Question 1

RNA primers are synthesized about once every .

Accepted Answer

A)  millisecond 
B)  second 
C)  minute 
D)  40 minutes 
A)  millisecond 
B)  second 
C)  minute 
D)  40 minutes

Question 2

The 3ʹ → 5ʹ exonuclease activity of E. coli DNA polymerase III accounts for the of polymerization.

Accepted Answer

A)  low error rate 
B)  high speed 
C)  directionality 
D)  All of the above 
A)  low error rate 
B)  high speed 
C)  directionality 
D)  All of the above

Question 3

In a sequencing gel, all fragment in one of the four lanes terminates in the same type of nucleotide base.

Accepted Answer

A) True 
 B)False

Question 4

At one point during DNA recombination in E. coli there is formation of a triple-stranded DNA.

Accepted Answer

A) True 
 B)False

Question 5

DNA polymerase III requires a/an for synthesis of DNA to occur.

Accepted Answer

A)  DNA template 
B)  RNA primer 
C)  free 3ʹ-OH end of a DNA strand 
D)  All of the above 
A)  DNA template 
B)  RNA primer 
C)  free 3ʹ-OH end of a DNA strand 
D)  All of the above

Question 6

In the Sanger method for DNA sequencing, the gels are read from bottom to top, since the smallest fragments travel farthest in the sequencing gel.

Accepted Answer

A) True 
 B)False

Question 7

DNA is the only cell macromolecule that can be repaired.

Accepted Answer

A) True 
 B)False

Question 8

Which is not part of the replisome?

Accepted Answer

A)  helicase DnaB 
B)  the primosome 
C)  gyrase 
D)  single-stranded binding protein 
A)  helicase DnaB 
B)  the primosome 
C)  gyrase 
D)  single-stranded binding protein

Question 9

The RNA primer at the beginning of each Okazaki fragment is removed by

Accepted Answer

A)  DNA polymerase I. 
B)  DNA polymerase II. 
C)  DNA polymerase III. 
D)  3ʹ → 5ʹ exonuclease subunit of DNA polymerase III. 
A)  DNA polymerase I. 
B)  DNA polymerase II. 
C)  DNA polymerase III. 
D)  3ʹ → 5ʹ exonuclease subunit of DNA polymerase III.

Question 10

Which of the following is mismatched?

Accepted Answer

A)  ter : Tus 
B)  dnaA : DnaA 
C)  Ori : primer 
D)  Tus : helicase inhibitor 
A)  ter : Tus 
B)  dnaA : DnaA 
C)  Ori : primer 
D)  Tus : helicase inhibitor

Question 11

Fragments on the lagging strand are joined by the enzyme .

Accepted Answer

A)  DNA polymerase I 
B)  DNA synthase 
C)  DNA primosome 
D)  DNA ligase 
A)  DNA polymerase I 
B)  DNA synthase 
C)  DNA primosome 
D)  DNA ligase

Question 12

What is a Klenow fragment?

Accepted Answer

A)  A fragment of DNA polymerase I that lacks 5ʹ → 3ʹ exonuclease activity. 
B)  A topoisomerase responsible for unwinding DNA at the replication fork. 
C)  A portion of the replisome responsible for RNA primer synthesis. 
D)  Short stretches of DNA formed during polymerization of the lagging strand. 
A)  A fragment of DNA polymerase I that lacks 5ʹ → 3ʹ exonuclease activity. 
B)  A topoisomerase responsible for unwinding DNA at the replication fork. 
C)  A portion of the replisome responsible for RNA primer synthesis. 
D)  Short stretches of DNA formed during polymerization of the lagging strand.

Question 13

Which is not an activity for DNA polymerase I?

Accepted Answer

A)  5ʹ → 3ʹ polymerase activity 
B)  joining of Okazaki fragments 
C)  5ʹ → 3ʹ exonuclease activity 
D)  nick translation 
E)  3ʹ → 5ʹ proofreading activity 
A)  5ʹ → 3ʹ polymerase activity 
B)  joining of Okazaki fragments 
C)  5ʹ → 3ʹ exonuclease activity 
D)  nick translation 
E)  3ʹ → 5ʹ proofreading activity

Question 14

It takes about the same amount of time for eukaryotic chromosomes to be replicated in vivo as it does for E. coli. Why is this true?

Accepted Answer

A)  Eukaryotes have multiple origins of replication; E. coli has one unique origin. 
B)  Most chromosomes are approximately the same size. 
C)  Eukaryotic replication occurs at a faster rate, enabling replication of the larger chromosomes in about the same amount of time. 
D)  The replication of DNA in eukaryotes is faster due to a quicker, more accurate repair of mismatches. 
A)  Eukaryotes have multiple origins of replication; E. coli has one unique origin. 
B)  Most chromosomes are approximately the same size. 
C)  Eukaryotic replication occurs at a faster rate, enabling replication of the larger chromosomes in about the same amount of time. 
D)  The replication of DNA in eukaryotes is faster due to a quicker, more accurate repair of mismatches.

