Genetics chapter 19
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
A
A translocation that moves a gene from an area of euchromatin to heterochromatin would typically cause a/an __________ in the expression of the gene. A)reduction B)increase C)Gene expression would remain the same.
A
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 different codons D)The differences between gladiolas and snapdragons would most likely be missense mutations while those in beechdrops may be silent or missense
A
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
A
Select the correct statement regardingrate of mutation. A)Rates of spontaneous 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
A
Spontaneous mutations include __________. A)depurination, deamination, and errors in DNA replication B)UV light, radiation, deamination, and depurination C)UV light, radiation, deamination, and errors in replication D)UV light, errors in DNA replication, deamination, and depurination
A
The Holliday model is used to explain which of the following? A)Recombination between homologous chromosomes B)Recombination between sister chromatids C)The migration of transposons D)The replication of transposons E)The generation of antibody diversity
A
The complete loss of either a guanine or adenine from DNA is an example of __________. A) depurination B) tautomeric shifts C) deamination D) demethylation
A
The difference between the polymerases used in translesion synthesis repair and general DNAreplication 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 modified nucleotide binding pocket allowing for mispairing of nucleotides.
A
The formation of a D-loop is associated with which of the following models of recombination? A)Double-stranded break model B)Holliday model C)Single-stranded break model
A
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
A
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
A
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 likely alters protein function. B)Individuals with white eyes have a reversion mutation. C)It is an example of a silent mutation. D)It is an example of a neutral mutation.
A
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)? Cell line CPM in UDS assay CPM if no mutagenic event A 2,500 2,750 B 300,000 5,000 C 45,000 25,000 D 275,000 50,000 Wild-type control 750,000 75,000
A
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: 15 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
A
Which of the following best describes the function of the RecA protein in E. coli recombination? A) Promotes strand invasion and formation of the D loop B) Recognizes double-stranded breaks in the DNA C) Is involved in the initial formation of the Holliday junctions D) Resolves Holliday junctions into separate chromosomes
A
Which of the following may account for the process of gene conversion? A)DNA mismatch repair B)Retrotransposition C)Photolyase activity D)Nucleotide excision repair
A
Which types of mutations are least likely to be subjected to natural selection? A)Silent B)Missense C)Nonsense D)Insertion
A
Consider the following DNA sequence, which codes for the first portionof a long proteinbeginning at the ATG (AUG in mRNA) start codon.5' ATG CCC CGC AGTAGG GGG TGG AGA3'A mutation occurs changing this sequence to:5'ATG CCC CGC AGTAGG GAG TGG AGA3'What type of mutation is this? (Check all that apply.) A)Point mutation B)Transition C)Transversion D)Silent mutation E)Missense mutation F)Nonsense mutation G)Frameshift mutation
A B E
Consider the following DNA sequence, which codes for the first portion of a long protein beginning at the ATG (AUG in mRNA) start codon.5' ATG CCC CGC AGTAGG GGG TGG AGA3'A mutation occurs changing this sequence to:5'ATG CCC CGC AGTAGG GGG TGAAGA3'What type of mutation is this? (Check all that apply.) A)Point mutation B)Transition C)Transversion D)Silent mutation E)Missense mutation F)Nonsense mutation G)Frameshift mutation
A B F
Consider the following DNA sequence, which codes for the first portionof a long protein beginning at the ATG (AUG in mRNA) start codon.5' ATG CCC CGC AGTAGG GGG TGG AGA3'A mutation occurs changing this sequence to:5'ATG CCGCGC AGTAGG GGG TGGAGA3'What type of mutation is this? (Check all that apply.) A)Point mutation B)Transition C)Transversion D)Silent mutation E)Missense mutation F)Nonsense mutation G)Frameshift mutation
A C D
A culture of E. coli bacteria is used to establish several subcultures. Each subculture is then plated and individual 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? A)Physiological adaptation theory B)Random mutation theory C)Both theories D)Neither theory
B
A temporary change in the conformation of a nitrogenous base is called __________. A)depurination B)a tautomeric shift C)deamination D)None of these choices are correct.
