Question 1

Which of the following molecular characteristics cause histones to bind tightly to DNA?

Accepted Answer

A)  Histones are positively charged, and DNA is negatively charged. 
B)  Histones are negatively charged, and DNA is positively charged. 
C)  Both histones and DNA are strongly hydrophobic. 
D)  Histones are covalently linked to the DNA. 
A)  Histones are positively charged, and DNA is negatively charged. 
B)  Histones are negatively charged, and DNA is positively charged. 
C)  Both histones and DNA are strongly hydrophobic. 
D)  Histones are covalently linked to the DNA.

Question 2

Which of the following statements correctly describes the difference between ATP and the nucleotides used during DNA synthesis?

Accepted Answer

A)  The nucleotides have the sugar deoxyribose; ATP has the sugar ribose. 
B)  The nucleotides have two phosphate groups; ATP has three phosphate groups. 
C)  ATP contains three high-energy bonds; the nucleotides have two. 
D)  ATP is found only in human cells; the nucleotides are found in all animal and plant cells. 
A)  The nucleotides have the sugar deoxyribose; ATP has the sugar ribose. 
B)  The nucleotides have two phosphate groups; ATP has three phosphate groups. 
C)  ATP contains three high-energy bonds; the nucleotides have two. 
D)  ATP is found only in human cells; the nucleotides are found in all animal and plant cells.

Question 3

Hershey and Chase used a DNA-based virus for their work. How might the results have been different if they had used an RNA virus?

Accepted Answer

A)  With an RNA virus, radioactive protein would have been in the final pellet. 
B)  With an RNA virus, radioactive RNA would have been in the final pellet. 
C)  With an RNA virus, neither sample would have had a radioactive pellet. 
D)  With an RNA virus, the protein shell would have been radioactive in both samples. 
A)  With an RNA virus, radioactive protein would have been in the final pellet. 
B)  With an RNA virus, radioactive RNA would have been in the final pellet. 
C)  With an RNA virus, neither sample would have had a radioactive pellet. 
D)  With an RNA virus, the protein shell would have been radioactive in both samples.

Question 4

Which of the following characteristics would you expect of a eukaryotic organism that lacks the enzyme telomerase?

Accepted Answer

A)  a high probability of somatic cells becoming cancerous 
B)  an inability to produce Okazaki fragments 
C)  an inability to repair thymine dimers 
D)  a reduction in chromosome length in gametes 
A)  a high probability of somatic cells becoming cancerous 
B)  an inability to produce Okazaki fragments 
C)  an inability to repair thymine dimers 
D)  a reduction in chromosome length in gametes

Question 5

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 6

A heat-killed, phosphorescent (light-emitting) strain of bacteria is mixed with a living, non-phosphorescent strain. Further observations of the mixture show that some of the living cells are now phosphorescent. Which of the following observations would provide the best evidence that the ability to phosphoresce is a heritable trait?

Accepted Answer

A)  evidence that DNA was passed from the heat-killed strain to the living strain 
B)  evidence that protein passed from the heat-killed strain to the living strain 
C)  especially bright phosphorescence in the living strain 
D)  phosphorescence in descendants of the living cells 
A)  evidence that DNA was passed from the heat-killed strain to the living strain 
B)  evidence that protein passed from the heat-killed strain to the living strain 
C)  especially bright phosphorescence in the living strain 
D)  phosphorescence in descendants of the living cells

Question 7

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 8

What are telomeres?

Accepted Answer

A)  the structures that hold two sister chromatids together 
B)  enzymes that elongate the DNA strand during replication 
C)  the sites of origin of DNA replication 
D)  the ends of linear chromosomes 
A)  the structures that hold two sister chromatids together 
B)  enzymes that elongate the DNA strand during replication 
C)  the sites of origin of DNA replication 
D)  the ends of linear chromosomes

Question 9

Semiconservative replication involves a template. What is the template?

Accepted Answer

A)  single-stranded binding proteins 
B)  DNA polymerase 
C)  one strand of the DNA molecule 
D)  an RNA molecule 
A)  single-stranded binding proteins 
B)  DNA polymerase 
C)  one strand of the DNA molecule 
D)  an RNA molecule

Question 10

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 11

Researchers found a strain of E. coli bacteria that had mutation rates one hundred times higher than normal. Which of the following statements correctly describes the most likely cause of these results?

Accepted Answer

A)  The single-strand binding proteins were malfunctioning during DNA replication. 
B)  There were one or more base pair mismatches in the RNA primer. 
C)  The proofreading mechanism of DNA polymerase was not working properly. 
D)  The DNA polymerase was unable to add bases to the 3′ end of the growing nucleic acid chain. 
A)  The single-strand binding proteins were malfunctioning during DNA replication. 
B)  There were one or more base pair mismatches in the RNA primer. 
C)  The proofreading mechanism of DNA polymerase was not working properly. 
D)  The DNA polymerase was unable to add bases to the 3′ end of the growing nucleic acid chain.

