Question 1

Achondroplasia is a form of dwarfism that is inherited in humans as an autosomal dominant disorder. A survey in a small country showed that, within a two-year period, there were 12 children with normal parents born with this disorder out of a total of 420,000 births. What is the mutation rate in mutations/locus/generation?

Accepted Answer

A)   1.4 × 10-5
B)   2.8 × 10-6
C)   2.5 × 10-5
D)   2.8 × 10-5
E)   7.4 × 10-6F) All of the above
G) B) and D)

Question 2

Which of the following base changes in DNA is an example of a transition?

Accepted Answer

A)   A to C
B)   G to C
C)   C to A
D)   A to G
E)   A to TF) A) and C)
G) C) and D)

Question 3

Suppose a research study shows that people who suffer from severe depression are homozygous for a mutation in the hypothetical DEP gene. Individuals without this form of depression have the following sequence at the beginning of the translated region of their DEP genes: 5'-ATG ACG TTT GAA ATT CAG TCT AGA-3' (Met Thr Phe Glu Ile Gln Ser Arg) . Affected individuals have the following sequence: 5'-ATG ACG TTT GAA ATT TAG TCT AGA-3'(Met Thr Phe Glu Ile STOP) . The mutation identified is most likely a:

Accepted Answer

A)   missense mutation.
B)   gain-of-function mutation.
C)   nonsense mutatio
D)   frameshift mutatio
E)   deletioF) B) and E)
G) All of the above

Question 4

In the following section of DNA, the arrows indicate transposase cleavage sites. Use diagrams to precisely describe and indicate how target site duplications are generated when transposable elements insert into DNA.

Accepted Answer

The answer of In the following section of DNA, the...

Question 5

A polypeptide has the following amino acid sequence: Met-Ala-Gln-Arg-Glu-Leu. This polypeptide was mutated to produce the following mutant sequence: Met-Ala-Gln-Thr-Gly-Thr-Ile-Thr. Which describes the MOST likely type of mutation that occurred?

Accepted Answer

A)   nonsense mutation
B)   missense mutation
C)   frameshift mutation
D)   in-frame mutation
E)   neutral mutationF) D) and E)
G) A) and D)

Question 6

The type of mutation that reverses the effects of a frameshift mutation without changing the frameshift and occurs with the same gene as the frameshift is called a(n) :

Accepted Answer

A)   intergenic suppressor mutation.
B)   nonsense mutation.
C)   missense mutation.
D)   intragenic suppressor mutation.
E)   silent mutation.F) B) and E)
G) C) and D)

Question 7

During mismatch repair, it is essential for the cell to be able to distinguish between the old template DNA strand and the newly synthesized DNA strand in order to make the appropriate correction of a mispairing created during DNA replication. How is this accomplished in E. coli?

Accepted Answer

In E. coli, the mismatch repair system i...

Question 8

What is the difference between a missense mutation and a nonsense mutation?

Accepted Answer

A missense mutation and a nonsense mutat...

Question 9

Which of the following is required for an IS element in E. coli to be able to transpose?

Accepted Answer

A)   a gene for reverse transcriptase and long terminal repeats
B)   a gene for reverse transcriptase and inverted repeats
C)   a gene for transposase and inverted repeats
D)   a gene for transposase and long terminal repeats
E)   a gene for DNA polymerase and long terminal repeatsF) D) and E)
G) A) and E)

Question 10

Insertion or removal of one or more nucleotide base pairs in DNA within a gene often results in a _____ mutation.

Accepted Answer

A)   transition
B)   frameshift
C)   reversion
D)   transversion
E)   suppressorF) A) and C)
G) All of the above

Question 11

Bacterial insertion sequences encode which of the following gene products?

Accepted Answer

A)   reverse transcriptase
B)   DNA polymerase
C)   transposase
D)   repressor
E)   insertaseF) A) and B)
G) A) and E)

Question 12

Transposable elements are found:

Accepted Answer

A)   mainly in higher plants.
B)   mainly in animals, particularly in mammals.
C)   mainly in eukaryotes.
D)   mainly in prokaryotes.
E)   in practically all organisms.F) D) and E)
G) A) and B)

Question 13

Explain how an individual with a suppressor mutation can be a double mutant but express a near normal phenotype.

Accepted Answer

An individual with a suppressor mutation...

Question 14

A polypeptide has the following amino acid sequence: Met-Ala-Gln-Arg-Glu-Leu. This polypeptide was mutated to produce the following mutant sequence: Met-Ala. Which describes the MOST likely type of mutation that occurred?

