Question 1

Plant viruses may be transmitted by

Accepted Answer

A)  worms. 
B)  contaminated seeds. 
C)  humans. 
D)  insects. 
E)  All of the choices are correct. 
A)  worms. 
B)  contaminated seeds. 
C)  humans. 
D)  insects. 
E)  All of the choices are correct.

Question 2

The best known chronic infection involves

Accepted Answer

A)  hepatitis B. 
B)  hepatitis A. 
C)  chickenpox. 
D)  herpes. 
E)  influenza. 
A)  hepatitis B. 
B)  hepatitis A. 
C)  chickenpox. 
D)  herpes. 
E)  influenza.

Question 3

Your boyfriend wonders whether hepatitis B is really a problematic disease. He says that the job of your immune system is to get rid of viruses and virus-infected cells. You tell him that hepatitis B causes an infection in which the causative agent remains in the body for years or even a lifetime, often without causing symptoms of disease. This type of infection is characterized by the continuous low-level production of viral particles and is called a(n) ________ infection.

Accepted Answer

A)  persistent only 
B)  persistent AND latent 
C)  chronic only 
D)  latent only 
E)  persistent AND chronic 
A)  persistent only 
B)  persistent AND latent 
C)  chronic only 
D)  latent only 
E)  persistent AND chronic

Question 4

The term "segmented" refers to viruses that

Accepted Answer

A)  may contain several pieces of RNA. 
B)  have an icosahedral-shaped capsid. 
C)  are linked together before budding out. 
D)  have an envelope that has several components. 
E)  may contain RNA with undefined regions in it. 
A)  may contain several pieces of RNA. 
B)  have an icosahedral-shaped capsid. 
C)  are linked together before budding out. 
D)  have an envelope that has several components. 
E)  may contain RNA with undefined regions in it.

Question 5

Your boyfriend asks how animal viruses enter a host cell. You tell him that they can use one of two mechanisms:

Accepted Answer

A)  exocytosis OR fusion 
B)  endocytosis OR fusion 
C)  fusion OR phagocytosis 
D)  endocytosis OR budding 
E)  budding OR fusion 
A)  exocytosis OR fusion 
B)  endocytosis OR fusion 
C)  fusion OR phagocytosis 
D)  endocytosis OR budding 
E)  budding OR fusion

Question 6

Prions are

Accepted Answer

A)  a form of RNA virus. 
B)  a form of DNA virus. 
C)  a viroid. 
D)  an infectious protein. 
E)  an infected protein. 
A)  a form of RNA virus. 
B)  a form of DNA virus. 
C)  a viroid. 
D)  an infectious protein. 
E)  an infected protein.

Question 7

Cells infected with animal viruses lyse because

Accepted Answer

A)  the release of the virions depletes the cell of energy. 
B)  the virus releases enzymes that lyse the cell. 
C)  functions necessary for cell survival are not carried out and the cell dies. 
D)  the virus RNA and cellular protein interact to kill the cell. 
E)  the viruses release lysozyme which destroys the host cell wall. 
A)  the release of the virions depletes the cell of energy. 
B)  the virus releases enzymes that lyse the cell. 
C)  functions necessary for cell survival are not carried out and the cell dies. 
D)  the virus RNA and cellular protein interact to kill the cell. 
E)  the viruses release lysozyme which destroys the host cell wall.

Question 8

In the region of budding, the inside of the cytoplasmic membrane becomes coated with

Accepted Answer

A)  enzymes. 
B)  carbohydrates. 
C)  steroids. 
D)  matrix proteins. 
E)  phospholipids. 
A)  enzymes. 
B)  carbohydrates. 
C)  steroids. 
D)  matrix proteins. 
E)  phospholipids.

Question 9

Viruses that infect bacteria are referred to as

Accepted Answer

A)  viralcidens. 
B)  bacteriocidins. 
C)  bacterialogens. 
D)  bacteriophages. 
E)  virophages. 
A)  viralcidens. 
B)  bacteriocidins. 
C)  bacterialogens. 
D)  bacteriophages. 
E)  virophages.

