Question 1

In the Ames test, the clear region of no growth near the center of the plate (where the compound of interest is placed)  typically indicates that the compound is:

Accepted Answer

A)   not mutagenic.
B)   an antibiotic.
C)   an amino acid.
D)   lethal at high enough concentrations.
E)   not taken up by bacteria.F) C) and D)
G) A) and D)

Question 2

Which statement is TRUE regarding the process catalyzed by the bacteriophage  λ\lambdaλ  integrase?

Accepted Answer

A)   Serines in the protein active site become covalently attached to the nucleic acids during the mechanism.
B)   The reaction is an ATP-dependent process.
C)   The reaction steps are successive tranesterifications.
D)   The integrase can be classified as a hydrolase.
E)   The target DNA sequence for this protein is nonspecific. F) A) and B)
G) B) and E)

Question 3

When a DNA molecule is described as replicating bidirectionally, that means that it has two:

Accepted Answer

A)   chains.
B)   independently replicating segment.
C)   origins.
D)   replication forks.
E)   termination points.F) All of the above
G) A) and E)

Question 4

How many rounds of replication would result in a 1:1 distribution of hybrid to new DNA helices in the Meselson and Stahl experiment?

Accepted Answer

A)   one
B)   two
C)   three
D)   four
E)   fiveF) All of the above
G) D) and E)

Question 5

Match the damage type or repair step at the left with a related enzyme at right. Only one answer will be the most direct for each.

Accepted Answer

To match the damage type or repair step ...

Question 6

All known DNA polymerases catalyze synthesis only in the 5' $\rightarrow$  3' direction. Nevertheless, during semiconservative DNA replication in the cell, they are able to catalyze the synthesis of both daughter chains, which would appear to require synthesis in the 3' $\rightarrow$  5' direction. Explain the process that occurs in the cell that allows for synthesis of both daughter chains by DNA polymerase.

Accepted Answer

DNA replication is a semiconservative pr...

Question 7

Explain the role of DNA glycosylases in DNA repair.

Accepted Answer

DNA glycosylases are enzymes that play a...

Question 8

Which feature is NOT applicable to homologous recombination during meiosis?

Accepted Answer

A)   a double strand break
B)   cleavage of two crossover events
C)   alignment of homologous chromosomes
D)   formation of a single Holliday intermediate
E)   exposed 3ʹ ends invade the intact duplex DNA of the homologF) B) and D)
G) B) and E)

Question 9

In the bacterial cell, what are catenated chromosomes, when do they arise, and how does the cell resolve the problem posed by their structure?

Accepted Answer

Catenated chromosomes in a bacterial cel...

Question 10

In contrast to bacteria, eukaryotic chromosomes need multiple DNA replication origins because:

Accepted Answer

A)   eukaryotic chromosomes cannot usually replicate bidirectionally.
B)   eukaryotic genomes are not usually circular, like the bacterial chromosome is.
C)   the processivity of the eukaryotic DNA polymerase is much less than the bacterial enzyme.
D)   their replication rate is much slower, and it would take too long with only a single origin per chromosome.
E)   they have a variety of DNA polymerases for different purposes, and need a corresponding variety of replication origins.F) A) and E)
G) B) and E)

Question 11

The RNA primase in the E. coli Pol III replisome is one of the most highly error-prone polymerases known. Explain why this does not affect the accuracy of DNA replication in E. coli.

Accepted Answer

RNA primase is an enzyme that synthesize...

Question 12

E. coli DNA polymerase III:

Accepted Answer

A)   can initiate replication without a primer.
B)   is efficient at nick translation.
C)   is the principal DNA polymerase in chromosomal DNA replication.
D)   represents over 90% of the DNA polymerase activity in E. coli cells.
E)   requires a free 5'-hydroxyl group as a primer.F) B) and E)
G) A) and C)

Question 13

Which statement does NOT describe a feature of site-specific recombination?

Accepted Answer

A)   A specific recombinase enzyme is required.
B)   The energy of the phosphodiester bond is preserved in covalent enzyme-DNA linkage.
C)   Recombination sites have non-palindromic sequences.
D)   Formation of Holliday intermediates is required.
E)   Insertions or deletions can result from site-specific recombination.F) D) and E)
G) B) and E)

Question 14

DNA replication in E. coli:

Accepted Answer

A)   of the leading strand requires multiple primers.
B)   is mostly 3'to 5'.
C)   always finishes at a conserved terminator sequence.
D)   requires DNA-dependent RNA synthesis.
E)   does not require the action of topoisomerases.F) All of the above
G) A) and C)

Question 15

Which statement about enzymes that interact with DNA is TRUE?

