Question 1

Which of the following accounts for someone who has had a herpesvirus-mediated cold sore or genital sore getting flare-ups for the rest of his or her life?

Accepted Answer

A)  re-infection by a closely related herpesvirus of a different strain 
B)  re-infection by the same herpesvirus strain 
C)  co-infection with an unrelated virus that causes the same symptoms 
D)  copies of the herpesvirus genome permanently maintained in host nuclei 
E)  copies of the herpesvirus genome permanently maintained in host cell cytoplasm 
A)  re-infection by a closely related herpesvirus of a different strain 
B)  re-infection by the same herpesvirus strain 
C)  co-infection with an unrelated virus that causes the same symptoms 
D)  copies of the herpesvirus genome permanently maintained in host nuclei 
E)  copies of the herpesvirus genome permanently maintained in host cell cytoplasm D

Question 2

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. Which of the following would be expected to occur?

Accepted Answer

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

Question 3

What is the function of reverse transcriptase in retroviruses?

Accepted Answer

A)  It hydrolyzes the host cell's DNA. 
B)  It uses viral RNA as a template for DNA synthesis. 
C)  It converts host cell RNA into viral DNA. 
D)  It translates viral RNA into proteins. 
E)  It uses viral RNA as a template for making complementary RNA strands. 
A)  It hydrolyzes the host cell's DNA. 
B)  It uses viral RNA as a template for DNA synthesis. 
C)  It converts host cell RNA into viral DNA. 
D)  It translates viral RNA into proteins. 
E)  It uses viral RNA as a template for making complementary RNA strands. B

Question 4

Which of the following is characteristic of the lytic cycle?

Accepted Answer

A)  Many bacterial cells containing viral DNA are produced. 
B)  Viral DNA is incorporated into the host genome. 
C)  The viral genome replicates without destroying the host. 
D)  A large number of phages are released at a time. 
E)  The virus-host relationship usually lasts for generations. 
A)  Many bacterial cells containing viral DNA are produced. 
B)  Viral DNA is incorporated into the host genome. 
C)  The viral genome replicates without destroying the host. 
D)  A large number of phages are released at a time. 
E)  The virus-host relationship usually lasts for generations.

Question 5

Antiviral drugs that have become useful are usually associated with which of the following properties?

Accepted Answer

A)  ability to remove all viruses from the infected host 
B)  interference with viral replication 
C)  prevention of the host from becoming infected 
D)  removal of viral proteins 
E)  removal of viral mRNAs 
A)  ability to remove all viruses from the infected host 
B)  interference with viral replication 
C)  prevention of the host from becoming infected 
D)  removal of viral proteins 
E)  removal of viral mRNAs

Question 6

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 would you expect of the genes of the 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 
E)  utilization of eukaryotic polymerases 
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 
E)  utilization of eukaryotic polymerases

Question 7

Use the following information to answer the few questions.
The herpesviruses are very important enveloped DNA viruses that cause disease in all vertebrate species and in some invertebrates such as oysters. Some of the human ones 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 then reactivate, replicate again, and be infectious to others.
-In order to be able to remain latent in an infected live cell, HSV must be able to shut down what process?

Accepted Answer

A)  DNA replication 
B)  transcription of viral genes 
C)  apoptosis of a virally infected cell 
D)  all immune responses 
E)  interaction with histones 
A)  DNA replication 
B)  transcription of viral genes 
C)  apoptosis of a virally infected cell 
D)  all immune responses 
E)  interaction with histones

Question 8

Which of the following can be effective in preventing the onset of viral infection in humans?

Accepted Answer

A)  taking vitamins 
B)  getting vaccinated 
C)  taking antibiotics 
D)  applying antiseptics 
E)  taking nucleoside analogs that inhibit transcription 
A)  taking vitamins 
B)  getting vaccinated 
C)  taking antibiotics 
D)  applying antiseptics 
E)  taking nucleoside analogs that inhibit transcription

Question 9

Use the following information to answer the following questions.
In 1971, David Baltimore described a scheme for classifying viruses based on how the virus produces mRNA.
Table 17.1 shows the results of testing five viruses (A-E) for nuclease specificity, the ability of the viral genome to act as an mRNA, and the presence (+) or absence (-) of each virus's own polymerase.   Table 17.1
-Based on Table 17.1, which virus meets the requirements for a bacteriophage?

