Question 1

How does the enzyme telomerase meet the challenge of replicating the ends of linear chromosomes?

Accepted Answer

A)  It adds a single 5' cap structure that resists degradation by nucleases. 
B)  It causes specific double-strand DNA breaks that result in blunt ends on both strands. 
C)  It catalyzes the lengthening of telomeres, compensating for the shortening that could occur during replication without telomerase activity. 
D)  It adds numerous GC pairs, which resist hydrolysis and maintain chromosome integrity. 
A)  It adds a single 5' cap structure that resists degradation by nucleases. 
B)  It causes specific double-strand DNA breaks that result in blunt ends on both strands. 
C)  It catalyzes the lengthening of telomeres, compensating for the shortening that could occur during replication without telomerase activity. 
D)  It adds numerous GC pairs, which resist hydrolysis and maintain chromosome integrity.

Question 2

Who performed classic experiments that supported the semiconservative model of DNA replication?

Accepted Answer

A)  Watson and Crick 
B)  Meselson and Stahl 
C)  Hershey and Chase 
D)  Franklin and Wilkins 
A)  Watson and Crick 
B)  Meselson and Stahl 
C)  Hershey and Chase 
D)  Franklin and Wilkins

Question 3

Which of the following statements accurately describes the differences between DNA replication in prokaryotes and DNA replication in eukaryotes?

Accepted Answer

A)  Prokaryotic chromosomes have histones, whereas eukaryotic chromosomes do not. 
B)  Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many. 
C)  The rate of elongation during DNA replication is slower in prokaryotes than in eukaryotes. 
D)  Prokaryotes produce Okazaki fragments during DNA replication, but eukaryotes do not. 
A)  Prokaryotic chromosomes have histones, whereas eukaryotic chromosomes do not. 
B)  Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many. 
C)  The rate of elongation during DNA replication is slower in prokaryotes than in eukaryotes. 
D)  Prokaryotes produce Okazaki fragments during DNA replication, but eukaryotes do not.

Question 4

In DNA replication, the resulting daughter molecules contain one strand of the original parental DNA and one new strand. What is the explanation for this phenomenon?

Accepted Answer

A)  DNA replication is semiconservative. 
B)  DNA replication is conservative. 
C)  DNA replication is not conservative. 
D)  RNA synthesis is conservative. 
A)  DNA replication is semiconservative. 
B)  DNA replication is conservative. 
C)  DNA replication is not conservative. 
D)  RNA synthesis is conservative.

Question 5

After the first replication was observed in their experiments testing the nature of DNA replication, Meselson and Stahl could be confident of which of the following conclusions?

Accepted Answer

A)  Replication is semi-conservative. 
B)  Replication is not dispersive. 
C)  Replication is not conservative. 
D)  Replication is neither dispersive nor conservative. 
A)  Replication is semi-conservative. 
B)  Replication is not dispersive. 
C)  Replication is not conservative. 
D)  Replication is neither dispersive nor conservative.

Question 6

Hershey and Chase set out to determine what molecule served as the unit of inheritance. They completed a series of experiments in which E. coli was infected by a T2 virus. Which molecular component of the T2 virus actually ended up inside the cell?

Accepted Answer

A)  protein 
B)  RNA 
C)  ribosome 
D)  DNA 
A)  protein 
B)  RNA 
C)  ribosome 
D)  DNA

Question 7

At a specific area of a chromosome, the sequence of nucleotides below is present where the chain opens to form a replication fork:
3' C C T A G G C T G C A A T C C 5'
An RNA primer is formed starting at the underlined T (T)of the template. Which of the following represents the primer sequence?

Accepted Answer

A)  5' G C C T A G G 3' 
B)  5' A C G T T A G G 3' 
C)  5' A C G U U A G G 3' 
D)  5' G C C U A G G 3' 
A)  5' G C C T A G G 3' 
B)  5' A C G T T A G G 3' 
C)  5' A C G U U A G G 3' 
D)  5' G C C U A G G 3'

Question 8

What is meant by the description "antiparallel" regarding the two strands that make up the DNA double helix?

Accepted Answer

A)  The double helix structure of DNA creates nonparallel strands. 
B)  The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand. 
C)  Base pairings create unequal spacing between the two DNA strands. 
D)  One strand contains only purines and the other contains only pyrimidines. 
A)  The double helix structure of DNA creates nonparallel strands. 
B)  The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand. 
C)  Base pairings create unequal spacing between the two DNA strands. 
D)  One strand contains only purines and the other contains only pyrimidines.

Question 9

What is the role of DNA ligase in the elongation of the lagging strand during DNA replication?

Accepted Answer

A)  It synthesizes RNA nucleotides to make a primer. 
B)  It joins Okazaki fragments together. 
C)  It unwinds the parental double helix. 
D)  It stabilizes the unwound parental DNA. 
A)  It synthesizes RNA nucleotides to make a primer. 
B)  It joins Okazaki fragments together. 
C)  It unwinds the parental double helix. 
D)  It stabilizes the unwound parental DNA.

