Question 1

Which of the following statements best 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. A

Question 2

Which of the following responses explain why the apparent high rate of mutation in RNA viruses?

Accepted Answer

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

Question 3

Use the figures to answer the question.   Which of the three types of viruses shown would you expect to have glycoproteins among its components?

Accepted Answer

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

Question 4

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

Accepted Answer

A)  In an animal, such as a pig, the influenza virus is mutated and replicated in alternate arrangements so that humans who eat the pig products can be infected. 
B)  An influenza virus from a human epidemic or pandemic infects birds; the birds replicate mutant versions of that virus and then pass the new forms back to humans. 
C)  An influenza virus fuses with a different type of virus (like HSV) and gains new DNA which enable the new virus to be transmitted to a wider variety of host species. 
D)  An animal, such as a pig, is infected with more than one strain of the influenza virus and the genomes reassort into new combinations that can facilitate spread to other species. 
A)  In an animal, such as a pig, the influenza virus is mutated and replicated in alternate arrangements so that humans who eat the pig products can be infected. 
B)  An influenza virus from a human epidemic or pandemic infects birds; the birds replicate mutant versions of that virus and then pass the new forms back to humans. 
C)  An influenza virus fuses with a different type of virus (like HSV) and gains new DNA which enable the new virus to be transmitted to a wider variety of host species. 
D)  An animal, such as a pig, is infected with more than one strain of the influenza virus and the genomes reassort into new combinations that can facilitate spread to other species.

Question 5

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 6

Use the figures to answer the question.   Which of the three types of viruses shown in the figure would you expect to include a capsid(s)?

Accepted Answer

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

Question 7

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 8

Use the following information to answer the question.
The herpes viruses are 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 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, and infect others.
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 ways to disinfect surfaces that came in contact with herpes simplex virus. 
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 ways to disinfect surfaces that came in contact with herpes simplex virus.

Question 9

Which of the following descriptions correctly identifies a main structural difference between viruses with envelopes and viruses without envelopes?

Accepted Answer

A)  Only viruses with envelopes have their contents enclosed by a layer containing lipids 
B)  Only viruses with envelopes package their genetic material by engulfing it. 
C)  Only viruses without envelopes can release their genetic material into the cytoplasm of the host. 
D)  Only viruses without envelopes interact with receptor proteins on the surface of the host cell. 
A)  Only viruses with envelopes have their contents enclosed by a layer containing lipids 
B)  Only viruses with envelopes package their genetic material by engulfing it. 
C)  Only viruses without envelopes can release their genetic material into the cytoplasm of the host. 
D)  Only viruses without envelopes interact with receptor proteins on the surface of the host cell.

Question 10

Which of the following statements correctly describes a characteristic of 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 11

Which of the following statements correctly describes vaccines and how they help prevent viral infection?

Accepted Answer

A)  Vaccines are active versions of a virus that stimulate an immune reaction in a person. 
B)  Vaccines are inactive versions of a virus that stimulate an immune reaction in a person. 
C)  Vaccines are infectious proteins that stimulate an immune reaction in a person. 
D)  Vaccines are functional pathogens that stimulate an immune reaction in a person. 
A)  Vaccines are active versions of a virus that stimulate an immune reaction in a person. 
B)  Vaccines are inactive versions of a virus that stimulate an immune reaction in a person. 
C)  Vaccines are infectious proteins that stimulate an immune reaction in a person. 
D)  Vaccines are functional pathogens that stimulate an immune reaction in a person.

Question 12

What is the function of reverse transcriptase in retroviruses?

Accepted Answer

A)  It uses viral RNA as a template for DNA synthesis. 
B)  It converts host cell RNA into viral DNA. 
C)  It translates viral RNA into proteins. 
D)  It uses viral RNA as a template for making more viral RNA strands. 
A)  It uses viral RNA as a template for DNA synthesis. 
B)  It converts host cell RNA into viral DNA. 
C)  It translates viral RNA into proteins. 
D)  It uses viral RNA as a template for making more viral RNA strands.

Question 13

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

Accepted Answer

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

Question 14

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)  RNA genomes are less stable than DNA genomes and the RNA breaks introduce mutations. 
D)  Viral RNA is translated by host cell ribosomes and viruses use slightly different codons. 
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)  RNA genomes are less stable than DNA genomes and the RNA breaks introduce mutations. 
D)  Viral RNA is translated by host cell ribosomes and viruses use slightly different codons.

Question 15

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

Question 16

Electron micrographs of herpes simplex virus (HSV) infection show the following progression; the intact virus first interacts with cell-surface proteoglycans and then with specific receptors, viral capsids dock with nuclear pores, and, finally, capsids go from being full to being "empty." Which of the following statements best fits these observations?

