Question 1

If a viral host cell has a mutation that interferes with the addition of carbohydrates to proteins in the Golgi,which of the following could likely result?

Accepted Answer

A) The viral envelope proteins will not be glycosylated and may not arrive at the host plasma membrane. 
B) The viral capsid proteins will not be glycosylated and may not arrive at the host plasma membrane. 
C) The viral core proteins will not be glycosylated and may not arrive at the host plasma membrane. 
D) None of the above will happen. 
A) The viral envelope proteins will not be glycosylated and may not arrive at the host plasma membrane. 
B) The viral capsid proteins will not be glycosylated and may not arrive at the host plasma membrane. 
C) The viral core proteins will not be glycosylated and may not arrive at the host plasma membrane. 
D) None of the above will happen. A

Question 2

You have been happily growing your bacterial cultures for many weeks.One day,you discover that one of your cultures has lysed.Which of the following experiments will indicate that a bacteriophage is responsible for the cell lysis?

Accepted Answer

A) You filter the lysed culture through a 0.3-micrometer filter and use the filtrate to infect more cells.After 45 minutes,the second bacterial culture lyses. 
B) You examine the lysed culture using the electron microscope and discover you have many particles about 50-nanometer long,with a head,tail,and tail spikes. 
C) You filter the lysed culture through a 0.3-micrometer filter and add fresh growth media.After 24 hours of incubation,the growth media is cloudy,like a bacterial culture. 
D) A and B. 
E) B and C. 
A) You filter the lysed culture through a 0.3-micrometer filter and use the filtrate to infect more cells.After 45 minutes,the second bacterial culture lyses. 
B) You examine the lysed culture using the electron microscope and discover you have many particles about 50-nanometer long,with a head,tail,and tail spikes. 
C) You filter the lysed culture through a 0.3-micrometer filter and add fresh growth media.After 24 hours of incubation,the growth media is cloudy,like a bacterial culture. 
D) A and B. 
E) B and C. D

Question 3

Viruses use the host's machinery to make copies of themselves.However,some human viruses require a type of replication that humans do not normally do.For example,humans normally do not have the ability to convert RNA into DNA.How can these types of viruses infect humans,when human cells cannot perform a particular role that the virus requires?

Accepted Answer

A) The virus causes mutations in the human cells,resulting in the formation of new enzymes that are capable of performing these roles. 
B) The virus has in its own genome the code for any specialized enzymes that the host does not have. 
C) The virus infects only those cells and species that can perform all the replication roles necessary. 
D) Viruses can stay in a quiescent state until the host cell evolves this ability. 
E) All of the above have been frequently observed. 
A) The virus causes mutations in the human cells,resulting in the formation of new enzymes that are capable of performing these roles. 
B) The virus has in its own genome the code for any specialized enzymes that the host does not have. 
C) The virus infects only those cells and species that can perform all the replication roles necessary. 
D) Viruses can stay in a quiescent state until the host cell evolves this ability. 
E) All of the above have been frequently observed. B

Question 4

The first class of drugs developed to treat AIDS-such as AZT-were known as reverse transcriptase inhibitors.What was the mechanism by which they worked to treat HIV infections?

Accepted Answer

A) They targeted and destroyed the viral genome before it could be reverse transcribed into DNA. 
B) They bonded to the dsDNA genome of the virus in such a way that it could not separate in order for replication to occur. 
C) They bonded to the viral reverse transcriptase enzyme,thus preventing the virus from making a DNA copy of its RNA genome. 
D) They prevented host cells from producing the enzymes used by the virus to replicate its genome. 
A) They targeted and destroyed the viral genome before it could be reverse transcribed into DNA. 
B) They bonded to the dsDNA genome of the virus in such a way that it could not separate in order for replication to occur. 
C) They bonded to the viral reverse transcriptase enzyme,thus preventing the virus from making a DNA copy of its RNA genome. 
D) They prevented host cells from producing the enzymes used by the virus to replicate its genome.

Question 5

When HIV infects people,it does not immediately induce AIDS and kill its host.When people die from HIV infections,it is usually because

Accepted Answer

A) they have too many HIV particles in their lymph system,which causes it to shut down. 
B) they have too few T cells and become susceptible to secondary infections and cancers. 
C) they have too many T cells,and this overwhelms their immune systems. 
D) the virus induces a coma and then eventually stops the heart muscle. 
E) the virus starts destroying cells as it divides and causes massive internal hemorrhaging that leads to shock and eventually death. 
A) they have too many HIV particles in their lymph system,which causes it to shut down. 
B) they have too few T cells and become susceptible to secondary infections and cancers. 
C) they have too many T cells,and this overwhelms their immune systems. 
D) the virus induces a coma and then eventually stops the heart muscle. 
E) the virus starts destroying cells as it divides and causes massive internal hemorrhaging that leads to shock and eventually death.