Question 10

Which of the following statements describes the process of transformation in bacteria?

Accepted Answer

A)  A strand of DNA is created from an RNA molecule. 
B)  A strand of RNA is created from a DNA molecule. 
C)  Bacterial cells are infected by a phage DNA molecule. 
D)  External DNA is taken into a cell, becoming part of the cell's genome. 
A)  A strand of DNA is created from an RNA molecule. 
B)  A strand of RNA is created from a DNA molecule. 
C)  Bacterial cells are infected by a phage DNA molecule. 
D)  External DNA is taken into a cell, becoming part of the cell's genome.

Question 11

A biochemist isolates, purifies, and combines in a test tube a variety of molecules needed for DNA replication. When she adds some DNA to the mixture, replication occurs, but each DNA molecule consists of a normal strand paired with numerous segments of DNA a few hundred nucleotides long. What has she probably left out of the mixture?

Accepted Answer

A)  DNA polymerase 
B)  DNA ligase 
C)  Okazaki fragments 
D)  primase 
A)  DNA polymerase 
B)  DNA ligase 
C)  Okazaki fragments 
D)  primase

Question 12

What is the function of the enzyme topoisomerase in DNA replication?

Accepted Answer

A)  relieving strain in the DNA ahead of the replication fork caused by the untwisting of the double helix 
B)  elongating new DNA at a replication fork by adding nucleotides to the existing chain 
C)  reattaching the hydrogen bonds between the base pairs in the double helix 
D)  building RNA primers using the parental DNA strand as a template 
A)  relieving strain in the DNA ahead of the replication fork caused by the untwisting of the double helix 
B)  elongating new DNA at a replication fork by adding nucleotides to the existing chain 
C)  reattaching the hydrogen bonds between the base pairs in the double helix 
D)  building RNA primers using the parental DNA strand as a template

Question 13

If a cell were unable to produce histone proteins, which of the following results would be a likely effect on the cell?

Accepted Answer

A)  There would be an increase in the amount of DNA produced during replication. 
B)  The cell's DNA could not be packed into its nucleus. 
C)  Spindle fibers would not form during prophase. 
D)  Amplification of other genes would compensate for the lack of histones. 
A)  There would be an increase in the amount of DNA produced during replication. 
B)  The cell's DNA could not be packed into its nucleus. 
C)  Spindle fibers would not form during prophase. 
D)  Amplification of other genes would compensate for the lack of histones.

Question 14

In an analysis of the nucleotide composition of a molecule of DNA, which of the following combinations of base pairs will be found?

Accepted Answer

A)  A = C 
B)  A = G and C = T 
C)  A + C = G + T 
D)  G + C = T + A 
A)  A = C 
B)  A = G and C = T 
C)  A + C = G + T 
D)  G + C = T + A

Question 15

Use the figure to answer the following question.
Single strand as a template plus $3 ^ { \prime }$ end to start DNA synthesis

Referring to the figure, what bases will be added to the primer as DNA replication proceeds?

Accepted Answer

A)  5? C, A, G, C, A, G, A 3? 
B)  3? T, C, T, G, C, T, G 5? 
C)  5? A, G, A, C, G, A, C 3? 
D)  3? G, T, C, G, T, C, T 5? 
A)  5? C, A, G, C, A, G, A 3? 
B)  3? T, C, T, G, C, T, G 5? 
C)  5? A, G, A, C, G, A, C 3? 
D)  3? G, T, C, G, T, C, T 5?

Question 16

Which of the following facts did Hershey and Chase make use of in trying to determine whether DNA or protein is the genetic material?

Accepted Answer

A)  DNA contains sulfur, whereas protein does not. 
B)  DNA contains phosphorus, whereas protein does not. 
C)  DNA contains nitrogen, whereas protein does not. 
D)  DNA contains purines, whereas protein includes pyrimidines. 
A)  DNA contains sulfur, whereas protein does not. 
B)  DNA contains phosphorus, whereas protein does not. 
C)  DNA contains nitrogen, whereas protein does not. 
D)  DNA contains purines, whereas protein includes pyrimidines.

Question 17

Suppose you are provided with an actively dividing culture of E. coli bacteria to which radioactive thymine has been added. What would happen if a cell replicates once in the presence of this radioactive base?

Accepted Answer

A)  One of the daughter cells, but not the other, would have radioactive DNA. 
B)  Neither of the two daughter cells would be radioactive. 
C)  All four bases of the DNA would be radioactive. 
D)  DNA in both daughter cells would be radioactive. 
A)  One of the daughter cells, but not the other, would have radioactive DNA. 
B)  Neither of the two daughter cells would be radioactive. 
C)  All four bases of the DNA would be radioactive. 
D)  DNA in both daughter cells would be radioactive.

