Question 1

What is the specific site on the E. coli genome where DNA replication can initiate?

Accepted Answer

A)  oriC 
B)  DnaA 
C)  primase 
D)  SeqA 
A)  oriC 
B)  DnaA 
C)  primase 
D)  SeqA A

Question 2

What DNA damage can the MGMT enzyme repair?

Accepted Answer

A)  phosphorylated adenine 
B)  methylated guanine 
C)  pyrimidine dimers 
D)  mismatched bases 
A)  phosphorylated adenine 
B)  methylated guanine 
C)  pyrimidine dimers 
D)  mismatched bases B

Question 3

Describe the Meselson-Stahl experiment and how it provided biochemical evidence that DNA replication is semiconservative.

Accepted Answer

Escherichia coli grown in ^{1 5}N-containing medium contain heavy DNA. When allowed to divide in ^{1 4}N-containing medium, a hybrid DNA is produced that contains one strand of heavy DNA and one strand of light DNA. A second round of division produces one hybrid DNA molecule and one light DNA molecule. This result could only occur through semiconservative
replication.

Question 4

What is the function of telomerase in termination of DNA synthesis?

Accepted Answer

A)  remove the telomeres 
B)  reverse transcription of the telomeres 
C)  bind to single-strand DNA to prevent refolding 
D)  shorten the DNA strand after each replication 
A)  remove the telomeres 
B)  reverse transcription of the telomeres 
C)  bind to single-strand DNA to prevent refolding 
D)  shorten the DNA strand after each replication

Question 5

Which of the following would cause a genetic mutation?

Accepted Answer

A)  DNA makes too many copies in the cell. 
B)  DNA synthesis does not occur. 
C)  DNA damage is not corrected. 
D)  Death of a cell occurs. 
A)  DNA makes too many copies in the cell. 
B)  DNA synthesis does not occur. 
C)  DNA damage is not corrected. 
D)  Death of a cell occurs.

Question 6

Explain the suicide mechanism for MGMT.

Accepted Answer

As shown in Figure 20.42 in the text, th

Question 7

Which prokaryotic polymerase is mainly responsible for DNA proofreading?

Accepted Answer

A)  Pol I 
B)  Pol II 
C)  Pol III 
D)  Pol $\alpha$ 
A)  Pol I 
B)  Pol II 
C)  Pol III 
D)  Pol $\alpha$

Question 8

An advantage of viral DNA using LTR to produce a four-nucleotide overhang on the 3'end is to

Accepted Answer

A)  start replication. 
B)  help with alignment of the viral DNA to the host DNA. 
C)  start a base mismatch repair sequence. 
D)  help with cell meiosis. 
A)  start replication. 
B)  help with alignment of the viral DNA to the host DNA. 
C)  start a base mismatch repair sequence. 
D)  help with cell meiosis.

Question 9

What is a major function of prokaryotic DNA polymerase I besides replication?

Accepted Answer

A)  very slow polymerization rate (1-2 nucleotides) to prevent mistakes 
B)  DNA translation 
C)  unlimited processivity 
D)  checking for exonuclease activity 
A)  very slow polymerization rate (1-2 nucleotides) to prevent mistakes 
B)  DNA translation 
C)  unlimited processivity 
D)  checking for exonuclease activity

Question 10

An HIV infection begins with what first step?

Accepted Answer

A)  fusion of the cell membrane and viral envelope 
B)  release of viral DNA and synthesis of cDNA 
C)  protein synthesis and processing 
D)  budding of infectious virus 
A)  fusion of the cell membrane and viral envelope 
B)  release of viral DNA and synthesis of cDNA 
C)  protein synthesis and processing 
D)  budding of infectious virus

Question 11

Using the figure below, identify conservative replication, dispersive replication, and semiconservative replication.

Accepted Answer

In this image conservative rep

Question 12

Explain the mechanism of base excision repair.

Accepted Answer

Base excision repair is mediated by shor

Question 13

What role do BRCA1 and BRCA2 play in DNA repair?

