Question 1

Which of the following processes within viral replication is the greatest source of genetic variation in RNA virus populations?

Accepted Answer

A)  High mutation rate due to lack of proofreading of RNA genome replication errors. 
B)  Transcription from the host cell RNA polymerase introduces numerous mutations. 
C)  Capsid proteins from the host cell can replace the viral capsid. 
D)  Viral RNA is translated by host cell ribosomes. 
A)  High mutation rate due to lack of proofreading of RNA genome replication errors. 
B)  Transcription from the host cell RNA polymerase introduces numerous mutations. 
C)  Capsid proteins from the host cell can replace the viral capsid. 
D)  Viral RNA is translated by host cell ribosomes. A

Question 2

RNA viruses require their own supply of certain enzymes because

Accepted Answer

A)  host cells rapidly destroy the viruses. 
B)  host cells lack enzymes that can replicate the viral genome. 
C)  these enzymes translate viral mRNA into proteins. 
D)  these enzymes penetrate host cell membranes. 
A)  host cells rapidly destroy the viruses. 
B)  host cells lack enzymes that can replicate the viral genome. 
C)  these enzymes translate viral mRNA into proteins. 
D)  these enzymes penetrate host cell membranes. B

Question 3

The difference between vertical and horizontal transmission of plant viruses is that vertical transmission is ________.

Accepted Answer

A)  transmission of a virus from a parent plant to its progeny, and horizontal transmission is one plant spreading the virus to another plant 
B)  the spread of viruses from upper leaves to lower leaves of the plant, and horizontal transmission is the spread of a virus among leaves at the same general level 
C)  the spread of viruses from trees and tall plants to bushes and other smaller plants, and horizontal transmission is the spread of viruses among plants of similar size 
D)  the transfer of DNA from a plant of one species to a plant of a different species, and horizontal transmission is the spread of viruses among plants of the same species 
A)  transmission of a virus from a parent plant to its progeny, and horizontal transmission is one plant spreading the virus to another plant 
B)  the spread of viruses from upper leaves to lower leaves of the plant, and horizontal transmission is the spread of a virus among leaves at the same general level 
C)  the spread of viruses from trees and tall plants to bushes and other smaller plants, and horizontal transmission is the spread of viruses among plants of similar size 
D)  the transfer of DNA from a plant of one species to a plant of a different species, and horizontal transmission is the spread of viruses among plants of the same species A

Question 4

A researcher lyses a cell that contains nucleic acid molecules and capsomeres of tobacco mosaic virus (TMV). The cell contents are left in a covered test tube overnight. The next day this mixture is sprayed on tobacco plants. What would you expect to happen to the plants that were sprayed with the mixture?

Accepted Answer

A)  The plants would develop some but not all of the symptoms of the TMV infection. 
B)  The plants would develop the typical symptoms of TMV infection. 
C)  The plants would not show any disease symptoms. 
D)  The plants would become infected, but extracts from these plants would be unable to infect other plants. 
A)  The plants would develop some but not all of the symptoms of the TMV infection. 
B)  The plants would develop the typical symptoms of TMV infection. 
C)  The plants would not show any disease symptoms. 
D)  The plants would become infected, but extracts from these plants would be unable to infect other plants.

Question 5

Why do RNA viruses appear to have higher rates of mutation?

Accepted Answer

A)  RNA nucleotides are more unstable than DNA nucleotides. 
B)  Replication of their genomes does not involve proofreading. 
C)  RNA viruses can incorporate a variety of nonstandard bases. 
D)  RNA viruses are more sensitive to mutagens. 
A)  RNA nucleotides are more unstable than DNA nucleotides. 
B)  Replication of their genomes does not involve proofreading. 
C)  RNA viruses can incorporate a variety of nonstandard bases. 
D)  RNA viruses are more sensitive to mutagens.

Question 6

A population of viruses with similar characteristics is called a ________.

Accepted Answer

A)  class 
B)  species 
C)  type 
D)  genome 
A)  class 
B)  species 
C)  type 
D)  genome

Question 7

Which of the following statements supports the argument that viruses are nonliving?

Accepted Answer

A)  They do not carry out metabolic processes. 
B)  Their DNA does not encode proteins. 
C)  They have RNA rather than DNA. 
D)  They do not evolve. 
A)  They do not carry out metabolic processes. 
B)  Their DNA does not encode proteins. 
C)  They have RNA rather than DNA. 
D)  They do not evolve.

Question 8

Which of the following statements is correct regarding viral infections in plants?

Accepted Answer

A)  They can be controlled with antibiotics. 
B)  They can spread within a plant via plasmodesmata. 
C)  They have little effect on plant growth. 
D)  They are not spread by animals. 
A)  They can be controlled with antibiotics. 
B)  They can spread within a plant via plasmodesmata. 
C)  They have little effect on plant growth. 
D)  They are not spread by animals.

