Deck 18: Gene Mutation and Dna Repair

Question 1

The results of the replica plating experiments by the Lederbergs supported which theory?

A)Random mutation theory
B)Physical adaptation theory
C)Both theories
D)Neither theory

Answer 1

A

Question 2

In the following sequence of DNA, the italicized base has been mutated. What type of mutation is this? 5' - G A T C T C C G A A T T - 3' original strand
5' - G A T C T C C C A A T T - 3' mutated strand

A)Transition
B)Transversion
C)Neither

Answer 2

B

Question 3

Most TNRE repeats involve expansion of which codon?

A)GAA
B)CAG
C)ATG
D)CCC
E)Any codon containing three of the same bases

Answer 3

B

Question 4

A temporary change in the conformation of a nitrogenous base is called ______.

A)Depurination
B)A tautomeric shift
C)Deamination
D)None of the answers are correct

Question 5

Which DNA repair mechanism uses DNA-N-glycolases?

A) Recombinational repair
B) Direct repair
C) Base excision repair
D) Mismatch repair
E) Nucleotide excision repair
F) Nonhomologous end joining (NHEJ)

Question 6

Translocations and inversions may result in

A)TNRE
B)Anticipation
C)Position effect
D)Genome mutations

Question 7

Which repair mechanism identifies daughter strands by methylation?

A)Recombinational repair
B)Direct repair
C)Base excision repair
D)Mismatch repair
E)Nucleotide excision repair
F) Nonhomologous end joining (NHEJ)

Question 8

Which repair mechanism is responsible for repairing damage from UV radiation?

A) Recombinational repair
B) Base excision repair
C) Mismatch repair
D) Nucleotide excision repair
E) Nonhomologous end joining (NHEJ)

Question 9

Anticipation is associated with which type of mutation?

A)Nonsense mutations
B)Up-promoter mutations
C)Intergenic suppressors
D)TNRE mutations
E)None of the answers are correct

Question 10

An example of a base analog would be

A)EMS
B)Nitrous acid
C)5BU
D)Nitrogen mustards
E)Acridine dyes

Question 11

Darwin's theory of natural selection supported the physical adaptation theory.

Question 12

A translocation that moves a gene from an area of euchromatin to heterochromatin would typically cause a(n) _______ in the expression of the gene.

A)Reduction
B)Increase
C)Gene expression would remain the same

Question 13

Which repair mechanism utilizes MutL, MutH, and MutS proteins in

A)Recombinational repair
B)Direct repair
C)Base excision repair
D)Mismatch repair
E)Nucleotide excision repair
F) Nonhomologous end joining (NHEJ)

Question 14

Which repair mechanism often leads to deletions in chromosomes?
A.Recombinational repair
B.Direct repair
C.Base excision repair
D.Mismatch repair
E.Nucleotide excision repair
F. Nonhomologous end joining (NHEJ)

Question 15

Photolyase in yeast is an example of what kind of DNA repair mechanism?

A) Recombinational repair
B) Direct repair
C) Base excision repair
D) Mismatch repair
E) Nucleotide excision repair
F) Nonhomologous end joining (NHEJ)

Question 16

The complete loss of either a guanine or adenine from DNA is an example of _____.

A)Depurination
B)Tautomeric shifts
C)Deamination
D)Demethylation

Question 17

The conversion of cytosine to uracil in DNA is an example of _____.

A)Depurination
B)Tautomeric shifts
C)Deamination
D)Demethylation

Question 18

What is the difference between a forward and reverse mutation?

A) A forward mutation is beneficial to the organism, while a reverse mutation is harmful to the organism.
B) A forward mutation changes the genotype to the wild-type genotype, while a reverse mutation changes the genotype to a mutant genotype.
C) A forward mutation changes the wild-type genotype to some new genetic combination, while a reverse mutation changes a genotype to the wild-type genotype.
D) None of the answers are correct

Question 19

Which is not an example of a induced mutational mechanism?

A)DNA replication errors
B)Tautomeric shifts of nucleic acid bases
C)Aberrant recombination
D)UV light
E)Transposable elements

Question 20

How does position effect influence gene expression?