Question 10

The changes that occur in virally infected cells are characteristic for a particular virus and are referred to as the

Accepted Answer

A)  cytopathic effect. 
B)  phenotypic effect. 
C)  genotypic expression. 
D)  cytology. 
E)  symptomatic effect. 
A)  cytopathic effect. 
B)  phenotypic effect. 
C)  genotypic expression. 
D)  cytology. 
E)  symptomatic effect.

Question 11

Bacteriophages, unlike animal viruses, often have special viral-specific enzymes carried in the capsid, which enter the host cell at the same time as the nucleic acid.

Accepted Answer

A) True 
 B)False

Question 12

In the replication of phage containing positive-sense DNA,

Accepted Answer

A)  the host's enzymes are used to make dsDNA. 
B)  the host's DNA polymerase uses the phage RNA as a template to make negative-sense DNA. 
C)  a phage-encoded DNA polymerase is used to make negative-sense RNA using the phage positive-sense RNA as a template. 
D)  a phage-encoded DNA polymerase is used to make DNA using the phage positive-sense RNA as a template. 
E)  a phage-encoded RNA polymerase is used to make DNA using the phage positive-sense RNA as a template. 
A)  the host's enzymes are used to make dsDNA. 
B)  the host's DNA polymerase uses the phage RNA as a template to make negative-sense DNA. 
C)  a phage-encoded DNA polymerase is used to make negative-sense RNA using the phage positive-sense RNA as a template. 
D)  a phage-encoded DNA polymerase is used to make DNA using the phage positive-sense RNA as a template. 
E)  a phage-encoded RNA polymerase is used to make DNA using the phage positive-sense RNA as a template.

Question 13

Non-enveloped and enveloped viruses both may enter the host via endocytosis.

Accepted Answer

A) True 
 B)False

Question 14

Spongiform encephalopathy occurs in all of the following EXCEPT

Accepted Answer

A)  plants. 
B)  humans. 
C)  cattle. 
D)  sheep. 
E)  cattle AND sheep. 
A)  plants. 
B)  humans. 
C)  cattle. 
D)  sheep. 
E)  cattle AND sheep.

Question 15

The integration of phage DNA into host DNA occurs in much the same fashion as seen in transformation, transduction, or conjugation.

Accepted Answer

A) True 
 B)False

Question 16

Electron microscopy is useful for counting viruses and distinguishing between infective and non-infective virions.

Accepted Answer

A) True 
 B)False

Question 17

There are ________ major families of DNA-containing viruses that infect vertebrates.

Accepted Answer

A)  7 
B)  5 
C)  4 
D)  2 
E)  6 
A)  7 
B)  5 
C)  4 
D)  2 
E)  6

Question 18

Transducing virulent phages do not lyse the cells they invade because

Accepted Answer

A)  transformation is taking place in the phage and this is transferred to the bacterium. 
B)  bacterial DNA has replaced critical viral DNA in the phage. 
C)  their virulence is dependent on the bacteria and virus replicating together. 
D)  the lytic genes are unable to enter during penetration and are shed outside the host. 
E)  viral DNA has replaced critical bacterial DNA in the phage. 
A)  transformation is taking place in the phage and this is transferred to the bacterium. 
B)  bacterial DNA has replaced critical viral DNA in the phage. 
C)  their virulence is dependent on the bacteria and virus replicating together. 
D)  the lytic genes are unable to enter during penetration and are shed outside the host. 
E)  viral DNA has replaced critical bacterial DNA in the phage.

Question 19

The structure of plant, animal, and bacterial viruses are each, fundamentally, very different from one another.

Accepted Answer

A) True 
 B)False

Question 20

Explain why HIV becomes resistant so quickly when a single drug is used therapeutically.