Question 9

What is difference between an epidemic and a pandemic?

Accepted Answer

A)  An epidemic is a disease; a pandemic is a treatment. 
B)  An epidemic is restricted to a local region; a pandemic is global. 
C)  An epidemic has low mortality; a pandemic has higher mortality. 
D)  An epidemic is caused by a bacterial infection; a pandemic is caused by a viral infection. 
A)  An epidemic is a disease; a pandemic is a treatment. 
B)  An epidemic is restricted to a local region; a pandemic is global. 
C)  An epidemic has low mortality; a pandemic has higher mortality. 
D)  An epidemic is caused by a bacterial infection; a pandemic is caused by a viral infection.

Question 10

Use the following information to answer the question.
The herpes viruses are important enveloped DNA viruses that cause disease in vertebrates and in some invertebrates such as oysters. Some of the human forms are herpes simplex virus (HSV) types I and II, causing facial and genital lesions, and the varicella zoster virus (VSV), causing chicken pox and shingles. Each of these three actively infects nervous tissue. Primary infections are fairly mild, but the virus is not then cleared from the host; rather, viral genomes are maintained in cells in a latent phase. The virus can later reactivate, replicate again, and infect others.
If scientists are trying to use what they know about the herpes simplex virus to devise a means of protecting other people from being infected, which of the following treatments would have the best chance of lowering the number of new cases of infection?

Accepted Answer

A)  Vaccinate of all persons with preexisting cases of herpes simplex virus. 
B)  Interfere with new viral replication in preexisting cases of herpes simplex virus. 
C)  Treat herpes simplex virus lesions to shorten the breakout. 
D)  Educate people about avoiding sources of infection. 
A)  Vaccinate of all persons with preexisting cases of herpes simplex virus. 
B)  Interfere with new viral replication in preexisting cases of herpes simplex virus. 
C)  Treat herpes simplex virus lesions to shorten the breakout. 
D)  Educate people about avoiding sources of infection.

Question 11

What are prions?

Accepted Answer

A)  mobile segments of DNA 
B)  tiny circular molecules of RNA that can infect plants 
C)  viral DNA that attaches itself to the host genome and causes disease 
D)  misfolded versions of normal proteins that can cause disease 
A)  mobile segments of DNA 
B)  tiny circular molecules of RNA that can infect plants 
C)  viral DNA that attaches itself to the host genome and causes disease 
D)  misfolded versions of normal proteins that can cause disease

Question 12

In many ways, the regulation of the genes of a particular group of viruses will be similar to the regulation of the host genes. Therefore, which of the following regulation mechanisms would you expect of the genes of a bacteriophage?

Accepted Answer

A)  regulation via acetylation of histones 
B)  positive control mechanisms rather than negative 
C)  control of more than one gene in an operon 
D)  reliance on transcription activators 
A)  regulation via acetylation of histones 
B)  positive control mechanisms rather than negative 
C)  control of more than one gene in an operon 
D)  reliance on transcription activators

Question 13

Which of the following statements accurately describes the lysogenic cycle of lambda (λ) phage?

Accepted Answer

A)  After infection, the viral genes immediately turn the host cell into a lambda-producing factory, and the host cell then lyses. 
B)  Most of the prophage genes are activated by the product of a particular prophage gene. 
C)  The phage genome is integrated in the host chromosome where it is replicated along with the host genome. 
D)  The phage DNA is copied and exits the cell as a phage. 
A)  After infection, the viral genes immediately turn the host cell into a lambda-producing factory, and the host cell then lyses. 
B)  Most of the prophage genes are activated by the product of a particular prophage gene. 
C)  The phage genome is integrated in the host chromosome where it is replicated along with the host genome. 
D)  The phage DNA is copied and exits the cell as a phage.

Question 14

Use the figure to answer the question.
 
In the figure, at the arrow marked II, what enzyme is being utilized?

Accepted Answer

A)  reverse transcriptase 
B)  viral DNA polymerase 
C)  host cell DNA polymerase 
D)  host cell RNA polymerase 
A)  reverse transcriptase 
B)  viral DNA polymerase 
C)  host cell DNA polymerase 
D)  host cell RNA polymerase

Question 15

To cause a human pandemic, the H5N1 avian flu virus would have to

Accepted Answer

A)  spread to primates such as chimpanzees. 
B)  develop into a virus with a different host range. 
C)  become capable of human-to-human transmission. 
D)  become much more pathogenic. 
A)  spread to primates such as chimpanzees. 
B)  develop into a virus with a different host range. 
C)  become capable of human-to-human transmission. 
D)  become much more pathogenic.