Question 12

Which of the following statements accurately describes the structure of a eukaryotic chromosome?

Accepted Answer

A)  It is composed of a single strand of DNA. 
B)  It is constructed as a series of nucleosomes wrapped around two DNA molecules. 
C)  It has different numbers of genes in different cell types of an organism. 
D)  It is a single linear molecule of double-stranded DNA plus proteins. 
A)  It is composed of a single strand of DNA. 
B)  It is constructed as a series of nucleosomes wrapped around two DNA molecules. 
C)  It has different numbers of genes in different cell types of an organism. 
D)  It is a single linear molecule of double-stranded DNA plus proteins.

Question 13

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 14

Which of the following structural characteristics is most critical for the association between histones and DNA?

Accepted Answer

A)  Histones are small proteins. 
B)  Histones are highly conserved (that is, histones are very similar in every eukaryote). 
C)  There are at least five different histone proteins in every eukaryote. 
D)  Histones are positively charged. 
A)  Histones are small proteins. 
B)  Histones are highly conserved (that is, histones are very similar in every eukaryote). 
C)  There are at least five different histone proteins in every eukaryote. 
D)  Histones are positively charged.

Question 15

Use the figure to answer the following question.
 
In the late 1950s, Meselson and Stahl grew bacteria in a medium containing "heavy" (radioactive) nitrogen (¹³N) and then transferred them to a medium containing ¹⁴N (non-radioactive). Which of the results in the figure would be expected after one round of DNA replication in the presence of ¹⁴N?

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  D 
A)  A 
B)  B 
C)  C 
D)  D

Question 16

E. coli cells grown on ¹⁵N medium are transferred to ¹⁴N medium and allowed to grow for two more generations (two rounds of DNA replication). DNA extracted from these cells is centrifuged. What density distribution of DNA would you expect in this experiment?

Accepted Answer

A)  one high-density and one low-density band 
B)  one intermediate-density band 
C)  one high-density and one intermediate-density band 
D)  one low-density and one intermediate-density band 
A)  one high-density and one low-density band 
B)  one intermediate-density band 
C)  one high-density and one intermediate-density band 
D)  one low-density and one intermediate-density band

Question 17

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 18

In E. coli, what is the function of DNA polymerase III?

Accepted Answer

A)  to unwind the DNA helix during replication 
B)  to seal together the broken ends of DNA strands 
C)  to add nucleotides to the 3' end of a growing DNA strand 
D)  to degrade damaged DNA molecules 
A)  to unwind the DNA helix during replication 
B)  to seal together the broken ends of DNA strands 
C)  to add nucleotides to the 3' end of a growing DNA strand 
D)  to degrade damaged DNA molecules

Question 19

You briefly expose bacteria undergoing DNA replication to radioactively labeled nucleotides. When you centrifuge the DNA isolated from the bacteria, the DNA separates into two classes. One class of labeled DNA includes very large molecules (thousands or even millions of nucleotides long), and the other includes short stretches of DNA (several hundred to a few thousand nucleotides in length). Which two classes of DNA do these different samples represent?

Accepted Answer

A)  leading strands and Okazaki fragments 
B)  lagging strands and Okazaki fragments 
C)  Okazaki fragments and RNA primers 
D)  leading strands and RNA primers 
A)  leading strands and Okazaki fragments 
B)  lagging strands and Okazaki fragments 
C)  Okazaki fragments and RNA primers 
D)  leading strands and RNA primers

Question 20

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

Exam 16: The Molecular Basis of Inheritance

Which of the following molecular characteristics cause histones to bind tightly to DNA?

Which of the following statements correctly describes the difference between ATP and the nucleotides used during DNA synthesis?

Hershey and Chase used a DNA-based virus for their work. How might the results have been different if they had used an RNA virus?

Which of the following characteristics would you expect of a eukaryotic organism that lacks the enzyme telomerase?

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

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

What are telomeres?

Semiconservative replication involves a template. What is the template?

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

Researchers found a strain of E. coli bacteria that had mutation rates one hundred times higher than normal. Which of the following statements correctly describes the most likely cause of these results?

Which of the following statements accurately describes the structure of a eukaryotic chromosome?

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

Which of the following structural characteristics is most critical for the association between histones and DNA?

E. coli cells grown on ¹⁵N medium are transferred to ¹⁴N medium and allowed to grow for two more generations (two rounds of DNA replication). DNA extracted from these cells is centrifuged. What density distribution of DNA would you expect in this experiment?

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

In E. coli, what is the function of DNA polymerase III?

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

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

Protists

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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