Accepted Answer

A)  The virus is an RNA genome virus. By using host RNA polymerase to directly copy the genome to make more virus particles, there's no proofreading capability. This leads to a high rate of mutation of the viral genome and increased chance for drug resistance. 
B)  HIV uses reverse transcriptase to make a cDNA version of its RNA genome. This polymerase is "'sloppy," with a high rate of error and lack of a proofreading capability. This leads to a high rate of mutation of the viral genome and increased chance for drug resistance. 
C)  HIV synthesizes a protein enzyme that directly cleaves anti-HIV drugs, giving it a characteristically high rate of resistance to a single drug type. 
D)  HIV is constantly changing its genetic structure by swapping genetic elements with other virus strains. This leads to a high rate of mutation of the viral genome and increased chance for drug resistance. 
E)  Like bacteria, HIV undergoes spontaneous mutation in the presence of antibiotics, so multiple medications are used simultaneously to reduce the chance of this happening. 
A)  The virus is an RNA genome virus. By using host RNA polymerase to directly copy the genome to make more virus particles, there's no proofreading capability. This leads to a high rate of mutation of the viral genome and increased chance for drug resistance. 
B)  HIV uses reverse transcriptase to make a cDNA version of its RNA genome. This polymerase is "'sloppy," with a high rate of error and lack of a proofreading capability. This leads to a high rate of mutation of the viral genome and increased chance for drug resistance. 
C)  HIV synthesizes a protein enzyme that directly cleaves anti-HIV drugs, giving it a characteristically high rate of resistance to a single drug type. 
D)  HIV is constantly changing its genetic structure by swapping genetic elements with other virus strains. This leads to a high rate of mutation of the viral genome and increased chance for drug resistance. 
E)  Like bacteria, HIV undergoes spontaneous mutation in the presence of antibiotics, so multiple medications are used simultaneously to reduce the chance of this happening.

Exam 13: Viruses, Viroids, and Prions

Plant viruses may be transmitted by

The best known chronic infection involves

The term "segmented" refers to viruses that

Your boyfriend asks how animal viruses enter a host cell. You tell him that they can use one of two mechanisms:

Prions are

Cells infected with animal viruses lyse because

In the region of budding, the inside of the cytoplasmic membrane becomes coated with

Viruses that infect bacteria are referred to as

The changes that occur in virally infected cells are characteristic for a particular virus and are referred to as the

Bacteriophages, unlike animal viruses, often have special viral-specific enzymes carried in the capsid, which enter the host cell at the same time as the nucleic acid.

In the replication of phage containing positive-sense DNA,

Non-enveloped and enveloped viruses both may enter the host via endocytosis.

Spongiform encephalopathy occurs in all of the following EXCEPT

The integration of phage DNA into host DNA occurs in much the same fashion as seen in transformation, transduction, or conjugation.

Electron microscopy is useful for counting viruses and distinguishing between infective and non-infective virions.

There are ________ major families of DNA-containing viruses that infect vertebrates.

Transducing virulent phages do not lyse the cells they invade because

The structure of plant, animal, and bacterial viruses are each, fundamentally, very different from one another.

Explain why HIV becomes resistant so quickly when a single drug is used therapeutically.

Humans and the Microbial World

The Molecules of Life

Microscopy and Cell Structure

Dynamics of Microbial Growth

Control of Microbial Growth

Microbial Metabolism: Fueling Cell Growth

The Blueprint of Life, From Dna to Protein

Bacterial Genetics

Biotechnology

Identifying and Classifying Microorganisms

The Diversity of Bacteria and Archaea

The Eukaryotic Members of the Microbial World

The Innate Immune Response

The Adaptive Immune Response

Host-Microbe Interactions

Immunological Disorders

Applications of Immune Responses

Epidemiology

Antimicrobial Medications

Respiratory System Infections

Skin Infections

Wound Infections

Digestive System Infections

Blood and Lymphatic Infections

Nervous System Infections

Genitourinary Tract Infections

Microbial Ecology

Environmental Microbiology: Treatment of Water, Wastes, and Polluted Habitats

Food Microbiology

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