A) Point mutations in promoters frequently occur by this mechanism
B) Translocations may result in a promoter that is normally used for one gene now controlling an entirely different gene.
C) Since this mechanism relies on recombination it relies on the positioning of one allele so that it is under the control of the other allele.
D) Translocations always result in a gene being recombined into an area of heterochromatin.

Question 21

A mutagen is

A)an agent that can alter the structure of DNA and cause mutations.
B)a depurinated base.
C)a DNA polymerase without a 5' to 3' exonuclease.
D)a deaminated base.

Question 22

Ethyl methanesulfonate (EMS) is an example of a deaminating agent.

Question 23

The Ames test may be used to determine if an agent is a mutagen.

Question 24

In the nucleotide excision repair system, which of the following proteins is responsible for recognizing a thymine dimer to be repaired?

A)UvrA/UvrB
B)UvrC
C)UvrD
D)UvrE

Question 25

HRR usually uses a sister chromatid.

Question 26

Silent mutations are possible due to the degenerate nature of the genetic code.

Question 27

Evolution is the result of selecting only those mutations that result in an increased reproductive success.

Question 28

TNRE repeats frequently result in the addition of extra histidine amino acids to the protein.

Question 29

Spontaneous mutations include

A)Depurination, deamination, errors in DNA replication
B)UV light, radiation, deamination, depurination
C)UV light, radiation, deamination, errors in replication
D)UV light, errors in DNA replication, deamination, depurination

Question 30

An individual that is a genetic mosaic would be the result of a germ cell mutation.

Question 31

The difference between the polymerases used in translesion syntheis repair and general DAN replication is

A) The polymerase used in translesion synthesis has a pocket that can accommodate the lesions while DNA pol III's pocket cannot
B) There is no real difference between the polymerases except that the translesional polymerase is not part of the replication complex
C) The polymerase used in translesion synthesis has a pocket that cannot accommodate the lesions, that is part of the mechanism by which the lesions are removed.
D) The polymerase used to remove the lesion has a mdofied nucleotide binding pocket allowing for mispairing of nucleotides.

Question 32

Somatic cells are those that give rise to sperm and egg cells.

Question 33

The mutation frequency is the ratio of the number of mutant alleles to the total number of alleles in a given population.

Question 34

A change in the chromosome number is called a point mutation.

Question 35

The most common genotype in a population is called the mutant genotype.

Question 36

A mutation in a promoter region that causes the promoter sequence to more closely resemble the consensus sequence is called an up promoter mutation and results in a decrease in transcription.

Question 37

The term polarity is associated with mutations in eukaryotic cells.

Question 38

The mechanism for reactive oxygen species to cause mutation is

A)bases are oxidized to a variety of different products which might pair with a different base than the original base would have.
B)thymine bases are dimerized which causes a break in the DNA which is not repaired correctly.
C)the reactive oxygen species stabilize different tautomeric forms of the bases causing inappropriate pairing.
D)guanine is depurinated by the reactive oxygen species and if it is not repaired can result in any base being inserted.

Question 39

Breakpoints in chromosome can lead to mutant phenotypes when they occur in the middle of a gene.

Question 40

A mutation in one gene that compensates for a mutation in another gene to result in the wild-type phenotype is called an intergenic suppressor mutation.

Question 41

Which types of mutations are least likely to be subjected to natural selection?

A)Silent
B)Missense
C)Nonsense
D)Insertion

Question 42

There is a spectrum of syndromes in humans known as Xeroderma pigmentosum. The individuals that have XD most commonly have mutations in their nucleotide excision DNA repair mechanisms that make them particularly susceptible to environmental mutagens such as UV light. Individuals have to be careful with how much sunlight they are exposed to since they have an extremely elevated chance for developing skin cancer.. There have been several cell lines that have been established from XD patients that can be studied in tissue culture. In an experiment several different cell lines of unknown origin were tested for their ability to undergo unscheduled DNA synthesis (UDS), an assay for DNA repair. In this assay the amount of radioactive nucleotides that are incorporated into DNA after the cell sustains a mutagenic event are measured. The amount of radioactivity incorporated is measured by the number of counts per minute (CPM). Below is a table from such an experiment. Which cell line is most likely from XD patient(s)?

