mutation. Ability to produce wild-type progeny phage is indicated by (+), (o) indicates no wil
A
55. Shown below are the results of a series of coinfections using T4 rII- strains similar to those employed by Benzer. Each strain contains a different deletion mutation. Ability to produce wild-type progeny phage is indicated by (+), (o) indicates no wil
C
56. Choose the statement that best distinguishes a complementation test and a recombination analysis when examining mutations in phage.
A) Both tests require two different mutations.
B) Recombination can only occur between two genes.
C) Complementation re
C
57. Shown below are the deletion maps of a series of rII- mutations. The deleted region is indicated as (......) and the intact region as ______.
1 _____(..........)____________________
2 _________________(..........)________
3 (.........)________________
D
58. Shown below are the deletion maps of a series of rII- mutations. The deleted region is indicated as (......) and the intact region as ______.
1 ___________(...........)_______________
2 _________________(...........)_________
3 (.....................)
B
59. Shown below are the deletion maps of a series of rII- mutations. The deleted region is indicated as (......) and the intact region as ______. Note that strain 5 carries two different deletions.
1 ___________(...........)_______________
2 _____________
A
60. Indicate the correct order for one round of infection by bacteriophage T4.
1. Lysis of host cell.
2. Phage proteins and DNA synthesized, host DNA degraded.
3. Assembly of phage within host cell.
4. Phage body enters host cell.
5. Phage injects DNA int
D
61. How many progeny phage are released when a single E. coli cell is lysed by phage T4?
A) between 1 and 10
B) between 10 and 100
C) between 100 and 1,000
D) about 10,000
E) about 100,000
C
62. Indicate which of the following is least important in doing a complementation test with coinfection of phage T4.
A) Ensuring that sufficient phage of both strains are present.
B) Recovering phage from the plaques after growth and lysis.
C) Counting th
C
63. Assume that a researcher is studying coat color in voles. Three strains of white vole have been isolated: milky, blanc, and weiss. White is a recessive trait in each strain. Homozygous white voles are obtained for each strain. Consider the following c
C
64. Assume a researcher is studying the rII locus of phage T4. Three rII- strains are obtained: A, B, and C. When coinfections are performed in E. coli strain K() the following results are obtained:
A B = plaques form
A C = plaques form
B C = no plaque
D
65. Assume a researcher is studying the rII locus of phage T4. Four rII- strains are obtained: A, B, C and D. When coinfections are performed in E. coli strain K() the following results are obtained:
A B = lysis
A C = lysis
B C = no lysis
B D = no lys
D
66. Choose the statement that is most accurate concerning biochemical pathways.
A) All enzymes in the pathway catalyze the same reaction.
B) If an enzyme in a pathway is inactive, adding excessive amounts of its substrate will restore the normal phenotype
C
67. Assume 7 different strains of fly have been isolated, each shows a recessive white eye trait. Crosses are performed as follows; (w) indicates white-eyed progeny, (R) indicates wild-type red eyes.
Based on these crosses, how many different genes are pr
C
68. Assume 8 different strains of fly have been isolated, each shows a recessive white eye trait. Crosses are performed as follows; (w) indicates white-eyed progeny, (R) indicates wild-type red eyes.
Based on these crosses, how many different genes are pr
D
69. In the human genetic disorder alkaptonuria, urine turns black because of the presence of homogentisic acid in individuals with the trait. This is due to:
A) the presence of large amounts of homogentisic acid in the diet.
B) failure of individuals with
E
70. Consider the pathway for the synthesis of the amino acid arginine in Neurospora:
ARG-E ARG-F ARG-H
ornithine citrulline argininosuccinate arginine
Mutant strains of Neurospora are grown in minimal media supplements as follows. Each mutant strain ca
A
71. Consider the pathway for the synthesis of the amino acid arginine in Neurospora:
ARG-E ARG-F ARG-H
ornithine citrulline argininosuccinate arginine
Mutant strains of Neurospora are grown in minimal media supplements as follows. Strains may carry mor
A
72. Consider the pathway for the synthesis of the amino acid arginine in Neurospora:
ARG-E ARG-F ARG-H
ornithine citrulline argininosuccinate arginine
Mutant strains of Neurospora are grown in minimal media supplements as follows. The strains may carry
E
73. Indicate the false statement regarding amino acids.
A) Every amino acid contains a carboxyl group.
B) The side chain or R group differs for each amino acid.
C) Amino acids are joined together by peptide bonds.
