Question 1

Which of the following statements correctly describes one characteristic of histones?

Accepted Answer

A) Each nucleosome consists of two histones. 
B) Each nucleosome consists of eight histones. 
C) The carboxyl end of each histone extends outward from the nucleosome and is called a "histone tail." 
D) Histones are found in mammals but not in other eukaryotes. 
A) Each nucleosome consists of two histones. 
B) Each nucleosome consists of eight histones. 
C) The carboxyl end of each histone extends outward from the nucleosome and is called a "histone tail." 
D) Histones are found in mammals but not in other eukaryotes. B

Question 2

In a nucleosome,the DNA is wrapped around

Accepted Answer

A) polymerase molecules. 
B) ribosomes. 
C) histones. 
D) a thymine dimer. 
A) polymerase molecules. 
B) ribosomes. 
C) histones. 
D) a thymine dimer. C

Question 3

Individuals with the disorder xeroderma pigmentosum are hypersensitive to sunlight.What function is impaired in their cells?

Accepted Answer

A) They cannot replicate DNA. 
B) They cannot undergo mitosis. 
C) They cannot exchange DNA with other cells. 
D) They cannot repair thymine dimers. 
A) They cannot replicate DNA. 
B) They cannot undergo mitosis. 
C) They cannot exchange DNA with other cells. 
D) They cannot repair thymine dimers. D

Question 4

Which of the following sequences in double-stranded DNA is most likely to be recognized as a cutting site for a restriction enzyme?

Accepted Answer

A) AAGG TTCC 
B) GGCC CCGG 
C) ACCA TGGT 
D) AAAA TTTT 
A) AAGG TTCC 
B) GGCC CCGG 
C) ACCA TGGT 
D) AAAA TTTT

Question 5

A mutation is identified in a single-celled eukaryote called a protist in which DNA primase does not assemble RNA primers on the lagging strand during DNA replication.Which of the following statements correctly describes a possible result of this mutation?

Accepted Answer

A) DNA replication will proceed normally. 
B) The leading strand will not be replicated normally. 
C) The lagging strand will continue to be replicated normally. 
D) The lagging strand will not be replicated normally. 
A) DNA replication will proceed normally. 
B) The leading strand will not be replicated normally. 
C) The lagging strand will continue to be replicated normally. 
D) The lagging strand will not be replicated normally.

Question 6

Suppose you are provided with an actively dividing culture of Escherichia 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 7

Which of the following statements correctly describes one difference between heterochromatin and euchromatin?

Accepted Answer

A) Heterochromatin is composed of DNA,whereas euchromatin is made of DNA and RNA. 
B) Heterochromatin is found in the cytoplasm while euchromatin is found in the nucleus. 
C) Heterochromatin is highly condensed,whereas euchromatin is less compact. 
D) Euchromatin is not transcribed,whereas heterochromatin is transcribed. 
A) Heterochromatin is composed of DNA,whereas euchromatin is made of DNA and RNA. 
B) Heterochromatin is found in the cytoplasm while euchromatin is found in the nucleus. 
C) Heterochromatin is highly condensed,whereas euchromatin is less compact. 
D) Euchromatin is not transcribed,whereas heterochromatin is transcribed.

Question 8

How does a bacterial cell protect its own DNA from restriction enzymes?

Accepted Answer

A) by adding methyl groups to adenines and cytosines 
B) by using DNA ligase to seal the bacterial DNA into a closed circle 
C) by adding histones to protect the double-stranded DNA 
D) by forming "sticky ends" of bacterial DNA to prevent the enzyme from attaching 
A) by adding methyl groups to adenines and cytosines 
B) by using DNA ligase to seal the bacterial DNA into a closed circle 
C) by adding histones to protect the double-stranded DNA 
D) by forming "sticky ends" of bacterial DNA to prevent the enzyme from attaching

Question 9

A eukaryotic gene has "sticky ends" produced by the restriction endonuclease EcoRI.The gene is added to a mixture containing EcoRI and a bacterial plasmid that carries two genes conferring resistance to the antibiotics ampicillin and tetracycline.The plasmid has one recognition site for EcoRI located in the tetracycline resistance gene.This mixture is incubated for several hours,exposed to DNA ligase,and then added to bacteria growing in nutrient broth.The bacteria are allowed to grow overnight and are streaked on a plate using a technique that produces isolated colonies that are clones of the original.Samples of these colonies are then grown in four different media: nutrient broth plus ampicillin,nutrient broth plus tetracycline,nutrient broth plus ampicillin and tetracycline,and nutrient broth without antibiotics.
Bacteria that contain the plasmid,but not the eukaryotic gene,would grow in which of the following conditions?