Accepted Answer

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

Question 10

Emerging viruses arise by

Accepted Answer

A)  mutation of existing viruses. 
B)  the spread of existing viruses to new host species. 
C)  the spread of existing viruses more widely within their host species. 
D)  all of the above 
E)  none of the above 
A)  mutation of existing viruses. 
B)  the spread of existing viruses to new host species. 
C)  the spread of existing viruses more widely within their host species. 
D)  all of the above 
E)  none of the above

Question 11

Refer to the treatments listed below to answer the following questions.
You isolate an infectious substance that is capable of causing disease in plants, but you do not know whether the infectious agent is a bacterium, virus, viroid, or prion. You have four methods at your disposal that you can use to analyze the substance in order to determine the nature of the infectious agent.
I. treating the substance with nucleases that destroy all nucleic acids
and then determining whether it is still infectious
II. filtering the substance to remove all elements smaller than what can
be easily seen under a light microscope
III. culturing the substance by itself on nutritive medium, away from
any plant cells
IV. treating the sample with proteases that digest all proteins and then
determining whether it is still infectious
-If you already knew that the infectious agent was either bacterial or viral, which treatment would allow you to distinguish between these two possibilities?

Accepted Answer

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

Question 12

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. 
E)  these enzymes cannot be made in host cells. 
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. 
E)  these enzymes cannot be made in host cells.

Question 13

The host range of a virus is determined by

Accepted Answer

A)  the enzymes carried by the virus. 
B)  whether its nucleic acid is DNA or RNA. 
C)  the proteins in the host's cytoplasm. 
D)  the enzymes produced by the virus before it infects the cell. 
E)  the proteins on its surface and that of the host. 
A)  the enzymes carried by the virus. 
B)  whether its nucleic acid is DNA or RNA. 
C)  the proteins in the host's cytoplasm. 
D)  the enzymes produced by the virus before it infects the cell. 
E)  the proteins on its surface and that of the host.

Question 14

Which of the following is the most probable fate of a newly emerging virus that causes high mortality in its host?

Accepted Answer

A)  It is able to spread to a large number of new hosts quickly because the new hosts have no immunological memory of them. 
B)  The new virus replicates quickly and undergoes rapid adaptation to a series of divergent hosts. 
C)  A change in environmental conditions such as weather patterns quickly forces the new virus to invade new areas. 
D)  Sporadic outbreaks will be followed almost immediately by a widespread pandemic. 
E)  The newly emerging virus will die out rather quickly or will mutate to be far less lethal. 
A)  It is able to spread to a large number of new hosts quickly because the new hosts have no immunological memory of them. 
B)  The new virus replicates quickly and undergoes rapid adaptation to a series of divergent hosts. 
C)  A change in environmental conditions such as weather patterns quickly forces the new virus to invade new areas. 
D)  Sporadic outbreaks will be followed almost immediately by a widespread pandemic. 
E)  The newly emerging virus will die out rather quickly or will mutate to be far less lethal.

Question 15

Figure 17.1
-Which of the three types of viruses shown in Figure 17.1 would you expect to include a capsid(s)?

Accepted Answer

A)  I only 
B)  II only 
C)  III only 
D)  I and II only 
E)  all three 
A)  I only 
B)  II only 
C)  III only 
D)  I and II only 
E)  all three

Question 16

A bacterium is infected with an experimentally constructed bacteriophage composed of the T2 phage protein coat and T4 phage DNA. The new phages produced will have

Accepted Answer

A)  T2 protein and T4 DNA. 
B)  T2 protein and T2 DNA. 
C)  a mixture of the DNA and proteins of both phages. 
D)  T4 protein and T4 DNA. 
E)  T4 protein and T2 DNA. 
A)  T2 protein and T4 DNA. 
B)  T2 protein and T2 DNA. 
C)  a mixture of the DNA and proteins of both phages. 
D)  T4 protein and T4 DNA. 
E)  T4 protein and T2 DNA.