Accepted Answer

A)   E. coli DNA polymerase I is unusual in that it possesses only a 5'  →\rightarrow→ 3' exonucleolytic activity.
B)   Endonucleases degrade circular but not linear DNA molecules.
C)   Exonucleases degrade DNA at a free end.
D)   Many DNA polymerases have a proofreading 5'  →\rightarrow→  3' exonuclease.
E)   Primases synthesize a short stretch of DNA to prime further synthesis. F) D) and E)
G) A) and E)

Question 16

Which compound is NOT required for initiation of DNA replication in E. coli?

Accepted Answer

A)   DnaB (helicase) 
B)   DnaG (primase) 
C)   Dam methylase
D)   DNA ligase
E)   DnaA (a AAA+ ATPase) F) All of the above
G) B) and E)

Question 17

DnaA binds to what sites in the E. coli origin?

Accepted Answer

A)   R sites only
B)   I sites only
C)   DUE sites only
D)   both R and I sites
E)   both R and DUE sitesF) D) and E)
G) A) and D)

Question 18

It is possible to mutate E. coli DNA Pol I so that it no longer has any exonuclease activity. What would be a potential result of this change?

Accepted Answer

A)   The enzyme would become more processive.
B)   The enzyme would be more error prone.
C)   The enzyme would become more efficient in base excision repair.
D)   The enzyme would become more processive and more error-prone.
E)   None of these is a potential outcome.F) B) and E)
G) C) and D)

Question 19

What distinguishes the two mechanistic pathways for transposition in bacteria, and what is a cointegrate?

Accepted Answer

The two mechanistic pathways for transpo...

Question 20

In a mammalian cell, DNA repair systems:

Accepted Answer

A)   are extraordinarily efficient energetically.
B)   are generally absent, except in egg and sperm cells.
C)   can repair deletions, but not mismatches.
D)   can repair most types of lesions except those caused by UV light.
E)   normally repair more than 99% of the DNA lesions that occur.F) A) and E)
G) B) and E)

Exam 25: DNA Metabolism

Which statement about enzymes that interact with DNA is TRUE?

Correct Answer
verified

In a mammalian cell, DNA repair systems:

Correct Answer
verified

When a DNA molecule is described as replicating bidirectionally, that means that it has two:

Correct Answer
verified

Which compound is NOT required for initiation of DNA replication in E. coli?

Correct Answer
verified

Which statement is TRUE regarding the process catalyzed by the bacteriophage $\lambda$ integrase?

Correct Answer
verified

Which statement does NOT describe a feature of site-specific recombination?

Correct Answer
verified

Explain the role of DNA glycosylases in DNA repair.

Correct Answer
Answered by ExamLex AI
DNA glycosylases are enzymes that play a...
View Answer

How many rounds of replication would result in a 1:1 distribution of hybrid to new DNA helices in the Meselson and Stahl experiment?

Correct Answer
verified

Correct Answer
Answered by ExamLex AI
DNA replication is a semiconservative pr...
View Answer

In contrast to bacteria, eukaryotic chromosomes need multiple DNA replication origins because:

Correct Answer
verified

It is possible to mutate E. coli DNA Pol I so that it no longer has any exonuclease activity. What would be a potential result of this change?

Correct Answer
verified

DnaA binds to what sites in the E. coli origin?

Correct Answer
verified

Match the damage type or repair step at the left with a related enzyme at right. Only one answer will be the most direct for each.

Correct Answer
Answered by ExamLex AI
To match the damage type or repair step ...
View Answer

The RNA primase in the E. coli Pol III replisome is one of the most highly error-prone polymerases known. Explain why this does not affect the accuracy of DNA replication in E. coli.

Correct Answer
Answered by ExamLex AI
RNA primase is an enzyme that synthesize...
View Answer

DNA replication in E. coli:

Correct Answer
verified

Which feature is NOT applicable to homologous recombination during meiosis?