Accepted Answer

A) in the nutrient broth plus ampicillin,but not in the broth containing tetracycline 
B) only in the broth containing both antibiotics 
C) in the broth containing tetracycline,but not in the broth containing ampicillin 
D) in all four types of broth 
A) in the nutrient broth plus ampicillin,but not in the broth containing tetracycline 
B) only in the broth containing both antibiotics 
C) in the broth containing tetracycline,but not in the broth containing ampicillin 
D) in all four types of broth

Question 10

Which of the following mechanisms removes nucleotides that are paired incorrectly during DNA replication?

Accepted Answer

A) nucleotide excision repair 
B) chromosomal breakage repair 
C) mismatch repair 
D) telomerase activity 
A) nucleotide excision repair 
B) chromosomal breakage repair 
C) mismatch repair 
D) telomerase activity

Question 11

A eukaryotic gene has "sticky ends" produced by the restriction endonuclease EcoRI.The gene is added to a mixture containing EcoRI and a bacterial plasmid that carries two genes conferring resistance to the antibiotics ampicillin and tetracycline.The plasmid has one recognition site for EcoRI located in the tetracycline resistance gene.This mixture is incubated for several hours,exposed to DNA ligase,and then added to bacteria growing in nutrient broth.The bacteria are allowed to grow overnight and are streaked on a plate using a technique that produces isolated colonies that are clones of the original.Samples of these colonies are then grown in four different media: nutrient broth plus ampicillin,nutrient broth plus tetracycline,nutrient broth plus ampicillin and tetracycline,and nutrient broth without antibiotics.
Bacteria that do not take up any plasmids would grow on which media?

Accepted Answer

A) the nutrient broth only 
B) the nutrient broth and the tetracycline broth 
C) the nutrient broth and the ampicillin broth 
D) the tetracycline broth and the ampicillin broth 
A) the nutrient broth only 
B) the nutrient broth and the tetracycline broth 
C) the nutrient broth and the ampicillin broth 
D) the tetracycline broth and the ampicillin broth

Question 12

During DNA replication,which of the following enzymes separates the DNA strands during replication?

Accepted Answer

A) helicase 
B) DNA polymerase III 
C) ligase 
D) DNA polymerase I 
A) helicase 
B) DNA polymerase III 
C) ligase 
D) DNA polymerase I

Question 13

If a cell were unable to produce histone proteins,which of the following effects would likely occur?

Accepted Answer

A) The cell's DNA couldn't be packed into its nucleus. 
B) Spindle fibers would not form during prophase. 
C) Expression of other genes would compensate for the lack of histones. 
D) DNA polymerase I would not function properly. 
A) The cell's DNA couldn't be packed into its nucleus. 
B) Spindle fibers would not form during prophase. 
C) Expression of other genes would compensate for the lack of histones. 
D) DNA polymerase I would not function properly.

Question 14

Which of the following modifications is most likely to alter the rate at which a DNA fragment moves through a gel during electrophoresis?

Accepted Answer

A) altering the nucleotide sequence of the DNA fragment without adding or removing nucleotides 
B) radioactively labeling the cytosine bases within the DNA fragment 
C) increasing the length of the DNA fragment 
D) leaving the length of the DNA fragment the same 
A) altering the nucleotide sequence of the DNA fragment without adding or removing nucleotides 
B) radioactively labeling the cytosine bases within the DNA fragment 
C) increasing the length of the DNA fragment 
D) leaving the length of the DNA fragment the same

Question 15

The spontaneous loss of amino groups from adenine in DNA results in hypoxanthine,an uncommon base,opposite thymine.What combination of proteins could repair such damage?