Question 16

Will treating a viral infection with antibiotics affect the course of the infection?

Accepted Answer

A)  No; antibiotics work by inhibiting enzymes specific to bacteria. Antibiotics have no effect on eukaryotic or virally encoded enzymes. 
B)  No; antibiotics do not kill viruses because viruses do not have DNA or RNA. 
C)  Yes; antibiotics activate the immune system, and this decreases the severity of the infection. 
D)  Yes; antibiotics can prevent viral entry into the cell by binding to host-receptor proteins. 
A)  No; antibiotics work by inhibiting enzymes specific to bacteria. Antibiotics have no effect on eukaryotic or virally encoded enzymes. 
B)  No; antibiotics do not kill viruses because viruses do not have DNA or RNA. 
C)  Yes; antibiotics activate the immune system, and this decreases the severity of the infection. 
D)  Yes; antibiotics can prevent viral entry into the cell by binding to host-receptor proteins.

Question 17

Use the figures to answer the question.
 
Which of the three types of viruses shown would you expect to include glycoproteins?

Accepted Answer

A)  I only 
B)  II only 
C)  III only 
D)  I and II only 
A)  I only 
B)  II only 
C)  III only 
D)  I and II only

Question 18

Refer to the treatments listed to answer the question.
You isolate an infectious substance capable of causing disease in plants, but you do not know whether the infectious agent is a bacterium, virus, or prion. You have four methods at your disposal to analyze the substance and determine the nature of the infectious agent.
I.Treat the substance with enzymes that destroy all nucleic acids, and then determine whether the substance is still infectious.
II.Filter the substance to remove all elements smaller than what can be easily seen under a light microscope.
III.Culture the substance on nutritive medium, away from any plant cells.
IV.Treat the sample with proteases that digest all proteins, and then determine whether the substance is still infectious.
If you already know that the infectious agent was either bacterial or viral, which method(s) listed above would allow you to distinguish between these two possibilities?

Accepted Answer

A)  I 
B)  II 
C)  II or III 
D)  IV 
A)  I 
B)  II 
C)  II or III 
D)  IV

Question 19

Which of the following human diseases is caused by a virus that requires reverse transcriptase to transcribe its genome inside the host cell?

Accepted Answer

A)  herpes 
B)  AIDS 
C)  smallpox 
D)  influenza 
A)  herpes 
B)  AIDS 
C)  smallpox 
D)  influenza

Question 20

A virus consisting of a single strand of RNA, which is reverse transcribed into complementary DNA, is referred to as a ________.

Accepted Answer

A)  protease 
B)  retrovirus 
C)  bacteriophage 
D)  non-enveloped virus 
A)  protease 
B)  retrovirus 
C)  bacteriophage 
D)  non-enveloped virus

Exam 19: Viruses

Which of the following processes within viral replication is the greatest source of genetic variation in RNA virus populations?

RNA viruses require their own supply of certain enzymes because

The difference between vertical and horizontal transmission of plant viruses is that vertical transmission is ________.

Why do RNA viruses appear to have higher rates of mutation?

A population of viruses with similar characteristics is called a ________.

Which of the following statements supports the argument that viruses are nonliving?

Which of the following statements is correct regarding viral infections in plants?

What is difference between an epidemic and a pandemic?

What are prions?

In many ways, the regulation of the genes of a particular group of viruses will be similar to the regulation of the host genes. Therefore, which of the following regulation mechanisms would you expect of the genes of a bacteriophage?

Which of the following statements accurately describes the lysogenic cycle of lambda (λ) phage?

Use the figure to answer the question. In the figure, at the arrow marked II, what enzyme is being utilized?

To cause a human pandemic, the H5N1 avian flu virus would have to

Will treating a viral infection with antibiotics affect the course of the infection?

Use the figures to answer the question. Which of the three types of viruses shown would you expect to include glycoproteins?

Which of the following human diseases is caused by a virus that requires reverse transcriptase to transcribe its genome inside the host cell?

A virus consisting of a single strand of RNA, which is reverse transcribed into complementary DNA, is referred to as a ________.

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

The Molecular Basis of Inheritance

Gene Expression: From Gene to Protein

Regulation of Gene Expression

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

Fungi

An Overview of Animal Diversity

An Introduction to Invertebrates

The Origin and Evolution of Vertebrates

Vascular Plant Structure, Growth, and Development

Resource Acquisition and Transport in Vascular Plants

Soil and Plant Nutrition

Angiosperm Reproduction and Biotechnology

Plant Responses to Internal and External Signals

Basic Principles of Animal Form and Function

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Osmoregulation and Excretion

Hormones and the Endocrine System

Animal Reproduction

Animal Development

Neurons, Synapses, and Signaling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behavior

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems and Restoration Ecology

Conservation Biology and Global Change

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