D) The end of the polypeptide termed the
E
74. Indicate the false statement regarding amino acids.
A) Several amino acids linked together are termed an oligopeptide.
B) Amino acids are linked by peptide bonds that join two amino groups together.
C) The C terminus of a polypeptide chain contains a
B
75. Choose the condition below that does not involve a defect in an enzyme pathway.
A) alkaptonuria
B) albinism
C) sickle-cell anemia
D) phenylketonuria (PKU)
E) all of the above involve a defect in an enzyme pathway
C
76. Choose the interaction listed below that is not involved in maintaining tertiary structure in protein molecules.
A) covalent bond
B) hydrogen bond
C) hydrophobic/hydrophilic interactions
D) ionic interactions
E) all of the above may be involved in mai
E
77. The condition sickle-cell anemia is due to:
A) the insertion of an amino acid.
B) the deletion of an amino acid.
C) substitution of an amino acid.
D) failure to synthesize a hemoglobin molecule.
E) unequal recombination resulting in the deletion of th
C
78. Choose the statement below that is not true regarding sickle-cell anemia.
A) Individuals who are heterozygous for the sickle cell allele can not make hemoglobin.
B) The sickle-cell hemoglobin molecule contains an amino acid substitution.
C) The hemogl
A
79. Though sickle-cell anemia is frequently lethal for individuals who are homozygous for the sickle cell allele, natural selection seems to have maintained that allele in certain geographic locations. A likely explanation for this observation is:
A) the
D
80. The structure of a polypeptide that is characterized by a three dimensional shape with a characteristic geometry at local regions maintained by hydrogen bonds is:
A) primary structure.
B) secondary structure.
C) tertiary structure.
D) quaternary struc
B
81. The structure of a protein that involves the interaction between two distinct polypeptide chains is:
A) primary structure.
B) secondary structure.
C) tertiary structure.
D) quaternary structure.
E) both primary and secondary structure.
B
82. Assume that a certain strain of bacteria carries a mutation that causes it to die at high temperature (37C), but grows normally at cooler temperatures. This mutation is termed:
A) recessive.
B) deletion.
C) biochemical pathway mutant.
D) conditional l
E
83. Mutations that abolish the function encoded by the wild-type allele are known as:
A) null mutations.
B) hypomorphic mutations.
C) hypermorphic mutations.
D) conditional mutations.
E) neomorphic mutations.
A
84. A neomorphic mutation results in an allele that:
A) produces no gene product.
B) produces a nonfunctional gene product.
C) produces novel proteins or cause inappropriate expression resulting in a new phenotype.
D) produces proteins that aggregate with
C
85. Assume that a transition mutation results in an amino acid substitution in the resulting polypeptide. What level of protein structure might be affected as a result?
A) primary structure
B) secondary structure
C) tertiary structure
D) quaternary struct
E
86. The photoreceptor protein rhodopsin:
A) is found in cone cells and is sensitive to weak light at many wavelengths.
B) is found in rod cells and is sensitive to weak light at many wavelengths.
C) is found in cone cells and is responsible for blue and g
B
87. Examination of the rhodopsin gene family provides evidence for gene evolution by:
A) duplication and divergence.
B) accumulation of random mutations.
C) convergent evolution.
D) spontaneous generation.
E) drift.
A
88. Red-green color blindness is more common in males than females because:
A) the red pigment gene is on the X chromosome, the green is on an autosome.
B) the green pigment gene is on the X chromosome, the red is on an autosome.
C) rhodopsin gene is on t
D
89. Consider the gene for color in a particular flower. Three alleles exist: dark blue, white, and sky. Flowers homozygous for each allele produce the characteristic color. In heterozygotes, incomplete dominance occurs and intermediate colors are seen in
D
90. The appearance of a novel phenotype resulting from the substitution of a single base pair might be due to:
A) change in the amino acid sequence only.
B) change in the amount of protein expressed.
C) alteration in a gene that codes for a nontranslated
E
91. Assume that a series of compounds has been discovered in Neurospora. Compounds A-F appear to be members of an enzyme pathway. Several mutations have been identified and strains 1-4 each contain a single mutation. Shown below are 5 possible pathways. C
E
92. Assume that a series of compounds has been discovered in Neurospora. Compounds A-F appear to be members of an enzyme pathway. Several mutations have been identified and strains 1-4 each contains a single mutation. Shown below are 5 possible pathways.