Correct Answer
verified

What distinguishes the two mechanistic pathways for transposition in bacteria, and what is a cointegrate?

Correct Answer
Answered by ExamLex AI
The two mechanistic pathways for transpo...
View Answer

In the Ames test, the clear region of no growth near the center of the plate (where the compound of interest is placed) typically indicates that the compound is:

Correct Answer
verified

In the bacterial cell, what are catenated chromosomes, when do they arise, and how does the cell resolve the problem posed by their structure?

Correct Answer
Answered by ExamLex AI
Catenated chromosomes in a bacterial cel...
View Answer

E. coli DNA polymerase III:

Correct Answer
verified

Exam 25: DNA Metabolism

Which statement about enzymes that interact with DNA is TRUE?

Correct AnswerverifiedShow Answer

In a mammalian cell, DNA repair systems:

Correct AnswerverifiedShow Answer

When a DNA molecule is described as replicating bidirectionally, that means that it has two:

Correct AnswerverifiedShow Answer

Which compound is NOT required for initiation of DNA replication in E. coli?

Correct AnswerverifiedShow Answer

Which statement is TRUE regarding the process catalyzed by the bacteriophage λ\lambdaλ integrase?

Correct AnswerverifiedShow Answer

Which statement does NOT describe a feature of site-specific recombination?

Correct AnswerverifiedShow Answer

Explain the role of DNA glycosylases in DNA repair.

Correct AnswerAnswered by ExamLex AIDNA glycosylases are enzymes that play a...View AnswerShow Answer

How many rounds of replication would result in a 1:1 distribution of hybrid to new DNA helices in the Meselson and Stahl experiment?

Correct AnswerverifiedShow Answer

Correct AnswerAnswered by ExamLex AIDNA replication is a semiconservative pr...View AnswerShow Answer

In contrast to bacteria, eukaryotic chromosomes need multiple DNA replication origins because:

Correct AnswerverifiedShow Answer

It is possible to mutate E. coli DNA Pol I so that it no longer has any exonuclease activity. What would be a potential result of this change?

Correct AnswerverifiedShow Answer

DnaA binds to what sites in the E. coli origin?

Correct AnswerverifiedShow Answer

Match the damage type or repair step at the left with a related enzyme at right. Only one answer will be the most direct for each.

Correct AnswerAnswered by ExamLex AITo match the damage type or repair step ...View AnswerShow Answer

The RNA primase in the E. coli Pol III replisome is one of the most highly error-prone polymerases known. Explain why this does not affect the accuracy of DNA replication in E. coli.

Correct AnswerAnswered by ExamLex AIRNA primase is an enzyme that synthesize...View AnswerShow Answer

DNA replication in E. coli:

Correct AnswerverifiedShow Answer

Which feature is NOT applicable to homologous recombination during meiosis?

Correct AnswerverifiedShow Answer

What distinguishes the two mechanistic pathways for transposition in bacteria, and what is a cointegrate?

Correct AnswerAnswered by ExamLex AIThe two mechanistic pathways for transpo...View AnswerShow Answer

In the Ames test, the clear region of no growth near the center of the plate (where the compound of interest is placed) typically indicates that the compound is:

Correct AnswerverifiedShow Answer

In the bacterial cell, what are catenated chromosomes, when do they arise, and how does the cell resolve the problem posed by their structure?

Correct AnswerAnswered by ExamLex AICatenated chromosomes in a bacterial cel...View AnswerShow Answer

E. coli DNA polymerase III:

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Which statement is TRUE regarding the process catalyzed by the bacteriophage $\lambda$ integrase?

Correct Answer
verified

Correct Answer
verified

Correct Answer
Answered by ExamLex AI
DNA glycosylases are enzymes that play a...
View Answer

Correct Answer
verified

Correct Answer
Answered by ExamLex AI
DNA replication is a semiconservative pr...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
Answered by ExamLex AI
To match the damage type or repair step ...
View Answer

Correct Answer
Answered by ExamLex AI
RNA primase is an enzyme that synthesize...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
Answered by ExamLex AI
The two mechanistic pathways for transpo...
View Answer

Correct Answer
verified

Correct Answer
Answered by ExamLex AI
Catenated chromosomes in a bacterial cel...
View Answer

Correct Answer
verified