A)A
B)B
C)C
D)D

Question 43

Beechdrops is a parasitic plant that cannot perform photosynthesis but relies on its host the Beech tree. However, Beechdrops still retains many if not all of the genes for photosynthesis. Snapdragons and gladiolas are common garden flowers that rely on their ability to perform photosynthesis. If you were to compare the gene sequences for these three plants for ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) a protein necessary for photosynthesis what would you predict?

A) The differences between gladiolas and snapdragons would most likely be silent mutations while those in beechdrops may be silent or missense
B) Since these three plants are not highly related the sequences for RuBisCO would be very different between them
C) The differences between gladiolas and snapdragons would most likely be in the second nucleotide of codons while beechdrops would have a higher number of mutations in the third nucleotide of the diffferent codons
D) The differences between gladiolas and snapdragons would most likely be missense mutations while those in beechdrops may be silent or missense

Question 44

After screening a colony of bacteria for mutations in a given gene, you discover 100 mutant colonies out of 3 million total colonies. What is the mutation frequency for this gene in the population?

A)1.0 x 10⁵
B)1.0 x 10^-5
C)3.0 x 10⁵
D)3.3 x 10^-5

Question 45

Mutations that change the configuration of a protein at a specific temperature are called ____ mutations.

A)Neutral
B)Beneficial
C)Deleterious
D)Conditional

Question 46

An example of a mutagen that integrates into the double-helix of DNA resulting in the inhibition of DNA replication would be

A)EMS
B)Nitrous acid
C)5BU
D)2-amino purine
E)Acridine dyes

Question 47

The mutation frequency would be the same for all genes in a given culture.

Question 48

What would be a set of anticipated results from a "Lederberg" experiment?

A) Total number of colonies on a plate: 1500 Total number of resistant colonies on replica plate with T1: 150
B) Total number of colonies on a plate: 1500 Total number of resistant colonies on replica plate with T1: 1500
C) Total number of colonies on a plate: 500 Total number of resistant colonies on replica plate with T1: 1500
D) Total number of colonies on a plate: 1500 Total number of resistant colonies on replica plate with T1: 0

Question 49

A heritable change in the genetic material is called a mutation.

Question 50

A culture of

A) Physiological adaptation theory
B) Random mutation theory
C) Both theories
D) Neither theory
E)coli bacteria is used to establish several subcultures.Each subculture is then plated and individulal colonies that grow on the agar plates are then tested for their sensitivity to the bacteriophage T1. There is a spectrum of sensitivities where some plates have a high number of resistant colonies and some plates had very few. This data supports which theory?

Question 51

The process of replica plating was designed to test if mutations occurred in response to a selective agent or if mutations were naturally present in the population before selection.

Question 52

A sample of water is tested for mutagens. The water is subjected to a process known as high pressure liquid chromatography which can separate compounds based on their different biochemical properties. As material leaves the HPLC column its absorbance is measured at UV light which is used to detect a variety of different compounds. These readings were recorded as a trace on a graph (top chart in the figure). Fractions from the column are collected and then tested in an Ames assay (bottom chart in the figure). In this assay there were 900 colonies with the solvent alone control. Which fractions contain mutagens?

A) 7 and 16
B) 3 and 10
C) 3, 7, 10, and 16
D) None of these fractions appear to contain a mutagen

Question 53

The wild-type eye color of Drosophila is red. A single-base mutation can occur that produces a white eye color. What statement is correct regarding this mutation?

A)It is an example of a mutation that alters protein function
B)Individuals with white eyes have a reversion mutation
C)It would be an example of a silent mutation
D)The white eyed phenotyope is called an example of a neutral mutation.

Question 54

An example of a suppressor mutation would be

A)An intragenic mutation that restores the inactive protein's structure
B)An intergenic mutation that increases the activity of a protein performing a different function as the mutated protein
C)An intergenic mutation that activates a transcription factor that increases the espression of a normal protein
D)A mutation that suppresses cell growth

Question 55

Select the correct satement regarding the rate of mutation?

A)Rates of mutation per cell generation typically range from 10^-5 to 10^-9
B)Mutation rates are consistent across species
C)Mutation rates are not influenced by environmental conditions
D)Mutation rates are constant