B
Consider the following DNA sequence, which codes the first portionof a long proteinbeginning at the ATG (AUG in mRNA) start codon.5' ATG CCC CGC AGTAGG GGG TGG AGA 3'Which of the mutatedsequences listed is most likely to be a deleterious mutation? A)5'ATG CCC CGC AGTAGG GAG TGG AGA3' B)5'ATG CCC CGC AGTAGG GGG TGAAGA3' C)5'ATG CCGCGC AGTAGG GGG TGGAGA3'
B
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.
B
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
B
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
B
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)
B
Which of the following most likely accounts for the majority of the recombination events during both DNA repair and meiosis? A)A nick in only one strand of the DNA B)Double-stranded breaks in DNA C)DNA gap repair synthesis D)Heteroduplex formation
B
An example of a base analog would be __________. A) EMS B) nitrous acid C) 5BU D) nitrogen mustards E) acridine dyes
C
In E. coli, a mutation in the genes encoding which of the following proteins would disable the ability of the cell to recognize double-stranded breaks and conduct recombination during meiosis? A)RecG B)RecA C)RecBCD D)RuvABC
C
The conversion of cytosine to uracil in DNA is an example of __________. A)depurination B)tautomeric shifts C)deamination D)demethylation
C
Translocations and inversions may result in __________. A)TNRE B)anticipation C)position effect D)genome mutations
C
Which DNA repair mechanism uses DNAN-glycosylases? A)Recombinational repair B)Direct repair C)Base excision repair D)Mismatch repair E)Nucleotide excision repair F)Nonhomologous end joining (NHEJ)
C
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 10 5 B) 1.0 x 10 -5 C) 3.0 x 10 5 D) 3.3 x 10 -5
D
Anticipation is associated with which type of mutation? A) Nonsense mutations B) Up-promoter mutations C) Intergenic suppressors D) TNRE mutations E) None of these choices are correct.
D
Mutations that change the configuration of a protein at a specific temperature are called __________ mutations. A) neutral B) beneficial C) deleterious D) conditional
D
Select the example of an induced mutational mechanism. A)DNA replication errors B)Tautomeric shifts of nucleic acid bases C)Aberrant recombination D)UV light E)Transposable elements
D
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)
D
Which repair mechanism is responsible for repairing damage from UV light? A)Recombinational repair B)Base excision repair C)Mismatch repair D)Nucleotide excision repair E)Nonhomologous end joining (NHEJ)
D
Which repair mechanism utilizes MutL, MutH, and MutS proteins in E. coli? A)Recombinational repair B)Direct repair C)Base excision repair D)Mismatch repair E)Nucleotide excision repair F)Nonhomologous end joining (NHEJ)
D
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
E
You are a doctor tasked with diagnosing a patient that comes to you with mental impairment. Upon performing genetic tests, you find he has approximately 300 repeats of GCC in one of his genes. His father and grandfather had similar mental impairment but were never diagnosed with a condition prior to their death. His grandmother, mother, and sisters are unaffected. What disease do you predict that this patient has? A)SBMA B)HD C)SCA1 D)FRAXA E)FRAXE
E
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)
F
A change in the chromosome number is called a point mutation.
false
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.
false
An individual that is a genetic mosaic would be the result of a germ cell mutation.
false
Ethyl methanesulfonate (EMS) is an example of a deaminating agent.
false
Somatic cells are those that give rise to sperm and egg cells.
false
TNRE repeats frequently result in the addition of extra histidine amino acids to the protein.
false
The most common genotype in a population is called the mutant genotype.
false
The mutation frequency would be the same for all genes in a given culture.
false
A heritable change in the genetic material is called a mutation.
true
A heteroduplex is a DNA double helix that contains mismatches.
true
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.
true
Breakpoints in chromosomes can lead to mutant phenotypes when they occur in the middle of a gene.
true
HRR usually uses a sister chromatid.
true
Silent mutations are possible due to the degenerate nature of the genetic code.
true
The Ames test may be used to determine if an agent is a mutagen.
true
The mutation frequency for a genes the ratio of the number of mutant genes to the total number of copies of that gene in a given population.
true
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.
true