Accepted Answer

A) nuclease,DNA polymerase,DNA ligase 
B) topoisomerase,primase,DNA polymerase 
C) topoisomerase,helicase,single-strand binding protein 
D) DNA ligase,replication fork proteins,adenylyl cyclase 
A) nuclease,DNA polymerase,DNA ligase 
B) topoisomerase,primase,DNA polymerase 
C) topoisomerase,helicase,single-strand binding protein 
D) DNA ligase,replication fork proteins,adenylyl cyclase

Question 16

Which type of enzyme was used to produce the DNA molecule in the figure above?

Accepted Answer

A) ligase 
B) a restriction enzyme 
C) RNA polymerase 
D) DNA polymerase 
A) ligase 
B) a restriction enzyme 
C) RNA polymerase 
D) DNA polymerase

Question 17

What is meant by the description "antiparallel" regarding the two strands of nucleic acids that make up DNA?

Accepted Answer

A) The twisting nature 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 twisting nature 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 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

During DNA replication,which of the following enzymes covalently connects segments of DNA?

Accepted Answer

A) helicase 
B) DNA polymerase III 
C) ligase 
D) DNA polymerase I 
A) helicase 
B) DNA polymerase III 
C) ligase 
D) DNA polymerase I

Question 20

Cytosine makes up 42% of the nucleotides in a sample of DNA from an organism.Approximately what percentage of the nucleotides in this sample will be thymine?

Accepted Answer

A) 8% 
B) 16% 
C) 31% 
D) 42% 
A) 8% 
B) 16% 
C) 31% 
D) 42%

Exam 13: The Molecular Basis of Inheritance

Which of the following statements correctly describes one characteristic of histones?

In a nucleosome,the DNA is wrapped around

Individuals with the disorder xeroderma pigmentosum are hypersensitive to sunlight.What function is impaired in their cells?

Which of the following sequences in double-stranded DNA is most likely to be recognized as a cutting site for a restriction enzyme?

A mutation is identified in a single-celled eukaryote called a protist in which DNA primase does not assemble RNA primers on the lagging strand during DNA replication.Which of the following statements correctly describes a possible result of this mutation?

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

Which of the following statements correctly describes one difference between heterochromatin and euchromatin?

How does a bacterial cell protect its own DNA from restriction enzymes?

Which of the following mechanisms removes nucleotides that are paired incorrectly during DNA replication?

During DNA replication,which of the following enzymes separates the DNA strands during replication?

If a cell were unable to produce histone proteins,which of the following effects would likely occur?

Which of the following modifications is most likely to alter the rate at which a DNA fragment moves through a gel during electrophoresis?

The spontaneous loss of amino groups from adenine in DNA results in hypoxanthine,an uncommon base,opposite thymine.What combination of proteins could repair such damage?

Which type of enzyme was used to produce the DNA molecule in the figure above?

What is meant by the description "antiparallel" regarding the two strands of nucleic acids that make up DNA?

The elongation of the leading strand during DNA synthesis

During DNA replication,which of the following enzymes covalently connects segments of DNA?

Cytosine makes up 42% of the nucleotides in a sample of DNA from an organism.Approximately what percentage of the nucleotides in this sample will be thymine?

Introduction: Evolution and the Foundations of Biology

The Chemical Context of Life

Carbon and the Molecular Diversity of Life

A Tour of the Cell

Membrane Transport and Cell Signaling

An Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

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

Development,stem Cells,and Cancer

Viruses

Genomes and Their Evolution

Descent With Modification

Phylogeny

The Evolution of Populations

The Origin of Species

Broad Patterns of Evolution

Early Life and the Diversification of Prokaryotes

The Origin and Diversification of Eukaryotes

The Colonization of Land by Plants and Fungi

The Rise of Animal Diversity

Plant Structure and Growth

Resource Acquisition,nutrition,and Transport in Vascular Plants

Reproduction and Domestication of Flowering Plants

Plant Responses to Internal and External Signals

Homeostasis and Endocrine Signaling

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Reproduction and Development

Neurons,synapses,and Signaling

Nervous and Sensory Systems

Motor Mechanisms and Behavior

Population Ecology and the Distribution of Organisms

Ecological Communities

Ecosystems and Energy

Conservation Biology and Global Change

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