Question 1

DNA polymerase I which is inhibited by dideoxynucleoside triphosphates is used in the Sanger method for DNA sequencing.

Accepted Answer

A) True 
 B)False

Question 2

In photoreactivation, DNA damage caused by UV light is reversed by DNA photolyase which

Accepted Answer

A)   is activated by UV light to form a complex.
B)   removes nicks in the DNA backbone.
C)   forms a complex with thymine dimers which absorbs visible light and reverses the dimerization.
D)   binds to the adenine bases opposite the thymine dimer.
E)   All of the aboveF) None of the above
G) A) and C)

Question 3

The replication of DNA is because .

Accepted Answer

A)   conservative; one strand of parental DNA is retained in each daughter DNA
B)   conservative; each daughter molecule has two new strands copied from the parental DNA template
C)   semiconservative; one strand of parental DNA is retained in each daughter DNA
D)   semiconservative; each daughter molecule has two new strands copied from the parental DNA templateE) B) and D)
F) B) and C)

Question 4

DNA fingerprinting is possible for identification because each person accumulates over a hundred mutations during his or her lifetime.

Accepted Answer

A) True 
 B)False

Question 5

Since deamination is a common cause of DNA damage, and since the deamination of cytosine forms a product similar in structure to uracil, repair enzymes cannot repair this damage easily.

Accepted Answer

A) True 
 B)False

Question 6

How are the BRCA proteins and their genes implicated in breast cancer?

Accepted Answer

A)   The BRCA proteins damage DNA by generating double-stranded breaks which can lead to cancer.
B)   Cells become more susceptible to damage if the genes for these proteins are damaged.
C)   BRCA proteins inhibit excision repair mechanisms.
D)   BRCA proteins initiate recombination between non-homologous DNA sequences.E) A) and B)
F) B) and C) B

Question 7

What is the DNA sequence 5ʹ → 3ʹ)  determined in this gel? Assume the samples were applied near the top of the gel.

Accepted Answer

A)   AGGCTGGACGA
B)   AGGGGCTAGCA
C)   AGGCTGACGGA
D)   AGGCAGTCGGAE) None of the above
F) All of the above

Question 8

The polymerization of DNA is essentially irreversible due to the hydrolysis of pyrophosphate.

Accepted Answer

A) True 
 B)False

Question 9

What is the function of the primosome?

Accepted Answer

A)   Removal of RNA from the lagging strand.
B)   Synthesis of short RNA fragments.
C)   Assembly of DNA polymerase III holoenzyme.
D)   Detection of the origin of replication.E) All of the above
F) B) and D)

Question 10

In E. coli replication begins at the origin of replication and proceeds in one direction until the entire circular DNA molecule has been copied.

Accepted Answer

A) True 
 B)False

Question 11

The general excision repair pathway for DNA repair has the following order:

Accepted Answer

A)   endonuclease cuts → helicase or endonuclease removes → DNA polymerase → DNA ligase
B)   DNA ligase → DNA polymerase → helicase or endonuclease removes → endonuclease cuts
C)   endonuclease cuts → DNA polymerase repairs → helicase opens up → DNA ligase
D)   endonuclease cuts → DNA ligase removes → endonuclease removes → DNA ligaseE) A) and C)
F) None of the above

Question 12

Eukaryotic cells contain at least five DNA polymerases all of which are responsible for nuclear DNA replication.

Accepted Answer

A) True 
 B)False

Question 13

The purpose of SSB is to prevent single-stranded DNA from folding back on itself to form double-helical regions.

Accepted Answer

A) True 
 B)False

Question 14

In DNA repair, DNA glycosylases recognize deaminated bases within the DNA polymer and remove the deaminated

Accepted Answer

A)   nucleoside.
B)   nucleotide.
C)   thymine dimers.
D)   bases.E) None of the above
F) All of the above

Question 15

Meselson and Stahlʹs experiments involved growing E. coli on a medium containing 15N heavy nitrogen)  which increased the density of the bacterial DNA. Cells were then grown on a medium containing only 14N. DNA samples were obtained for analysis after one, two and three rounds of replication generations)  and centrifuged on a density gradient. The double-helical DNA forms bands in the gradient depending on its density. How many bands did Meselson and Stahl see after two generation of cells were grown on the 14N medium?

Accepted Answer

A)   One with DNA containing both 15N and 14N.
B)   Two, one with DNA containing only 15N and one with DNA containing only 14N.
C)   Two, one with DNA containing both 15N and 14N and one with DNA containing only 14N.
D)   Three, one with DNA containing only 15N, one with DNA containing both 15N and 14N and one with DNA containing only 14N.E) A) and C)
F) B) and C)

Question 16

Deaminated bases must be removed from DNA because

Accepted Answer

A)   they distort the molecule.
B)   they form thymine dimers.
C)   they pair incorrectly during replication.
D)   the mRNA formed may be irregular.E) None of the above
F) A) and B) C

Question 17

How many replisomes are required for one complete round of DNA replication in E. coli?

Accepted Answer

A)   one
B)   two
C)   four
D)   more than 4E) None of the above
F) B) and C) B

Question 18

The β subunits of E. coli DNA polymerase form a sliding clamp that surrounds the DNA strands at the replication fork.

