Test Bank: Concepts of Genetics, 3rd Edition by
Brooker , Chapters 1-24, 9781259879906 | Rationals
Included
Mutations:
A) Are permanent changes in the DNA sequence or structure.
B) Produce allelic variation.
C) Are more likely to be harmful than beneficial.
D) All of the above.
E) None of the above. - ANSWER:D
A frameshift mutation could be caused by:
A) A transition.
B) A transversion.
C) A deletion of 3 bp.
D) All of these.
E) None of these. - ANSWER:E
Because they only affect a single amino acid, missense mutations do not have a significant effect on
protein function.
A) True
B) False - ANSWER:B
Which of the following point mutations would be most likely to affect protein function?
A) TAA to TGA
B) CAA to TAA
C) AGG to AGA
D) CTT to CTC
E) All of these are likely to affect protein function. - ANSWER:B
A wild type allele:
A) Is the allele that is the most common in the population.
B) Is the allele with the highest level of functional protein.
C) Is the most favorable allele in the population.
D) All of the above.
E) None of the above. - ANSWER:A
The mutation which causes sickle cell anemia in humans:
A) Is a base substitution.
B) Is a deleterious mutation.
C) Is a missense mutation.
D) All of the above.
E) None of the above. - ANSWER:D
The gene that is mutated in cases of cystic fibrosis encodes an ion transporter protein normally
expressed in the respiratory and digestive tracts along with other locations. Individuals homozygous
for the most common mutation in this gene (ΔF508) died at very early ages prior to the advent of
advanced medical intervention. Despite this, the mutation exists at relatively high frequency in
populations of European descent. One potential explanation is that heterozygotes for such mutations
may be relatively immune to the lethal effects of diseases such as typhoid fever. Which statement
below is most accurate?
A) The ΔF508 cystic fibrosis mutation is a beneficial mutation.
B) The ΔF508 cystic fibrosis mutation is a lethal mutation.
, C) The ΔF508 cystic fibrosis mutation is a conditional mutation.
D) The ΔF508 cystic fibrosis mutation is a neutral mutation.
E) The ΔF508 cystic fibrosis mutation is a suppressor mutatio - ANSWER:B
In Himalayan rabbits, the ears, feet, and muzzle are pigmented while the rest of the body is white.
This is because they express an enzyme variant that is ineffective at body temperature but functions
at the lower temperatures experienced by cells of the extremities. This is an example of:
A) A wild type allele.
B) A lethal mutation.
C) A suppressor mutation.
D) A conditional mutation. - ANSWER:D
A splice site mutation leading to loss of an exon can affect production of regions of the protein
encoded in downstream exons even if they are spliced correctly.
A) True
B) False - ANSWER:A
Provided the number of base pairs is a multiple of three, insertion of additional DNA in the coding
region of a protein is unlikely to have a dramatic effect on protein function.
A) True
B) False - ANSWER:B
A woman with mild symptoms of myotonic muscular dystrophy has a daughter with a very severe
form of the disease. Which of the following statements is most correct?
A) The daughter probably has a mutation with the same number of repeats as her mother.
B) The mother probably has a mutation with a larger number of repeats than the daughter.
C) This must be an X-linked dominant condition.
D) This is an example of anticipation. - ANSWER:D
Chromosomal rearrangements are unlikely to produce an obvious phenotype, since they do not
remove any DNA.
A) True
B) False - ANSWER:B
Which of these is NOT a mechanism by which a chromosome rearrangement could affect gene
function?
A) The breakpoint is in the middle of the coding region.
B) The breakpoint is between the coding region and the regulatory elements.
C) The new arrangement puts a gene near new regulatory elements.
D) A gene is moved near a locus control region.
E) None (all of these may be caused by rearrangements and affect gene function). - ANSWER:E
Which of the following would be an example of a germline mutation?
A) Exposure to excessive UV radiation causes changes in the DNA of a skin cell, leading to basal cell
carcinoma (skin cancer).
B) In a very early human embryo, a mistake in mitosis causes loss of a Y chromosome in one daughter
cell. The resulting child is a fertile male who is chromosomally partially male (XY) and partially female
with Turner's syndrome (XO).
C) A man with normal chromosomes has a hip X-ray without a protective shield. Ten months later, his
wife gives birth to a child with a chromosomal deletion.
D) An embryo missing one copy of the third chromosome is miscarried very early in pregnancy. -
ANSWER:C
Mitochondrial DNA polymerase does not have an error checking mechanism such as that of nuclear
DNA polymerase. This would be expected to lead to a higher rate of which type of mutation in
mitochondrial DNA?