Question 15

The protein machine that carries out DNA replication is called .

Accepted Answer

A)  DNA polymerase 
B)  the replication fork 
C)  the Klenow fragment 
D)  the replisome 
A)  DNA polymerase 
B)  the replication fork 
C)  the Klenow fragment 
D)  the replisome

Question 16

What is a reasonable length for an RNA primer in E. coli?

Accepted Answer

A)  a few nucleotides 
B)  50 nucleotides 
C)  100 nucleotides 
D)  1000 nucleotides 
A)  a few nucleotides 
B)  50 nucleotides 
C)  100 nucleotides 
D)  1000 nucleotides

Question 17

Sanger DNA sequencing requires inhibition of DNA polymerization by a specific dideoxynucleoside every time it is copied in the replication process.

Accepted Answer

A) True 
 B)False

Question 18

The processivity of E. coli DNA polymerase III holoenzyme accounts for all of the following except

Accepted Answer

A)  the relatively small number of enzymes needed to replicate the entire chromosome. 
B)  the directionality of polymerization. 
C)  the rapid rate of polymerization. 
D)  the ability of a single holoenzyme to add many nucleotides to a growing DNA chain. 
A)  the relatively small number of enzymes needed to replicate the entire chromosome. 
B)  the directionality of polymerization. 
C)  the rapid rate of polymerization. 
D)  the ability of a single holoenzyme to add many nucleotides to a growing DNA chain.

Question 19

Approximately base pairs are added per second during DNA in vivo replication in E. coli.

Accepted Answer

A)  10 
B)  100 
C)  1000 
D)  1,000,000 
A)  10 
B)  100 
C)  1000 
D)  1,000,000

Question 20

Why is DNA damage in skin cells from exposure to excessive UV light not completely reversed by photoreactivation?

Accepted Answer

A)  DNA photolyase in humans is activated only under conditions of heat shock. 
B)  Humans lack a photoreactivation repair mechanism. 
C)  The presence of histones greatly slows photoreactivation, thus humans depends primarily on other forms of DNA repair. 
D)  Photoreactivation is specific for the removal of thymine dimers. Thymine dimers do not form in human DNA. 
A)  DNA photolyase in humans is activated only under conditions of heat shock. 
B)  Humans lack a photoreactivation repair mechanism. 
C)  The presence of histones greatly slows photoreactivation, thus humans depends primarily on other forms of DNA repair. 
D)  Photoreactivation is specific for the removal of thymine dimers. Thymine dimers do not form in human DNA.

Exam 20: Dna Replication, Repair, and Recombination

RNA primers are synthesized about once every .

The 3ʹ → 5ʹ exonuclease activity of E. coli DNA polymerase III accounts for the of polymerization.

In a sequencing gel, all fragment in one of the four lanes terminates in the same type of nucleotide base.

At one point during DNA recombination in E. coli there is formation of a triple-stranded DNA.

DNA polymerase III requires a/an for synthesis of DNA to occur.

In the Sanger method for DNA sequencing, the gels are read from bottom to top, since the smallest fragments travel farthest in the sequencing gel.

DNA is the only cell macromolecule that can be repaired.

Which is not part of the replisome?

The RNA primer at the beginning of each Okazaki fragment is removed by

Which of the following is mismatched?

Fragments on the lagging strand are joined by the enzyme .

What is a Klenow fragment?

Which is not an activity for DNA polymerase I?

It takes about the same amount of time for eukaryotic chromosomes to be replicated in vivo as it does for E. coli. Why is this true?

The protein machine that carries out DNA replication is called .

What is a reasonable length for an RNA primer in E. coli?

Sanger DNA sequencing requires inhibition of DNA polymerization by a specific dideoxynucleoside every time it is copied in the replication process.

The processivity of E. coli DNA polymerase III holoenzyme accounts for all of the following except

Approximately base pairs are added per second during DNA in vivo replication in E. coli.

Why is DNA damage in skin cells from exposure to excessive UV light not completely reversed by photoreactivation?

Introduction to Biochemistry

Water

Amino Acids and the Primary Structures of Proteins

Proteins: Three-Dimensional Structure and Function

Properties of Enzymes

Mechanisms of Enzymes

Coenzymes and Vitamins

Carbohydrates

Lipids and Membranes

Introduction to Metabolism

Glycolysis

Gluconeogenesis, the Pentose Phosphate Pathway, and Glycogen Metabolism

The Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Lipid Metabolism

Amino Acid Metabolism

Nucleotide Metabolism

Nucleic Acids

Transcription and Rna Processing

Protein Synthesis

Recombinant Dna Technology

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