Accepted Answer

A) True 
 B)False

Question 19

The main difference between prokaryotic and eukaryotic DNA replication mechanisms is

Accepted Answer

A)   no Okazaki fragments are made in eukaryotes.
B)   both leading and lagging strands are continuous in eukaryotes.
C)   no primer synthesis is needed in eukaryotes.
D)   the replication fork moves slower in eukaryotes.E) B) and C)
F) A) and D)

Question 20

E. coli DNA polymerase catalyzes polymerization in the directions) .

Accepted Answer

A)   5ʹ → 3ʹ
B)   3ʹ → 5ʹ
C)   2ʹ → 5ʹ
D)   both 5ʹ → 3ʹ and 3ʹ → 5ʹ
E)   All of the aboveF) C) and E)
G) C) and D)

Exam 20: Dna Replication, Repair, and Recombination

DNA polymerase I which is inhibited by dideoxynucleoside triphosphates is used in the Sanger method for DNA sequencing.

Correct Answer
verified

In photoreactivation, DNA damage caused by UV light is reversed by DNA photolyase which

Correct Answer
verified

The replication of DNA is because .

Correct Answer
verified

DNA fingerprinting is possible for identification because each person accumulates over a hundred mutations during his or her lifetime.

Correct Answer
verified

Since deamination is a common cause of DNA damage, and since the deamination of cytosine forms a product similar in structure to uracil, repair enzymes cannot repair this damage easily.

Correct Answer
verified

How are the BRCA proteins and their genes implicated in breast cancer?

Correct Answer
verified
B

What is the DNA sequence 5ʹ → 3ʹ) determined in this gel? Assume the samples were applied near the top of the gel.

Correct Answer
verified

The polymerization of DNA is essentially irreversible due to the hydrolysis of pyrophosphate.

Correct Answer
verified

What is the function of the primosome?

Correct Answer
verified

In E. coli replication begins at the origin of replication and proceeds in one direction until the entire circular DNA molecule has been copied.

Correct Answer
verified

The general excision repair pathway for DNA repair has the following order:

Correct Answer
verified

Eukaryotic cells contain at least five DNA polymerases all of which are responsible for nuclear DNA replication.

Correct Answer
verified

The purpose of SSB is to prevent single-stranded DNA from folding back on itself to form double-helical regions.

Correct Answer
verified

In DNA repair, DNA glycosylases recognize deaminated bases within the DNA polymer and remove the deaminated

Correct Answer
verified

Correct Answer
verified

Deaminated bases must be removed from DNA because

Correct Answer
verified
C

How many replisomes are required for one complete round of DNA replication in E. coli?

Correct Answer
verified
B

The β subunits of E. coli DNA polymerase form a sliding clamp that surrounds the DNA strands at the replication fork.

Correct Answer
verified

The main difference between prokaryotic and eukaryotic DNA replication mechanisms is

Correct Answer
verified

E. coli DNA polymerase catalyzes polymerization in the directions) .

Correct Answer
verified

Exam 20: Dna Replication, Repair, and Recombination

DNA polymerase I which is inhibited by dideoxynucleoside triphosphates is used in the Sanger method for DNA sequencing.

Correct AnswerverifiedShow Answer

In photoreactivation, DNA damage caused by UV light is reversed by DNA photolyase which

Correct AnswerverifiedShow Answer

The replication of DNA is because .

Correct AnswerverifiedShow Answer

DNA fingerprinting is possible for identification because each person accumulates over a hundred mutations during his or her lifetime.

Correct AnswerverifiedShow Answer

Since deamination is a common cause of DNA damage, and since the deamination of cytosine forms a product similar in structure to uracil, repair enzymes cannot repair this damage easily.

Correct AnswerverifiedShow Answer

How are the BRCA proteins and their genes implicated in breast cancer?

Correct AnswerverifiedB

What is the DNA sequence 5ʹ → 3ʹ) determined in this gel? Assume the samples were applied near the top of the gel.

Correct AnswerverifiedShow Answer

The polymerization of DNA is essentially irreversible due to the hydrolysis of pyrophosphate.

Correct AnswerverifiedShow Answer

What is the function of the primosome?

Correct AnswerverifiedShow Answer

In E. coli replication begins at the origin of replication and proceeds in one direction until the entire circular DNA molecule has been copied.

Correct AnswerverifiedShow Answer

The general excision repair pathway for DNA repair has the following order:

Correct AnswerverifiedShow Answer

Eukaryotic cells contain at least five DNA polymerases all of which are responsible for nuclear DNA replication.

Correct AnswerverifiedShow Answer

The purpose of SSB is to prevent single-stranded DNA from folding back on itself to form double-helical regions.

Correct AnswerverifiedShow Answer

In DNA repair, DNA glycosylases recognize deaminated bases within the DNA polymer and remove the deaminated

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Deaminated bases must be removed from DNA because

Correct AnswerverifiedC

How many replisomes are required for one complete round of DNA replication in E. coli?

Correct AnswerverifiedB

The β subunits of E. coli DNA polymerase form a sliding clamp that surrounds the DNA strands at the replication fork.

Correct AnswerverifiedShow Answer

The main difference between prokaryotic and eukaryotic DNA replication mechanisms is

Correct AnswerverifiedShow Answer

E. coli DNA polymerase catalyzes polymerization in the directions) .

Correct AnswerverifiedShow Answer

Correct Answer
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Correct Answer
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B

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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C

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B

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