Accepted Answer

A)  find the double-strand break 
B)  assist with strand invasion 
C)  repair pyrimidine dimers 
D)  synthesize new DNA bases 
A)  find the double-strand break 
B)  assist with strand invasion 
C)  repair pyrimidine dimers 
D)  synthesize new DNA bases

Question 14

In what stage of the cell cycle does homologous recombination largely occur?

Accepted Answer

A)  G1 
B)  S 
C)  G2 
D)  meiosis 
A)  G1 
B)  S 
C)  G2 
D)  meiosis

Question 15

A Holliday junction can best be defined as a region of

Accepted Answer

A)  quadruplex DNA. 
B)  duplex DNA. 
C)  DNA damage. 
D)  DNA pyrimidine duplexes. 
A)  quadruplex DNA. 
B)  duplex DNA. 
C)  DNA damage. 
D)  DNA pyrimidine duplexes.

Question 16

If a bacteriophage activates the lytic cycle, what is the result to the host DNA?

Accepted Answer

A)  integration of virus DNA into host DNA 
B)  production of new bacteriophage particles 
C)  cell death 
D)  formation of Holliday junctions 
A)  integration of virus DNA into host DNA 
B)  production of new bacteriophage particles 
C)  cell death 
D)  formation of Holliday junctions

Question 17

What is a possible outcome when UV light reacts with riboflavin or tryptophan?

Accepted Answer

A)  methylated riboflavin 
B)  reactive oxygen species 
C)  spontaneous deglycosylation 
D)  production of an abasic site 
A)  methylated riboflavin 
B)  reactive oxygen species 
C)  spontaneous deglycosylation 
D)  production of an abasic site

Question 18

What is the function of the MutS-MutL-MutH protein complex?

Accepted Answer

A)  base excision 
B)  mismatch repair 
C)  DNA adenylation 
D)  DNA methylation 
A)  base excision 
B)  mismatch repair 
C)  DNA adenylation 
D)  DNA methylation

Question 19

Use the following figure to distinguish between the two possible outcomes from Holliday junctions.

Accepted Answer

A resolvase can bind at either sites 1 o

Question 20

How does reverse transcriptase convert RNA to DNA?

Accepted Answer

Reverse transcriptase first uses the sin

Exam 20: DNA Replication, Repair, and Recombination

What is the specific site on the E. coli genome where DNA replication can initiate?

What DNA damage can the MGMT enzyme repair?

Describe the Meselson-Stahl experiment and how it provided biochemical evidence that DNA replication is semiconservative.

What is the function of telomerase in termination of DNA synthesis?

Which of the following would cause a genetic mutation?

Explain the suicide mechanism for MGMT.

Which prokaryotic polymerase is mainly responsible for DNA proofreading?

An advantage of viral DNA using LTR to produce a four-nucleotide overhang on the 3'end is to

What is a major function of prokaryotic DNA polymerase I besides replication?

An HIV infection begins with what first step?

Using the figure below, identify conservative replication, dispersive replication, and semiconservative replication.

Explain the mechanism of base excision repair.

What role do BRCA1 and BRCA2 play in DNA repair?

In what stage of the cell cycle does homologous recombination largely occur?

A Holliday junction can best be defined as a region of

If a bacteriophage activates the lytic cycle, what is the result to the host DNA?

What is a possible outcome when UV light reacts with riboflavin or tryptophan?

What is the function of the MutS-MutL-MutH protein complex?

Use the following figure to distinguish between the two possible outcomes from Holliday junctions.

How does reverse transcriptase convert RNA to DNA?

Principles of Biochemistry

Physical Biochemistry: Energy Conversion, Water, and Membranes

Nucleic Acid Structure and Function

Protein Structure

Methods in Protein Biochemistry

Protein Function

Enzyme Mechanisms

Cell Signaling Systems

Glycolysis: a Paradigm of Metabolic Regulation

The Citrate Cycle

Oxidative Phosphorylation

Photosynthesis

Carbohydrate Structure and Function

Carbohydrate Metabolism

Lipid Structure and Function

Lipid Metabolism

Amino Acid Metabolism

Nucleotide Metabolism

Metabolic Integration

RNA Synthesis, Processing, and Gene Silencing

Protein Synthesis, Posttranslational Modification, and Transport

Gene Regulation

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