Question 6

In doing gene therapy,researchers frequently use attenuated viruses.The goal of gene therapy is to insert a normal copy of the mutated,disease-causing gene into the patient's genome,so that they will start producing normal protein.Which type of virus is suited to this application?

Accepted Answer

A) lytic viruses 
B) lysogenic viruses 
C) either lytic or lysogenic viruses 
A) lytic viruses 
B) lysogenic viruses 
C) either lytic or lysogenic viruses

Question 7

What is a significant difference between lytic and lysogenic viral growth?

Accepted Answer

A) In lytic growth,there are no mature viruses produced. 
B) In lysogenic growth,the viral genome gets incorporated into the host genome. 
C) In lytic growth,the host cells are not destroyed. 
D) In lysogenic growth,there is a continuous release of mature viral particles throughout the infection. 
A) In lytic growth,there are no mature viruses produced. 
B) In lysogenic growth,the viral genome gets incorporated into the host genome. 
C) In lytic growth,the host cells are not destroyed. 
D) In lysogenic growth,there is a continuous release of mature viral particles throughout the infection.

Question 8

Which of the following statements applies to the lysogenic cycle?

Accepted Answer

A) Viral proteins are used to replicate the viral genome. 
B) Viral particles are produced continuously. 
C) The viral genome integrates into the host cell's genome. 
D) When the cell divides,the daughter cells are no longer infected. 
A) Viral proteins are used to replicate the viral genome. 
B) Viral particles are produced continuously. 
C) The viral genome integrates into the host cell's genome. 
D) When the cell divides,the daughter cells are no longer infected.

Question 9

To make a vaccine against mumps,measles,or rabies,which type of viruses would be useful?

Accepted Answer

A) dsDNA viruses 
B) negative-sense ssRNA viruses 
C) retroviruses 
D) positive-sense ssRNA viruses 
E) dsRNA viruses 
A) dsDNA viruses 
B) negative-sense ssRNA viruses 
C) retroviruses 
D) positive-sense ssRNA viruses 
E) dsRNA viruses

Question 10

The European spruce sawflies pose a potential threat to spruce forests.Baculoviruses have proven to be highly effective biological control agents against these sawflies.Why would pest managers prefer to use a baculovirus rather than a predator feeding on the pest?

Accepted Answer

A) The baculovirus particles are harmless to vertebrates. 
B) Each type of baculovirus only kills a small number of host species. 
C) The virus cannot replicate outside of a host cell. 
D) All of the above are reasons a baculovirus would be preferred over a predator. 
A) The baculovirus particles are harmless to vertebrates. 
B) Each type of baculovirus only kills a small number of host species. 
C) The virus cannot replicate outside of a host cell. 
D) All of the above are reasons a baculovirus would be preferred over a predator.

Question 11

You have isolated the genome from a novel virus and would like to determine its composition.You have three tubes,each containing one of these substances: 1. a protein that degrades dsDNA (DNase,tube 1)
2) a protein that degrades ssRNA (RNase,tube 2)
3) a protease that degrades viral proteins (tube 3)
You add some of your novel genome to tubes 1,2,and 3.The genome is degraded in tube 2,but not in tube 1 or tube 3.Based on your knowledge of genome types that have been found in viruses,what could the genome's composition be?

Accepted Answer

A) dsDNA 
B) ssDNA 
C) ssRNA 
D) protein 
E) None of the above seem likely. 
A) dsDNA 
B) ssDNA 
C) ssRNA 
D) protein 
E) None of the above seem likely.

Question 12

The European spruce sawflies pose a potential threat to spruce forests.In order for the Baculoviruses to kill the larva,which of the following must occur first?

Accepted Answer

A) The viral polyhedra,must be digested to release viral particles. 
B) Viral polyhedra must fuse with intestinal cells. 
C) Viral particles must enter into the host's nucleus for transcription and replication. 
D) Viral particles must be digested by gut proteases. 
A) The viral polyhedra,must be digested to release viral particles. 
B) Viral polyhedra must fuse with intestinal cells. 
C) Viral particles must enter into the host's nucleus for transcription and replication. 
D) Viral particles must be digested by gut proteases.