Accepted Answer

A)  Viral capsids are needed for the cell to become infected; its proteins mediate binding with specific cells. 
B)  The viral envelope is not required for infectivity; its components do not enter the nucleus. 
C)  Only the genetic material of the virus is involved in infection; it is injected into the cytoplasm like the genome of a phage. 
D)  The viral envelope mediates entry into the cell; the viral genome is all that enters the nucleus. 
A)  Viral capsids are needed for the cell to become infected; its proteins mediate binding with specific cells. 
B)  The viral envelope is not required for infectivity; its components do not enter the nucleus. 
C)  Only the genetic material of the virus is involved in infection; it is injected into the cytoplasm like the genome of a phage. 
D)  The viral envelope mediates entry into the cell; the viral genome is all that enters the nucleus.

Question 17

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 18

A few minutes of incubation at room temperature in the laboratory will inactivate HIV, but the flu virus is still active after incubating for several hours. What are the practical consequences of these findings?

Accepted Answer

A)  The flu virus is more sensitive to changes in temperature than HIV. 
B)  The flu virus can be transmitted more easily from person to person than HIV. 
C)  This property of HIV makes it more likely to be a pandemic than the flu virus. 
D)  Disinfecting surfaces will have more of an effect on reducing the spread of HIV than on reducing the spread of the flu. 
A)  The flu virus is more sensitive to changes in temperature than HIV. 
B)  The flu virus can be transmitted more easily from person to person than HIV. 
C)  This property of HIV makes it more likely to be a pandemic than the flu virus. 
D)  Disinfecting surfaces will have more of an effect on reducing the spread of HIV than on reducing the spread of the flu.

Question 19

Since viral gene expression is regulated by the same machinery as host cell gene expression, which of the following is most likely involved in regulating expression of bacteriophage genes?

Accepted Answer

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

Question 20

Which of the following characteristics correctly describes retroviruses?

Accepted Answer

A)  They are not destroyed or deactivated by heating. 
B)  They can only reproduce by infecting bacteria. 
C)  They have a single-stranded DNA that is integrated into the host cell genome. 
D)  They have a single-stranded RNA that acts as a template for DNA synthesis. 
A)  They are not destroyed or deactivated by heating. 
B)  They can only reproduce by infecting bacteria. 
C)  They have a single-stranded DNA that is integrated into the host cell genome. 
D)  They have a single-stranded RNA that acts as a template for DNA synthesis.

Exam 26: Introduction to Viruses

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

Which of the following responses explain why the apparent high rate of mutation in RNA viruses?

Use the figures to answer the question. Which of the three types of viruses shown would you expect to have glycoproteins among its components?

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

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

Use the figures to answer the question. Which of the three types of viruses shown in the figure would you expect to include a capsid(s)?

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

Which of the following descriptions correctly identifies a main structural difference between viruses with envelopes and viruses without envelopes?

Which of the following statements correctly describes a characteristic of viral infections in plants?

Which of the following statements correctly describes vaccines and how they help prevent viral infection?

What is the function of reverse transcriptase in retroviruses?

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

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

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

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

A few minutes of incubation at room temperature in the laboratory will inactivate HIV, but the flu virus is still active after incubating for several hours. What are the practical consequences of these findings?

Since viral gene expression is regulated by the same machinery as host cell gene expression, which of the following is most likely involved in regulating expression of bacteriophage genes?

Which of the following characteristics correctly describes retroviruses?

Biology and Its Themes

Atoms and Molecules

The Chemistry of Water

Carbon: the Basis of Molecular Diversity

Biological Macromolecules and Lipids

Energy and Life

Cell Structure and Function

Cell Membranes

Cellular Signaling

Cell Respiration

Photosynthetic Processes

Mitosis

Sexual Life Cycles and Meiosis

Mendelian Genetics

Linkage and Chromosomes

Nucleic Acids and Inheritance

Expression of Genes

Control of Gene Expression

Dna Technology

The Evolution of Genomes

How Evolution Works

Phylogenetic Reconstruction

Microevolution

Species and Speciation

Macroevolution

Prokaryotes

The Origin and Evolution of Eukaryotes

Nonvascular and Seedless Vascular Plants

Seed Plants

Introduction to Fungi

An Introduction to Animal Diversity

Invertebrates

Vertebrates

Plant Structure and Growth

Transport in Vascular Plants

Plant Nutrition

Reproduction of Flowering Plants

Plant Signals and Behavior

The Animal Body

Chemical Signals in Animals

Animal Digestive Systems

Animal Transport Systems

Animal Excretory Systems

Animal Reproductive Systems

Development in Animals

Animal Defenses Against Infection

Electrical Signals in Animals

Neural Regulation in Animals

Sensation and Movement in Animals

An Overview of Ecology

Behavioral Ecology

Populations and Life History Traits

Biodiversity and Communities

Energy Flow and Chemical Cycling in Ecosystems

Conservation and Global Ecology

Filters