Question 1

What is DNA gyrase?

Accepted Answer

A)  a bacterial type II topoisomerase 
B)  a bacterial type I topoisomerase 
C)  a bacterial helicase 
D)  a eukaryotic helicase 
E)  None of the answers is correct. 
A)  a bacterial type II topoisomerase 
B)  a bacterial type I topoisomerase 
C)  a bacterial helicase 
D)  a eukaryotic helicase 
E)  None of the answers is correct.

Question 2

DNA polymerase III is able to correct mistakes in replication due to its _________________ function.

Accepted Answer

The answer of DNA polymerase III is able to correct...

Question 3

Why is shape complementarity so important in DNA replication?

Accepted Answer

Residues of the polymerase enzyme form h

Question 4

Why is the site of DNA synthesis called the replication fork?

Accepted Answer

The complex formed by the newl

Question 5

What role does the protein RecA play in recombination?

Accepted Answer

RecA promotes the formation of

Question 6

What does the phrase "recombination of genetic material" refer to?

Accepted Answer

Two daughter molecules are for

Question 7

Huntington's disease is caused by

Accepted Answer

A)  pyrimidine dimers. 
B)  trinucleotide expansion. 
C)  improper DNA methylation. 
D)  suppressor mutants. 
E)  None of the answers is correct. 
A)  pyrimidine dimers. 
B)  trinucleotide expansion. 
C)  improper DNA methylation. 
D)  suppressor mutants. 
E)  None of the answers is correct.

Question 8

Which of the following is (are)true?

Accepted Answer

A)  Naturally occurring DNA usually has negative supercoiling. 
B)  Forms with the same linking number can be interconverted without cleavage. 
C)  The twist value rarely changes in naturally occurring DNA. 
D)  All the answers are correct. 
E)  Naturally occurring DNA usually has negative supercoiling, and forms with the same linking number can be interconverted without cleavage. 
A)  Naturally occurring DNA usually has negative supercoiling. 
B)  Forms with the same linking number can be interconverted without cleavage. 
C)  The twist value rarely changes in naturally occurring DNA. 
D)  All the answers are correct. 
E)  Naturally occurring DNA usually has negative supercoiling, and forms with the same linking number can be interconverted without cleavage.

Question 9

What is true about DNA polymerases?

Accepted Answer

A)  There are at least five structural classes. 
B)  All have finger and thumb domains that wrap around the DNA. 
C)  All catalyze the same reaction, which requires metal cofactors. 
D)  All the answers are correct. 
E)  There are five structural classes, and all catalyze the same reaction, which requires metal cofactors. 
A)  There are at least five structural classes. 
B)  All have finger and thumb domains that wrap around the DNA. 
C)  All catalyze the same reaction, which requires metal cofactors. 
D)  All the answers are correct. 
E)  There are five structural classes, and all catalyze the same reaction, which requires metal cofactors.

Question 10

Which of the following is a short section of RNA that is extended by DNA polymerase?

Accepted Answer

A)  telomere 
B)  primer 
C)  Okazaki fragment 
D)  Holliday fragment 
E)  None of the answers is correct. 
A)  telomere 
B)  primer 
C)  Okazaki fragment 
D)  Holliday fragment 
E)  None of the answers is correct.

Question 11

What describes the number of times a DNA strand winds around the helix axis when the axis lies in a plane?

Accepted Answer

A)  linking number 
B)  writhe number 
C)  twist number 
D)  supercoil number 
E)  None of the answers is correct. 
A)  linking number 
B)  writhe number 
C)  twist number 
D)  supercoil number 
E)  None of the answers is correct.

Question 12

How is replication specificity dictated?

Accepted Answer

A)  Proper base-pairing is dictated more by shape than by hydrogen bonding capacity. 
B)  Enzyme interactions with the DNA act as a "ruler" to determine if the properly spaced base pair has been formed. 
C)  The bond is broken and reformed to ensure its accurate placement at each base pair. 
D)  All the answers are correct. 
E)  A and B are both correct. 
A)  Proper base-pairing is dictated more by shape than by hydrogen bonding capacity. 
B)  Enzyme interactions with the DNA act as a "ruler" to determine if the properly spaced base pair has been formed. 
C)  The bond is broken and reformed to ensure its accurate placement at each base pair. 
D)  All the answers are correct. 
E)  A and B are both correct.

Question 13

Aflatoxin B1 is a compound that is converted to a reactive epoxide by a cytochrome P450 enzyme and causes

Accepted Answer

A)  a G-C to T-A transversion. 
B)  an intrastrand cross-link. 
C)  deamination of adenine. 
D)  deamination of cytosine. 
E)  None of the answers is correct. 
A)  a G-C to T-A transversion. 
B)  an intrastrand cross-link. 
C)  deamination of adenine. 
D)  deamination of cytosine. 
E)  None of the answers is correct.

Question 14

How can the leading and lagging strands be synthesized in a coordinated fashion?

Accepted Answer

A)  Specific enzymes control the size of the DNA opening. 
B)  Lagging-strand binding proteins inhibit leading-strand replication if the strands become disproportionate in size. 
C)  DNA polymerase III is a dimeric holoenzyme, and the looped lagging strand allows the enzyme to proceed in the same direction with each strand. 
D)  Leading and lagging strand syntheses are catalyzed by two distinct and noninteracting replisomes, but the rate is controlled by helicase. 
E)  None of the answers is correct. 
A)  Specific enzymes control the size of the DNA opening. 
B)  Lagging-strand binding proteins inhibit leading-strand replication if the strands become disproportionate in size. 
C)  DNA polymerase III is a dimeric holoenzyme, and the looped lagging strand allows the enzyme to proceed in the same direction with each strand. 
D)  Leading and lagging strand syntheses are catalyzed by two distinct and noninteracting replisomes, but the rate is controlled by helicase. 
E)  None of the answers is correct.