Question 17

A human pandemic is

Accepted Answer

A)  a viral disease that infects all humans. 
B)  a flu that kills more than 1 million people. 
C)  an epidemic that extends around the world. 
D)  a viral disease that can infect multiple species. 
E)  a virus that increases in mortality rate as it spreads. 
A)  a viral disease that infects all humans. 
B)  a flu that kills more than 1 million people. 
C)  an epidemic that extends around the world. 
D)  a viral disease that can infect multiple species. 
E)  a virus that increases in mortality rate as it spreads.

Question 18

Use the following information to answer the following questions.
In 1971, David Baltimore described a scheme for classifying viruses based on how the virus produces mRNA.
Table 17.1 shows the results of testing five viruses (A-E) for nuclease specificity, the ability of the viral genome to act as an mRNA, and the presence (+) or absence (-) of each virus's own polymerase.   Table 17.1
-Based on Table 17.1, which virus meets the Baltimore requirements for a retrovirus?

Accepted Answer

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

Question 19

Which of the following series best reflects what we know about how the flu virus moves between species?

Accepted Answer

A)  An avian flu virus undergoes several mutations and rearrangements such that it is able to be transmitted to other birds and then to humans. 
B)  The flu virus in a pig is mutated and replicated in alternate arrangements so that humans who eat the pig products can be infected. 
C)  A flu virus from a human epidemic or pandemic infects birds; the birds replicate the virus differently and then pass it back to humans. 
D)  An influenza virus gains new sequences of DNA from another virus, such as a herpesvirus; this enables it to be transmitted to a human host. 
E)  An animal such as a pig is infected with more than one virus, genetic recombination occurs, the new virus mutates and is passed to a new species such as a bird, and the virus mutates and can be transmitted to humans. 
A)  An avian flu virus undergoes several mutations and rearrangements such that it is able to be transmitted to other birds and then to humans. 
B)  The flu virus in a pig is mutated and replicated in alternate arrangements so that humans who eat the pig products can be infected. 
C)  A flu virus from a human epidemic or pandemic infects birds; the birds replicate the virus differently and then pass it back to humans. 
D)  An influenza virus gains new sequences of DNA from another virus, such as a herpesvirus; this enables it to be transmitted to a human host. 
E)  An animal such as a pig is infected with more than one virus, genetic recombination occurs, the new virus mutates and is passed to a new species such as a bird, and the virus mutates and can be transmitted to humans.

Question 20

Which of the following characteristics, structures, or processes is common to both bacteria and viruses?

Accepted Answer

A)  metabolism 
B)  ribosomes 
C)  genetic material composed of nucleic acid 
D)  cell division 
E)  independent existence 
A)  metabolism 
B)  ribosomes 
C)  genetic material composed of nucleic acid 
D)  cell division 
E)  independent existence

Exam 17: Viruses

Which of the following accounts for someone who has had a herpesvirus-mediated cold sore or genital sore getting flare-ups for the rest of his or her life?

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. Which of the following would be expected to occur?

What is the function of reverse transcriptase in retroviruses?

Which of the following is characteristic of the lytic cycle?

Antiviral drugs that have become useful are usually associated with which of the following properties?

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 would you expect of the genes of the bacteriophage?

Which of the following can be effective in preventing the onset of viral infection in humans?

Emerging viruses arise by

RNA viruses require their own supply of certain enzymes because

The host range of a virus is determined by

Which of the following is the most probable fate of a newly emerging virus that causes high mortality in its host?

Figure 17.1 -Which of the three types of viruses shown in Figure 17.1 would you expect to include a capsid(s)?

A bacterium is infected with an experimentally constructed bacteriophage composed of the T2 phage protein coat and T4 phage DNA. The new phages produced will have

A human pandemic is

Which of the following series best reflects what we know about how the flu virus moves between species?

Which of the following characteristics, structures, or processes is common to both bacteria and viruses?

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

The Molecular Basis of Inheritance

Gene Expression: From Gene to Protein

Regulation of Gene Expression

Development, Stem Cells, and Cancer

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

Species Interactions

Ecosystems and Energy

Global Ecology and Conservation Biology

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