Question 13

Which of the following is the most important reason that developing treatments and vaccines,as well as staging an effective immune response for HIV infections,has been so difficult compared with other viruses?

Accepted Answer

A) The virus evades the immune system and drugs by hiding inside cells of the immune system,such as helper T cells. 
B) The virus has few,if any,replication-correcting enzymes,and consequently mutates at a high rate. 
C) The virus has no recognizable antigens and,thus,cannot be identified easily by the host's immune system. 
D) Researchers probably have not yet identified the actual cause of AIDS and,thus,cannot target their drug development accordingly. 
A) The virus evades the immune system and drugs by hiding inside cells of the immune system,such as helper T cells. 
B) The virus has few,if any,replication-correcting enzymes,and consequently mutates at a high rate. 
C) The virus has no recognizable antigens and,thus,cannot be identified easily by the host's immune system. 
D) Researchers probably have not yet identified the actual cause of AIDS and,thus,cannot target their drug development accordingly.

Question 14

Which of the following is true regarding the ambi-sense virus?

Accepted Answer

A) The genome contains the same sequences as the mRNA required to produce viral proteins. 
B) The base sequences in the genome are complementary to those in viral mRNAs. 
C) Some sections of the genome are positive,while others are negative-sense. 
A) The genome contains the same sequences as the mRNA required to produce viral proteins. 
B) The base sequences in the genome are complementary to those in viral mRNAs. 
C) Some sections of the genome are positive,while others are negative-sense.

Question 15

Which of the following viruses would be the most likely to have reverse transcriptase?

Accepted Answer

A) an RNA-based lytic virus 
B) an RNA-based lysogenic virus 
C) a DNA-based lytic virus 
D) a DNA-based lysogenic virus 
A) an RNA-based lytic virus 
B) an RNA-based lysogenic virus 
C) a DNA-based lytic virus 
D) a DNA-based lysogenic virus

Question 16

You just discovered a new virus.This virus infects heart muscle,where it causes inflammation.This virus has a very high mutation rate.Which of the following is the best strategy for finding a treatment for this virus?

Accepted Answer

A) Develop a vaccine from living viruses. 
B) Identify the receptor this virus uses and develop an antibody against that receptor. 
C) Encourage infected individuals to engage in heart-strengthening exercise. 
D) Develop a drug that blocks the host's ribosomes,which the virus uses to produce its proteins. 
A) Develop a vaccine from living viruses. 
B) Identify the receptor this virus uses and develop an antibody against that receptor. 
C) Encourage infected individuals to engage in heart-strengthening exercise. 
D) Develop a drug that blocks the host's ribosomes,which the virus uses to produce its proteins.

Question 17

What is difference between an epidemic and a pandemic?

Accepted Answer

A) An epidemic is a disease that is restricted to a small area and does not appear to be spreading or becoming more common,whereas a pandemic is a disease that is spreading wider throughout a population. 
B) An epidemic is an actual disease,whereas a pandemic is a worldwide human response to treating that disease. 
C) An epidemic is a disease in a local region that is widening,whereas a pandemic is a disease that is widening to an international scale. 
D) An epidemic is a disease with a fairly low mortality rate,whereas a pandemic has a much higher mortality rate. 
A) An epidemic is a disease that is restricted to a small area and does not appear to be spreading or becoming more common,whereas a pandemic is a disease that is spreading wider throughout a population. 
B) An epidemic is an actual disease,whereas a pandemic is a worldwide human response to treating that disease. 
C) An epidemic is a disease in a local region that is widening,whereas a pandemic is a disease that is widening to an international scale. 
D) An epidemic is a disease with a fairly low mortality rate,whereas a pandemic has a much higher mortality rate.

Question 18

HIV is inactivated in the laboratory after a few minutes of sitting at room temperature;the flu virus is still active after sitting for several hours.What are the practical consequences of these findings?

Accepted Answer

A) HIV can be transmitted from person to person by sexual contact or injection of infected blood products. 
B) The flu virus can be transmitted from person to person by contact with a contaminated surface. 
C) The flu virus can be transmitted from person to person by direct physical contact. 
D) Both A and B apply. 
E) All of the above answers apply. 
A) HIV can be transmitted from person to person by sexual contact or injection of infected blood products. 
B) The flu virus can be transmitted from person to person by contact with a contaminated surface. 
C) The flu virus can be transmitted from person to person by direct physical contact. 
D) Both A and B apply. 
E) All of the above answers apply.