D
93. The term fecundity refers to:
A) ability to live a long life.
B) ability to survive in several different conditions.
C) ability to transcribe DNA.
D) ability to produce offspring.
E) ability to metabolize several different sugar molecules.
D
94. Assume that for a given gene a mutation creates an allele that functions as a dominant negative. The gene codes for a protein that forms a trimer within the cell. If at least one of the subunits has the mutant structure the entire protein is inactivat
E
95. A neomorphic dominant mutation in the Antennapedia (Antp) gene of Drosophila causes:
A) kinks to form in their tails.
B) shortened tails.
C) total loss of color vision.
D) failure to assemble microtubules during mitosis.
E) growth of leg from the head
E
Which type of mutation is most likely to revert?
A) deletion
B) translocation
C) inversion
D) transposition
E) transition
D
The hydrolysis of an -NH2 group from a base is called ________, while intercalating agents such as acridine orange function as mutagens by causing ________:
A) deamination; transversions
B) deamination; deletions or insertions
C) excision repair; deletion
B
Mutations that reduce the function encoded by the wild-type allele are known as ________, while mutations that eliminate all function are known as ________:
A) null mutations; neomorphic mutations
B) hypomorphic mutations; null mutations
C) hypermorphic m
B
A conditional bacterial mutant is unable to methylate DNA at higher temperatures. What happens when you shift bacteria to these higher temperatures?
A) the new DNA strand is more likely to contain errors
B) the older DNA strand is more likely to contain e
D
Duplication of multiple three-nucleotide repeats is responsible for:
A) sickle-cell anemia
B) xeroderma pigmentosum
C) alkaptonuria
D) trisomy 21
E) fragile X syndrome
E
In an Ames test for mutagenicity, rat liver enzymes are accidentally excluded from the compound under test. What can you say about the results?
A) the mutation rate will probably rise
B) the mutation rate will probably decline
C) the results are less rele
A
Assume that a new antidepressant is developed. The structure is novel and is tested using the Ames test for mutagenicity. The following results are obtained:
--------------------------------------------------------------------------------
Sample Number of
D
A stock of T4 phage is diluted by a factor of 10-7 and 0.1 ml of it is mixed with 0.1 ml of 108 E. coli/ml and 2.5 ml melted agar, and poured on the surface of an agar petri dish. The next day, 100 plaques are visible. What is the concentration (in plaque
D
Mutations that are in the same gene and do not complement each other are:
A) a complementation group
B) alleles
C) deletions
D) a and b
E) none of the above
D
Assume four strains (A-D) of pure-breeding stippled lettuce have been isolated. Given the results of the following crosses:
A X C = stippled
A X B = wild type
A X D = wild type
B X C = wild type
B X D = stippled
C X D = wild type
What are the complementat
B
Assume 8 different strains of mouse have been isolated, each showing a recessive tail phenotype. Crosses are performed as follows; (+) indicates wild type, (0) indicates the behavioral trait.
A B C D E F G H
A 0 0 + + + + + +
B 0 + + + + + +
C 0 + 0 + 0 +
D
Consider the pathway for the synthesis of the amino acid arginine in Neurospora:
ARG-F ARG-G ARG-H
ornithine ? citrulline ? succinate ? arginine e e
Mutant strains of Neurospora are grown in minimal media with supplements as follows. Each mutant strain ca
C
What is the principal determinant of overall protein structure?
A) the carboxyl group.
B) the amino group
C) peptide bonds
D) amino acid sequence
E) none of the above
D
An amino acid substitution in a protein can have:
A) a large effect on protein structure
B) a small effect on protein structure
C) little to no effect on protein structure
D) all of the above
E) none of the above
D
An observable phenotype may arise from a change in:
A) the amino acid sequence
B) the control of protein expression
C) the amino acid sequence of an interacting subunit
D) all of the above
E) a and c
D
A null allele can be dominant to the fully functional wild-type allele due to:
A) haploinsufficiency
B) codominance
C) incomplete dominance
D) neomorphism
E) not true, a null allele is always recessive to a fully functional wild-type allele
A
Gene evolution is best illustrated by:
A) the rhodopsin gene family
B) inborn errors of metabolism
C) X-linked traits
D) sickle cell anemia
E) xeroderma pigmentosum
A
Assume that for a given gene a mutation creates an allele that functions as a partially dominant negative as follows. The gene codes for a protein that forms a dimer within the cell. If one of the subunits has the mutant structure, the entire protein is 2
C