Question 1

Which of the following did Kornberg use to detect DNA synthesis?

Accepted Answer

A) Radioactively labeled E.coli cells 
B) Fluorescently labeled E.coli cells 
C) Radioactively labeled deoxynucleotide triphosphates 
D) Fluorescently labeled deoxynucleotide triphosphates 
E) Nonlabeled deoxynucleotide triphosphates 
A) Radioactively labeled E.coli cells 
B) Fluorescently labeled E.coli cells 
C) Radioactively labeled deoxynucleotide triphosphates 
D) Fluorescently labeled deoxynucleotide triphosphates 
E) Nonlabeled deoxynucleotide triphosphates C

Question 2

How were the sequences that compose the replication origins in yeast discovered?

Accepted Answer

Yeast cells were grown in heavy isotope media to produce denser DNA and then shifted to media with normal,light isotopes.After a few minutes,DNA from these cells was extracted and cut into small pieces.The lighter DNA fragments (which should contain the origins of replication)were collected,fluorescently labeled,and used to hybridize a microarray of yeast sequences.Determination of the sequences to which this light,fluorescently labeled DNA hybridized led to the identification of a number of yeast replication origins.

Question 3

How do the DNA polymerase repair mechanisms work?

Accepted Answer

Both DNA Pol I and DNA Pol III have 3'-to-5' exonuclease activity and can remove nucleotides from the end of a DNA chain as part of an error correction mechanism.If an incorrect base is inserted by DNA polymerase,and the error is recognized immediately,the exonuclease activity excises the erroneous nucleotide from the new strand.After excision,the DNA polymerase resumes motion in the forward direction and inserts the correct nucleotide.

Question 4

What is a replication bubble?

Accepted Answer

A) A complex of replication enzymes on the DNA template strand 
B) A DNA sequence that initiates replication 
C) A tangle of denatured DNA strands near the replication fork 
D) A locally denatured segment of DNA where replication originates 
E) A localized site in the nucleus where chromosomes are replicating 
A) A complex of replication enzymes on the DNA template strand 
B) A DNA sequence that initiates replication 
C) A tangle of denatured DNA strands near the replication fork 
D) A locally denatured segment of DNA where replication originates 
E) A localized site in the nucleus where chromosomes are replicating

Question 5

Why is DNA replication referred to as semiconservative?

Accepted Answer

The progeny double h

Question 6

In Meselson and Stahl's experiment,what kind of DNA molecules would be found after four replication cycles?

Accepted Answer

A) Only heavy DNA (15N-15N) 
B) Only intermediate DNA (15N-14N) 
C) Only light DNA (14N-14N) 
D) Both heavy (15N-15N)and light DNA (14N-14N) 
E) Both heavy (15N-15N)and intermediate DNA (15N-14N) 
A) Only heavy DNA (15N-15N) 
B) Only intermediate DNA (15N-14N) 
C) Only light DNA (14N-14N) 
D) Both heavy (15N-15N)and light DNA (14N-14N) 
E) Both heavy (15N-15N)and intermediate DNA (15N-14N)

Question 7

Which of the following are necessary for DNA replication in vitro?

Accepted Answer

A) RNA,helicase,primers,DNA polymerase 
B) Okazaki fragments,helicase,DNA polymerase 
C) Template DNA,DNA polymerase,four dNTPs,primers,magnesium ions 
D) Template DNA,four dNTPs,magnesium ions 
E) DNA can't replicate in vitro 
A) RNA,helicase,primers,DNA polymerase 
B) Okazaki fragments,helicase,DNA polymerase 
C) Template DNA,DNA polymerase,four dNTPs,primers,magnesium ions 
D) Template DNA,four dNTPs,magnesium ions 
E) DNA can't replicate in vitro

Question 8

The two most basic steps of DNA replication are

Accepted Answer

A) primase causes primer to bind the template and ligase copies the template. 
B) helicase unwinds the template and DNA polymerase binds the template. 
C) leading strand is copied first and lagging strand is copied second. 
D) the new strand is denatured and a template is synthesized. 
E) the template is denatured and a new strand is synthesized. 
A) primase causes primer to bind the template and ligase copies the template. 
B) helicase unwinds the template and DNA polymerase binds the template. 
C) leading strand is copied first and lagging strand is copied second. 
D) the new strand is denatured and a template is synthesized. 
E) the template is denatured and a new strand is synthesized.

Question 9

Topoisomerase and SSB proteins are important components of the replication process in prokaryotes,but they are not found in eukaryotes.

Accepted Answer

A) True 
 B)False

Question 10

At the growing end of a DNA chain,DNA polymerase catalyzes the formation of a disulfide bond between the 3'-OH group of the deoxyribose on the last nucleotide and the 5'-phosphate of the dNTP precursor.

Accepted Answer

A) True 
 B)False

Question 11

DNA primase is an RNA polymerase.