A) Spontaneous mutations.
Brooker , Chapters 1-24, 9781259879906 | Rationals
Included
Mutations:
A) Are permanent changes in the DNA sequence or structure.
B) Produce allelic variation.
C) Are more likely to be harmful than beneficial.
D) All of the above.
E) None of the above. - ANSWER:D
A frameshift mutation could be caused by:
A) A transition.
B) A transversion.
C) A deletion of 3 bp.
D) All of these.
E) None of these. - ANSWER:E
Because they only affect a single amino acid, missense mutations do not have a significant effect on
protein function.
A) True
B) False - ANSWER:B
Which of the following point mutations would be most likely to affect protein function?
A) TAA to TGA
B) CAA to TAA
C) AGG to AGA
D) CTT to CTC
E) All of these are likely to affect protein function. - ANSWER:B
A wild type allele:
A) Is the allele that is the most common in the population.
B) Is the allele with the highest level of functional protein.
C) Is the most favorable allele in the population.
D) All of the above.
E) None of the above. - ANSWER:A
The mutation which causes sickle cell anemia in humans:
A) Is a base substitution.
B) Is a deleterious mutation.
C) Is a missense mutation.
D) All of the above.
E) None of the above. - ANSWER:D
The gene that is mutated in cases of cystic fibrosis encodes an ion transporter protein normally
expressed in the respiratory and digestive tracts along with other locations. Individuals homozygous
for the most common mutation in this gene (ΔF508) died at very early ages prior to the advent of
advanced medical intervention. Despite this, the mutation exists at relatively high frequency in
populations of European descent. One potential explanation is that heterozygotes for such mutations
may be relatively immune to the lethal effects of diseases such as typhoid fever. Which statement
below is most accurate?
A) The ΔF508 cystic fibrosis mutation is a beneficial mutation.
B) The ΔF508 cystic fibrosis mutation is a lethal mutation.
, C) The ΔF508 cystic fibrosis mutation is a conditional mutation.
D) The ΔF508 cystic fibrosis mutation is a neutral mutation.
E) The ΔF508 cystic fibrosis mutation is a suppressor mutatio - ANSWER:B
In Himalayan rabbits, the ears, feet, and muzzle are pigmented while the rest of the body is white.
This is because they express an enzyme variant that is ineffective at body temperature but functions
at the lower temperatures experienced by cells of the extremities. This is an example of:
A) A wild type allele.
B) A lethal mutation.
C) A suppressor mutation.
D) A conditional mutation. - ANSWER:D
A splice site mutation leading to loss of an exon can affect production of regions of the protein
encoded in downstream exons even if they are spliced correctly.
A) True
B) False - ANSWER:A
Provided the number of base pairs is a multiple of three, insertion of additional DNA in the coding
region of a protein is unlikely to have a dramatic effect on protein function.
A) True
B) False - ANSWER:B
A woman with mild symptoms of myotonic muscular dystrophy has a daughter with a very severe
form of the disease. Which of the following statements is most correct?
A) The daughter probably has a mutation with the same number of repeats as her mother.
B) The mother probably has a mutation with a larger number of repeats than the daughter.
C) This must be an X-linked dominant condition.
D) This is an example of anticipation. - ANSWER:D
Chromosomal rearrangements are unlikely to produce an obvious phenotype, since they do not
remove any DNA.
A) True
B) False - ANSWER:B
Which of these is NOT a mechanism by which a chromosome rearrangement could affect gene
function?
A) The breakpoint is in the middle of the coding region.
B) The breakpoint is between the coding region and the regulatory elements.
C) The new arrangement puts a gene near new regulatory elements.
D) A gene is moved near a locus control region.
E) None (all of these may be caused by rearrangements and affect gene function). - ANSWER:E
Which of the following would be an example of a germline mutation?
A) Exposure to excessive UV radiation causes changes in the DNA of a skin cell, leading to basal cell
carcinoma (skin cancer).
B) In a very early human embryo, a mistake in mitosis causes loss of a Y chromosome in one daughter
cell. The resulting child is a fertile male who is chromosomally partially male (XY) and partially female
with Turner's syndrome (XO).
C) A man with normal chromosomes has a hip X-ray without a protective shield. Ten months later, his
wife gives birth to a child with a chromosomal deletion.
D) An embryo missing one copy of the third chromosome is miscarried very early in pregnancy. -
ANSWER:C
Mitochondrial DNA polymerase does not have an error checking mechanism such as that of nuclear
DNA polymerase. This would be expected to lead to a higher rate of which type of mutation in
mitochondrial DNA?
A) Spontaneous mutations.