Question 15

The tertiary structures in DNA are created by the process known as ______________.

Accepted Answer

The answer of The tertiary structures in DNA are created...

Question 16

What name is given to the short sections of DNA found on the lagging strand during DNA synthesis?

Accepted Answer

A)  primer fragments 
B)  template fragments 
C)  supercoiled fragments 
D)  Holliday fragments 
E)  Okazaki fragments 
A)  primer fragments 
B)  template fragments 
C)  supercoiled fragments 
D)  Holliday fragments 
E)  Okazaki fragments

Question 17

The observed error rate in DNA replication is approximately

Accepted Answer

A)  1 per 106 nucleotides. 
B)  1 per 104 nucleotides. 
C)  1 per 1010 nucleotides. 
D)  1 per 1015 nucleotides. 
E)  None of the answers is correct. 
A)  1 per 106 nucleotides. 
B)  1 per 104 nucleotides. 
C)  1 per 1010 nucleotides. 
D)  1 per 1015 nucleotides. 
E)  None of the answers is correct.

Question 18

Common types of mutations that arise in DNA replication include

Accepted Answer

A)  the mismatch of bases in the DNA. 
B)  the deletion of one or more bases in the DNA. 
C)  the insertion of one or more bases in the DNA. 
D)  All the answers are correct. 
E)  the deletion of one or more bases in the DNA and the insertion of one or more bases in the DNA. 
A)  the mismatch of bases in the DNA. 
B)  the deletion of one or more bases in the DNA. 
C)  the insertion of one or more bases in the DNA. 
D)  All the answers are correct. 
E)  the deletion of one or more bases in the DNA and the insertion of one or more bases in the DNA.

Question 19

What assay is used to determine mutagenic potential?

Accepted Answer

A)  Kornberg test 
B)  Okazaki test 
C)  Ames test 
D)  Warburg test 
E)  Ochoa test 
A)  Kornberg test 
B)  Okazaki test 
C)  Ames test 
D)  Warburg test 
E)  Ochoa test

Question 20

The mechanism by which type I topoisomerase relaxes DNA includes which of the following?

Accepted Answer

A)  The OH of Tyr 723 attacks a phosphate group on one DNA strand. 
B)  When the backbone of one strand is cleaved, the DNA rotates. 
C)  ATP binds, leading to a conformation change. 
D)  All the answers are correct. 
E)  The OH of Tyr 723 attacks a phosphate group on one DNA strand, and when the backbone of one strand is cleaved, the DNA rotates. 
A)  The OH of Tyr 723 attacks a phosphate group on one DNA strand. 
B)  When the backbone of one strand is cleaved, the DNA rotates. 
C)  ATP binds, leading to a conformation change. 
D)  All the answers are correct. 
E)  The OH of Tyr 723 attacks a phosphate group on one DNA strand, and when the backbone of one strand is cleaved, the DNA rotates.

Exam 28: DNA Replication, repair, and Recombination

What is DNA gyrase?

DNA polymerase III is able to correct mistakes in replication due to its _________________ function.

Why is shape complementarity so important in DNA replication?

Why is the site of DNA synthesis called the replication fork?

What role does the protein RecA play in recombination?

What does the phrase "recombination of genetic material" refer to?

Huntington's disease is caused by

Which of the following is (are)true?

What is true about DNA polymerases?

Which of the following is a short section of RNA that is extended by DNA polymerase?

What describes the number of times a DNA strand winds around the helix axis when the axis lies in a plane?

How is replication specificity dictated?

Aflatoxin B1 is a compound that is converted to a reactive epoxide by a cytochrome P450 enzyme and causes

How can the leading and lagging strands be synthesized in a coordinated fashion?

The tertiary structures in DNA are created by the process known as ______________.

What name is given to the short sections of DNA found on the lagging strand during DNA synthesis?

The observed error rate in DNA replication is approximately

Common types of mutations that arise in DNA replication include

What assay is used to determine mutagenic potential?

The mechanism by which type I topoisomerase relaxes DNA includes which of the following?

Biochemistry: An Evolving Science

Protein Composition and Structure

Exploring Proteins and Proteomes

DNA, RNA, and the Flow of Genetic Information

Exploring Genes and Genomes

Exploring Evolution and Bioinformatics

Hemoglobin: a Portrait of a Protein in Action

Enzymes: Basic Concepts and Kinetics

Catalytic Strategies

Regulatory Strategies

Carbohydrates

Lipids and Cell Membranes

Membrane Channels and Pumps

Signal-Transduction Pathways

Metabolism: Basic Concepts and Design

Glycolysis and Gluconeogenesis

The Citric Acid Cycle

Oxidative Phosphorylation

The Light Reactions of Photosynthesis

The Calvin Cycle and the Pentose Phosphate Pathway

Glycogen Metabolism

Fatty Acid Metabolism

Protein Turnover and Amino Acid Catabolism

The Biosynthesis of Amino Acids

Nucleotide Biosynthesis

Biosynthesis of Membrane Lipids and Steroids

The Integration of Metabolism

RNA Synthesis and Processing

Protein Synthesis

The Control of Gene Expression in Prokaryotes

The Control of Gene Expression in Eukaryotes

Sensory Systems

The Immune System

Molecular Motors

Drug Development

Filters

Aflatoxin B₁ is a compound that is converted to a reactive epoxide by a cytochrome P450 enzyme and causes