Accepted Answer

A) True 
 B)False

Question 12

After removal of the RNA primers and replacement with DNA nucleotides,the single-stranded nick adjacent to Okazaki fragments is filled in through a reaction that involves which enzyme?

Accepted Answer

A) DNA primase 
B) SSB protein 
C) RNA polymerase 
D) DNA ligase 
E) DNA helicase 
A) DNA primase 
B) SSB protein 
C) RNA polymerase 
D) DNA ligase 
E) DNA helicase

Question 13

What are the differences in replication between leading and lagging strands in terms of continuity and directionality in relation to the replication fork?

Accepted Answer

The leading strand is copied c

Question 14

What experiment demonstrated that the 5'-to-3' exonuclease activity of DNA polymerase I was essential for cell viability?

Accepted Answer

In E.coli,the DNA Pol I polAex1 mutant s

Question 15

The enzymatic activity of a telomerase is best described as a

Accepted Answer

A) polymerase. 
B) ligase. 
C) topoisomerase. 
D) reverse transcriptase. 
E) exonuclease. 
A) polymerase. 
B) ligase. 
C) topoisomerase. 
D) reverse transcriptase. 
E) exonuclease.

Question 16

In eukaryotes,DNA replication begins at a single origin of replication on each chromosome.

Accepted Answer

A) True 
 B)False

Question 17

The base-pairing error rate remains low during replication because

Accepted Answer

A) DNA repair mechanisms can fix the mispaired bases. 
B) bases that are mispaired can excise themselves. 
C) UV light radiation corrects any base mispairs. 
D) mispaired bases cause a cell to die before replication is complete. 
E) None of these; base-pairing errors are not possible 
A) DNA repair mechanisms can fix the mispaired bases. 
B) bases that are mispaired can excise themselves. 
C) UV light radiation corrects any base mispairs. 
D) mispaired bases cause a cell to die before replication is complete. 
E) None of these; base-pairing errors are not possible

Question 18

How did Meselson and Stahl rule out the conservative model of DNA replication using equilibrium density gradient centrifugation?

Accepted Answer

First,they grew E.coli cells in a medium

Question 19

Why is an AT-rich sequence characteristic of DNA replicators in all organisms?

Accepted Answer

AT-rich regions of DNA are rel

Question 20

Which enzyme replaces RNA primers with DNA after elongation?

Accepted Answer

A) DNA polymerase I 
B) DNA polymerase III 
C) RNA polymerase 
D) RNA primase 
E) DNA ligase 
A) DNA polymerase I 
B) DNA polymerase III 
C) RNA polymerase 
D) RNA primase 
E) DNA ligase

Exam 3: DNA Replication

Which of the following did Kornberg use to detect DNA synthesis?

How were the sequences that compose the replication origins in yeast discovered?

How do the DNA polymerase repair mechanisms work?

What is a replication bubble?

Why is DNA replication referred to as semiconservative?

In Meselson and Stahl's experiment,what kind of DNA molecules would be found after four replication cycles?

Which of the following are necessary for DNA replication in vitro?

The two most basic steps of DNA replication are

Topoisomerase and SSB proteins are important components of the replication process in prokaryotes,but they are not found in eukaryotes.

At the growing end of a DNA chain,DNA polymerase catalyzes the formation of a disulfide bond between the 3'-OH group of the deoxyribose on the last nucleotide and the 5'-phosphate of the dNTP precursor.

DNA primase is an RNA polymerase.

After removal of the RNA primers and replacement with DNA nucleotides,the single-stranded nick adjacent to Okazaki fragments is filled in through a reaction that involves which enzyme?

What are the differences in replication between leading and lagging strands in terms of continuity and directionality in relation to the replication fork?

What experiment demonstrated that the 5'-to-3' exonuclease activity of DNA polymerase I was essential for cell viability?

The enzymatic activity of a telomerase is best described as a

In eukaryotes,DNA replication begins at a single origin of replication on each chromosome.

The base-pairing error rate remains low during replication because

How did Meselson and Stahl rule out the conservative model of DNA replication using equilibrium density gradient centrifugation?

Why is an AT-rich sequence characteristic of DNA replicators in all organisms?

Which enzyme replaces RNA primers with DNA after elongation?

Genetics: An Introduction

DNA: The Genetic Material

Gene Function

Gene Expression: Transcription

Gene Expression: Translation

Dna Mutation, DNA Repair, and Transposable Elements

Genomics: The Mapping and Sequencing of Genomes

Functional and Comparative Genomics

Recombinant DNA Technology

Mendelian Genetics

Chromosomal Basis of Inheritance

Extensions of and Deviations From Mendelian Genetic Principles

Genetic Mapping in Eukaryotes

Genetics of Bacteria and Bacteriophages

Variations in Chromosome Structure and Number

Regulation of Gene Expression in Bacteria and Bacteriophages

Regulation of Gene Expression in Eukaryotes

Genetic Analysis of Development

Genetics of Cancer

Population Genetics

Quantitative Genetics

Molecular Evolution

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