Accepted Answer

A)   nonsense mutation
B)   missense mutation
C)   frameshift mutation
D)   in-frame mutation
E)   neutral mutationF) A) and E)
G) None of the above

Question 15

How can spontaneous mutations arise?

Accepted Answer

Spontaneous mutations can arise through ...

Question 16

Assume that you have discovered a new chemical mutagen that modifies guanine so that it mispairs with adenine when adenine is in the template DNA strand during DNA replication. However, this mispairing is limited to when the modified guanine is being added to the newly replicating DNA strand. When the modified guanine is in the template DNA strand, it always pairs normally with cytosine being added to the growing newly synthesized strand. What type of mutation would you predict would be caused by the new chemical mutagen?

Accepted Answer

A)   A-to-G base substitutions
B)   A-to-C base substitutions
C)   A-to-T base substitutions
D)   A-to-G and A-to-C base substitutions
E)   G-to-T base substitutionsF) None of the above
G) C) and D)

Question 17

Assume that during DNA replication in a bacterium a mistake is made and a G is inserted into the newly synthesized DNA strand opposite a T in the template DNA strand. If this mistake is not repaired before the next round of DNA replication, what mutation will eventually result?

Accepted Answer

A)   A-to-G base substitution
B)   A-to-C base substitution
C)   A-to-T base substitution
D)   G-to-A base substitution
E)   C-to-A base substitutionF) A) and C)
G) A) and B)

Question 18

An example of a genetic disorder in humans that results from a loss-of-function mutation is:

Accepted Answer

A)   cystic fibrosis.
B)   achondroplasia.
C)   Huntington's disease.
D)   myotonic dystrophy.
E)   No correct answer is provided.F) B) and E)
G) A) and D)

Question 19

Reversions, or reverse mutations (i.e., mutations that restore the wild-type phenotype initially lost by an earlier mutation), can be either of two types: back mutations or suppressor mutations. Explain how you could distinguish between these two different types of reversions using a test cross.

Accepted Answer

To distinguish between back mutations an...

Question 20

How do insertion sequences and composite transposons differ?

Accepted Answer

Insertion sequences (IS elements) and co...

Exam 18: Gene Mutations and Dna Repair

Reversions, or reverse mutations (i.e., mutations that restore the wild-type phenotype initially lost by an earlier mutation), can be either of two types: back mutations or suppressor mutations. Explain how you could distinguish between these two different types of reversions using a test cross.

Correct Answer
Answered by ExamLex AI
To distinguish between back mutations an...
View Answer

How do insertion sequences and composite transposons differ?

Correct Answer
Answered by ExamLex AI
Insertion sequences (IS elements) and co...
View Answer

Correct Answer
verified

In the following section of DNA, the arrows indicate transposase cleavage sites. Use diagrams to precisely describe and indicate how target site duplications are generated when transposable elements insert into DNA.

Correct Answer
verified

Transposable elements are found:

Correct Answer
verified

Which of the following is required for an IS element in E. coli to be able to transpose?

Correct Answer
verified

During mismatch repair, it is essential for the cell to be able to distinguish between the old template DNA strand and the newly synthesized DNA strand in order to make the appropriate correction of a mispairing created during DNA replication. How is this accomplished in E. coli?

Correct Answer
Answered by ExamLex AI
In E. coli, the mismatch repair system i...
View Answer

Which of the following base changes in DNA is an example of a transition?

Correct Answer
verified

What is the difference between a missense mutation and a nonsense mutation?

Correct Answer
Answered by ExamLex AI
A missense mutation and a nonsense mutat...
View Answer

Correct Answer
verified

Correct Answer
verified

A polypeptide has the following amino acid sequence: Met-Ala-Gln-Arg-Glu-Leu. This polypeptide was mutated to produce the following mutant sequence: Met-Ala-Gln-Thr-Gly-Thr-Ile-Thr. Which describes the MOST likely type of mutation that occurred?

Correct Answer
verified

Explain how an individual with a suppressor mutation can be a double mutant but express a near normal phenotype.

Correct Answer
Answered by ExamLex AI
An individual with a suppressor mutation...
View Answer

Bacterial insertion sequences encode which of the following gene products?

Correct Answer
verified

Assume that during DNA replication in a bacterium a mistake is made and a G is inserted into the newly synthesized DNA strand opposite a T in the template DNA strand. If this mistake is not repaired before the next round of DNA replication, what mutation will eventually result?

Correct Answer
verified

Insertion or removal of one or more nucleotide base pairs in DNA within a gene often results in a _____ mutation.

