Genetics Exam test quizzes and
answers graded A+
1. A class of mutations that results in multiple contiguous amino acid changes in proteins is likely to
be the following: - ANS✅✅d. Frameshift
2. Mutations that reduce the function encoded by the wildtype allele are known as _______, while
mutations that eliminate all function are known as ______. - ANS✅✅b. Hypomorphic mutations;
null mutations
3. Deamination of cytosine: - ANS✅✅c. Can be repaired by base-excision repair
4. Neutral mutations: - ANS✅✅Do not alter the product of a gene
Occur frequently in the noncoding regions of the genome
Can be used to estimate mutation rates
Are expected to accumulate over time
*all of these are correct
5. Genes within an operon: - ANS✅✅Tend to be regulated by a common regulatory mechanism.
Are generally involved in the same biochemical pathway.
Are expressed as a polycistronic RNA.
*all are correct
6. The lac repressor... - ANS✅✅Binds to the operator in the Lac operon
Binds lactose
7. Which of the following would you expect to find in an inducible system? - ANS✅✅a. A repressor
protein, which is bound to DNA in absence of any other factor.
8. DNA sites bound by regulatory transcription factors: - ANS✅✅b. Are cis acting elements.
, 9. The zinc-finger motif functions to - ANS✅✅b. Anchor transcriptional activator proteins to
enhancer sequences
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. - ANS✅✅B) CAA to TAA
Which of these describes a similarity between the lac and ara operons?
A) Expression of structural genes does not occur at high glucose concentrations.
B) lacI and araI both encode transacting factors.
C) Binding of a regulatory protein is prevented in the presence of an inducer.
D) All of these are similarities.
E) Noneofthesearesimilarities. - ANS✅✅A) Expression of structural genes does not occur at high
glucose concentrations
Assume that in the organism under study the DNA polymerase has an error rate of 1 mistake in
every 10^6 bases copied. However, the overall mutation rate is much lower. This is most likely
because:
A)the polymerase is more careful in replicating regions where genes exist.
B)repair mechanisms correct errors made by the polymerase.
C)not all mutations can be detected easily.
D)the DNA polymerase has no proofreading function. mutations do not occur if mutagens are not
present. - ANS✅✅repair mechanisms correct errors made by the polymerase.
The quaternary structure of proteins is represented by the __________.
answers graded A+
1. A class of mutations that results in multiple contiguous amino acid changes in proteins is likely to
be the following: - ANS✅✅d. Frameshift
2. Mutations that reduce the function encoded by the wildtype allele are known as _______, while
mutations that eliminate all function are known as ______. - ANS✅✅b. Hypomorphic mutations;
null mutations
3. Deamination of cytosine: - ANS✅✅c. Can be repaired by base-excision repair
4. Neutral mutations: - ANS✅✅Do not alter the product of a gene
Occur frequently in the noncoding regions of the genome
Can be used to estimate mutation rates
Are expected to accumulate over time
*all of these are correct
5. Genes within an operon: - ANS✅✅Tend to be regulated by a common regulatory mechanism.
Are generally involved in the same biochemical pathway.
Are expressed as a polycistronic RNA.
*all are correct
6. The lac repressor... - ANS✅✅Binds to the operator in the Lac operon
Binds lactose
7. Which of the following would you expect to find in an inducible system? - ANS✅✅a. A repressor
protein, which is bound to DNA in absence of any other factor.
8. DNA sites bound by regulatory transcription factors: - ANS✅✅b. Are cis acting elements.
, 9. The zinc-finger motif functions to - ANS✅✅b. Anchor transcriptional activator proteins to
enhancer sequences
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. - ANS✅✅B) CAA to TAA
Which of these describes a similarity between the lac and ara operons?
A) Expression of structural genes does not occur at high glucose concentrations.
B) lacI and araI both encode transacting factors.
C) Binding of a regulatory protein is prevented in the presence of an inducer.
D) All of these are similarities.
E) Noneofthesearesimilarities. - ANS✅✅A) Expression of structural genes does not occur at high
glucose concentrations
Assume that in the organism under study the DNA polymerase has an error rate of 1 mistake in
every 10^6 bases copied. However, the overall mutation rate is much lower. This is most likely
because:
A)the polymerase is more careful in replicating regions where genes exist.
B)repair mechanisms correct errors made by the polymerase.
C)not all mutations can be detected easily.
D)the DNA polymerase has no proofreading function. mutations do not occur if mutagens are not
present. - ANS✅✅repair mechanisms correct errors made by the polymerase.
The quaternary structure of proteins is represented by the __________.