Question 18

The elongation of the leading strand during DNA synthesis

Accepted Answer

A)  progresses away from the replication fork. 
B)  occurs in the 3′ → 5′ direction. 
C)  produces Okazaki fragments. 
D)  depends on the action of DNA polymerase. 
A)  progresses away from the replication fork. 
B)  occurs in the 3′ → 5′ direction. 
C)  produces Okazaki fragments. 
D)  depends on the action of DNA polymerase.

Question 19

In analyzing the number of different bases in a DNA sample, which result would be consistent with the base-pairing rules?

Accepted Answer

A)  A = G 
B)  A + G = C + T 
C)  A + T = G + C 
D)  A = C 
A)  A = G 
B)  A + G = C + T 
C)  A + T = G + C 
D)  A = C

Question 20

Individuals with the disorder xeroderma pigmentosum are hypersensitive to sunlight, and mutations to the DNA in their skin cells are left uncorrected. Why are the mutations not corrected in individuals with this disorder?

Accepted Answer

A)  The disorder makes cells unable to replicate DNA. 
B)  The disorder causes mitosis to stop during metaphase. 
C)  The disorder makes cells unable to form chromosomes. 
D)  The disorder causes cells to be unable to repair thymine dimers. 
A)  The disorder makes cells unable to replicate DNA. 
B)  The disorder causes mitosis to stop during metaphase. 
C)  The disorder makes cells unable to form chromosomes. 
D)  The disorder causes cells to be unable to repair thymine dimers.

Exam 16: The Molecular Basis of Inheritance

How does the enzyme telomerase meet the challenge of replicating the ends of linear chromosomes?

Who performed classic experiments that supported the semiconservative model of DNA replication?

Which of the following statements accurately describes the differences between DNA replication in prokaryotes and DNA replication in eukaryotes?

In DNA replication, the resulting daughter molecules contain one strand of the original parental DNA and one new strand. What is the explanation for this phenomenon?

After the first replication was observed in their experiments testing the nature of DNA replication, Meselson and Stahl could be confident of which of the following conclusions?

Hershey and Chase set out to determine what molecule served as the unit of inheritance. They completed a series of experiments in which E. coli was infected by a T2 virus. Which molecular component of the T2 virus actually ended up inside the cell?

At a specific area of a chromosome, the sequence of nucleotides below is present where the chain opens to form a replication fork: 3' C C T A G G C T G C A A T C C 5' An RNA primer is formed starting at the underlined T (T)of the template. Which of the following represents the primer sequence?

What is meant by the description "antiparallel" regarding the two strands that make up the DNA double helix?

What is the role of DNA ligase in the elongation of the lagging strand during DNA replication?

Which of the following statements describes the process of transformation in bacteria?

What is the function of the enzyme topoisomerase in DNA replication?

If a cell were unable to produce histone proteins, which of the following results would be a likely effect on the cell?

In an analysis of the nucleotide composition of a molecule of DNA, which of the following combinations of base pairs will be found?

Use the figure to answer the following question. Single strand as a template plus 3′3 ^ { \prime }3′ end to start DNA synthesis Referring to the figure, what bases will be added to the primer as DNA replication proceeds?

Which of the following facts did Hershey and Chase make use of in trying to determine whether DNA or protein is the genetic material?

Suppose you are provided with an actively dividing culture of E. coli bacteria to which radioactive thymine has been added. What would happen if a cell replicates once in the presence of this radioactive base?

The elongation of the leading strand during DNA synthesis

In analyzing the number of different bases in a DNA sample, which result would be consistent with the base-pairing rules?

Individuals with the disorder xeroderma pigmentosum are hypersensitive to sunlight, and mutations to the DNA in their skin cells are left uncorrected. Why are the mutations not corrected in individuals with this disorder?

Evolution, the Themes of Biology, and Scientific Inquiry

The Chemical Context of Life

Water and Life

Carbon and the Molecular Diversity of Life

The Structure and Function of Large Biological Molecules

A Tour of the Cell

Membrane Structure and Function

An Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

Cell Communication

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

Gene Expression: From Gene to Protein

Regulation of Gene Expression

Viruses

DNA Tools and Biotechnology

Genomes and Their Evolution

Descent with Modification: A Darwinian View of Life

The Evolution of Populations

The Origin of Species

The History of Life on Earth

Phylogeny and the Tree of Life

Bacteria and Archaea

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Plant Diversity I: How Plants Colonized Land

Plant Diversity II: The Evolution of Seed Plants

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An Overview of Animal Diversity

An Introduction to Invertebrates

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Resource Acquisition and Transport in Vascular Plants

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Plant Responses to Internal and External Signals

Basic Principles of Animal Form and Function

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Osmoregulation and Excretion

Hormones and the Endocrine System

Animal Reproduction

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Neurons, Synapses, and Signaling

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