Correct Answer
verified

How can spontaneous mutations arise?

Correct Answer
Answered by ExamLex AI
Spontaneous mutations can arise through ...
View Answer

A polypeptide has the following amino acid sequence: Met-Ala-Gln-Arg-Glu-Leu. This polypeptide was mutated to produce the following mutant sequence: Met-Ala. Which describes the MOST likely type of mutation that occurred?

Correct Answer
verified

The type of mutation that reverses the effects of a frameshift mutation without changing the frameshift and occurs with the same gene as the frameshift is called a(n) :

Correct Answer
verified

An example of a genetic disorder in humans that results from a loss-of-function mutation is:

Correct Answer
verified

Exam 18: Gene Mutations and Dna Repair

Reversions, or reverse mutations (i.e., mutations that restore the wild-type phenotype initially lost by an earlier mutation), can be either of two types: back mutations or suppressor mutations. Explain how you could distinguish between these two different types of reversions using a test cross.

Correct AnswerAnswered by ExamLex AITo distinguish between back mutations an...View AnswerShow Answer

How do insertion sequences and composite transposons differ?

Correct AnswerAnswered by ExamLex AIInsertion sequences (IS elements) and co...View AnswerShow Answer

Correct AnswerverifiedShow Answer

In the following section of DNA, the arrows indicate transposase cleavage sites. Use diagrams to precisely describe and indicate how target site duplications are generated when transposable elements insert into DNA.

Correct AnswerverifiedShow Answer

Transposable elements are found:

Correct AnswerverifiedShow Answer

Which of the following is required for an IS element in E. coli to be able to transpose?

Correct AnswerverifiedShow Answer

During mismatch repair, it is essential for the cell to be able to distinguish between the old template DNA strand and the newly synthesized DNA strand in order to make the appropriate correction of a mispairing created during DNA replication. How is this accomplished in E. coli?

Correct AnswerAnswered by ExamLex AIIn E. coli, the mismatch repair system i...View AnswerShow Answer

Which of the following base changes in DNA is an example of a transition?

Correct AnswerverifiedShow Answer

What is the difference between a missense mutation and a nonsense mutation?

Correct AnswerAnswered by ExamLex AIA missense mutation and a nonsense mutat...View AnswerShow Answer

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

A polypeptide has the following amino acid sequence: Met-Ala-Gln-Arg-Glu-Leu. This polypeptide was mutated to produce the following mutant sequence: Met-Ala-Gln-Thr-Gly-Thr-Ile-Thr. Which describes the MOST likely type of mutation that occurred?

Correct AnswerverifiedShow Answer

Explain how an individual with a suppressor mutation can be a double mutant but express a near normal phenotype.

Correct AnswerAnswered by ExamLex AIAn individual with a suppressor mutation...View AnswerShow Answer

Bacterial insertion sequences encode which of the following gene products?

Correct AnswerverifiedShow Answer

Assume that during DNA replication in a bacterium a mistake is made and a G is inserted into the newly synthesized DNA strand opposite a T in the template DNA strand. If this mistake is not repaired before the next round of DNA replication, what mutation will eventually result?

Correct AnswerverifiedShow Answer

Insertion or removal of one or more nucleotide base pairs in DNA within a gene often results in a _____ mutation.

Correct AnswerverifiedShow Answer

How can spontaneous mutations arise?

Correct AnswerAnswered by ExamLex AISpontaneous mutations can arise through ...View AnswerShow Answer

A polypeptide has the following amino acid sequence: Met-Ala-Gln-Arg-Glu-Leu. This polypeptide was mutated to produce the following mutant sequence: Met-Ala. Which describes the MOST likely type of mutation that occurred?

Correct AnswerverifiedShow Answer

The type of mutation that reverses the effects of a frameshift mutation without changing the frameshift and occurs with the same gene as the frameshift is called a(n) :

Correct AnswerverifiedShow Answer

An example of a genetic disorder in humans that results from a loss-of-function mutation is:

Correct AnswerverifiedShow Answer

Correct Answer
Answered by ExamLex AI
To distinguish between back mutations an...
View Answer

Correct Answer
Answered by ExamLex AI
Insertion sequences (IS elements) and co...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
Answered by ExamLex AI
In E. coli, the mismatch repair system i...
View Answer

Correct Answer
verified

Correct Answer
Answered by ExamLex AI
A missense mutation and a nonsense mutat...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
Answered by ExamLex AI
An individual with a suppressor mutation...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
Answered by ExamLex AI
Spontaneous mutations can arise through ...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
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