Question 19

Which of the following plays an important role in the ability of an enveloped virus to fuse with the host cell?

Accepted Answer

A) Presence of antibodies on the host cell surface that recognize the virus. 
B) Presence of the same phospholipid bilayer structure in both virus and host cell. 
C) Presence of capsid protein shell on the outermost layer of the virus. 
D) Answers A and B 
A) Presence of antibodies on the host cell surface that recognize the virus. 
B) Presence of the same phospholipid bilayer structure in both virus and host cell. 
C) Presence of capsid protein shell on the outermost layer of the virus. 
D) Answers A and B

Question 20

To make a vaccine against the polio virus,researchers treated the polio virus with formaldehyde and used this preparation to inject people.This is an example of

Accepted Answer

A) an inactivated virus vaccine. 
B) an attenuated virus vaccine. 
C) a vaccine of isolated viral proteins. 
A) an inactivated virus vaccine. 
B) an attenuated virus vaccine. 
C) a vaccine of isolated viral proteins.

Exam 35: Viruses

If a viral host cell has a mutation that interferes with the addition of carbohydrates to proteins in the Golgi,which of the following could likely result?

You have been happily growing your bacterial cultures for many weeks.One day,you discover that one of your cultures has lysed.Which of the following experiments will indicate that a bacteriophage is responsible for the cell lysis?

The first class of drugs developed to treat AIDS-such as AZT-were known as reverse transcriptase inhibitors.What was the mechanism by which they worked to treat HIV infections?

When HIV infects people,it does not immediately induce AIDS and kill its host.When people die from HIV infections,it is usually because

In doing gene therapy,researchers frequently use attenuated viruses.The goal of gene therapy is to insert a normal copy of the mutated,disease-causing gene into the patient's genome,so that they will start producing normal protein.Which type of virus is suited to this application?

What is a significant difference between lytic and lysogenic viral growth?

Which of the following statements applies to the lysogenic cycle?

To make a vaccine against mumps,measles,or rabies,which type of viruses would be useful?

The European spruce sawflies pose a potential threat to spruce forests.Baculoviruses have proven to be highly effective biological control agents against these sawflies.Why would pest managers prefer to use a baculovirus rather than a predator feeding on the pest?

The European spruce sawflies pose a potential threat to spruce forests.In order for the Baculoviruses to kill the larva,which of the following must occur first?

Which of the following is the most important reason that developing treatments and vaccines,as well as staging an effective immune response for HIV infections,has been so difficult compared with other viruses?

Which of the following is true regarding the ambi-sense virus?

Which of the following viruses would be the most likely to have reverse transcriptase?

You just discovered a new virus.This virus infects heart muscle,where it causes inflammation.This virus has a very high mutation rate.Which of the following is the best strategy for finding a treatment for this virus?

What is difference between an epidemic and a pandemic?

HIV is inactivated in the laboratory after a few minutes of sitting at room temperature;the flu virus is still active after sitting for several hours.What are the practical consequences of these findings?

Which of the following plays an important role in the ability of an enveloped virus to fuse with the host cell?

To make a vaccine against the polio virus,researchers treated the polio virus with formaldehyde and used this preparation to inject people.This is an example of

Biology and the Tree of Life

Water and Carbon: the Chemical Basis of Life

Protein Structure and Function

Nucleic Acids and the Rna World

An Introduction to Carbohydrates

Lipids, membranes, and the First Cells

Inside the Cell

Cell-Cell Interactions

Cellular Respiration and Fermentation

Photosynthesis

The Cell Cycle

Meiosis

Mendel and the Gene

Dna and the Gene: Synthesis and Repair

How Genes Work

Transcription, RNA Processing, and Translation

Control of Gene Expression in Bacteria

Control of Gene Expression in Eukaryotes

Analyzing and Engineering Genes

Genomics

Principles of Development

An Introduction to Animal Development

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Evolution by Natural Selection

Evolutionary Processes

Speciation

Phylogenies and the History of Life

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Protists

Green Algae and Land Plants

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An Introduction to Animals

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Water and Sugar Transport in Plants

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Plant Sensory Systems, signals, and Responses

Plant Reproduction

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Water and Electrolyte Balance in Animals

Animal Nutrition

Gas Exchange and Circulation

Electrical Signals in Animals

Animal Sensory Systems and Movement

Chemical Signals in Animals

Animal Reproduction

The Immune System in Animals

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