Question 1

Which of the following is NOT True of prions?

Accepted Answer

A)  Prions replicate by converting normal host prion proteins into abnormal prion proteins. 
B)  Prions responsible for "mad cow disease" can cause a similar disease in humans. 
C)  Prions can be transmitted by consumption of dried food or cooked food. 
D)  Prions that cause spongiform encephalopathies have a different amino acid sequence from PrPᶜ. 
E)  All of the answer choices are correct. 
A)  Prions replicate by converting normal host prion proteins into abnormal prion proteins. 
B)  Prions responsible for "mad cow disease" can cause a similar disease in humans. 
C)  Prions can be transmitted by consumption of dried food or cooked food. 
D)  Prions that cause spongiform encephalopathies have a different amino acid sequence from PrPᶜ. 
E)  All of the answer choices are correct.

Question 2

You add an unknown phage to a mixture of F⁺ and F− cells of E. coli and plate out the bacteria. The bacterial colonies that grow are all F−. How can you explain this phenomenon?

Accepted Answer

A)  The phage bound to a receptor on the sex pilus, and therefore only infected the F⁺ cells (leaving the F− cells alone). 
B)  The phage bound to a receptor on the F− cells, leaving only them alive and allowing the F⁺ cells to die off. 
C)  The phage integrated (lysogenized) the F− cells, giving them a selective advantage over the F⁺ cells. 
D)  F⁺ cells are uniquely susceptible to phage attack for unknown reasons. 
E)  F⁺ are well known to die in the presence of any type of bacteriophage. 
A)  The phage bound to a receptor on the sex pilus, and therefore only infected the F⁺ cells (leaving the F− cells alone). 
B)  The phage bound to a receptor on the F− cells, leaving only them alive and allowing the F⁺ cells to die off. 
C)  The phage integrated (lysogenized) the F− cells, giving them a selective advantage over the F⁺ cells. 
D)  F⁺ cells are uniquely susceptible to phage attack for unknown reasons. 
E)  F⁺ are well known to die in the presence of any type of bacteriophage.

Question 3

The time from absorption to release for T-even phage is about

Accepted Answer

A)  1 day. 
B)  30 minutes. 
C)  10 minutes. 
D)  1 minute. 
E)  45 seconds. 
A)  1 day. 
B)  30 minutes. 
C)  10 minutes. 
D)  1 minute. 
E)  45 seconds.

Question 4

Plant viruses enter the host plant via

Accepted Answer

A)  wound sites. 
B)  specific receptors. 
C)  nonspecific receptors. 
D)  seeds. 
E)  endocytosis. 
A)  wound sites. 
B)  specific receptors. 
C)  nonspecific receptors. 
D)  seeds. 
E)  endocytosis.

Question 5

During penetration of E. coli by the T4 phage,

Accepted Answer

A)  lysozyme is used to allow entry of the phage capsid. 
B)  the tail acts as a "hypodermic needle," injecting the phage DNA into the cell. 
C)  the protein fibers digest a hole in the cell wall. 
D)  the bacterial receptor molecules open a hole through the cell wall. 
E)  the intact phage enters the host by endocytosis. 
A)  lysozyme is used to allow entry of the phage capsid. 
B)  the tail acts as a "hypodermic needle," injecting the phage DNA into the cell. 
C)  the protein fibers digest a hole in the cell wall. 
D)  the bacterial receptor molecules open a hole through the cell wall. 
E)  the intact phage enters the host by endocytosis.

Question 6

The best-known examples of viruses that cause latent infections are

Accepted Answer

A)  polio AND herpes. 
B)  herpes AND measles. 
C)  measles AND chickenpox. 
D)  chickenpox AND polio. 
E)  herpes AND chickenpox. 
A)  polio AND herpes. 
B)  herpes AND measles. 
C)  measles AND chickenpox. 
D)  chickenpox AND polio. 
E)  herpes AND chickenpox.

Question 7

Would you expect the number of virions to be the same if you measured them by the plaque assay or by counting using the electron microscope? Why?

Accepted Answer

A)  Yes-both methods measure the total number of virus particles in a solution. 
B)  No-the plaque assay only measures viable virus particles, while the electron microscope cannot distinguish between defective and viable virus. 
C)  No-you cannot count virus particles by using a plaque assay. You can only get a relative difference in quantity from one preparation of virus particles to another with this method. 
D)  Yes-only fully functioning viruses will be released from a host cell, so the quantified number of virus particles in a plaque assay should be identical to the number of free virus particles counted by electron microscopy. 
A)  Yes-both methods measure the total number of virus particles in a solution. 
B)  No-the plaque assay only measures viable virus particles, while the electron microscope cannot distinguish between defective and viable virus. 
C)  No-you cannot count virus particles by using a plaque assay. You can only get a relative difference in quantity from one preparation of virus particles to another with this method. 
D)  Yes-only fully functioning viruses will be released from a host cell, so the quantified number of virus particles in a plaque assay should be identical to the number of free virus particles counted by electron microscopy.

Question 8

You are graduating from nursing school in three months and have already lined up a new job. However, your employer informs you that before you start your job, it is mandatory for you to be vaccinated against hepatitis B, a double-stranded DNA virus that can cause the disease hepatitis. Your boyfriend, a biology major, wonders why you need to get the vaccine. You aced your microbiology class and you know a lot about both viruses and vaccines, so you understand why getting this vaccination is essential. You give your boyfriend a mini lesson on this by answering a few of his questions.
-You friend wonders whether the same type of virus can cause both an acute and a persistent infection? You answer

Accepted Answer

A)  Yes-the initial infection might be acute but the virus can later become latent by becoming integrated into the host cell genome. 
B)  No-a virus causes either an acute infection or a persistent infection, but never both. 
C)  No-if the initial infection is acute, the virus would have to mutate in the host before being able to cause a persistent infection. 
D)  Yes-acute and persistent infections are really the same thing except that people with persistent infections recover more quickly than those with acute infections. 
E)  Yes-acute and persistent infections are really the same thing except that people with acute infections recover more quickly than those with persistent infections. 
A)  Yes-the initial infection might be acute but the virus can later become latent by becoming integrated into the host cell genome. 
B)  No-a virus causes either an acute infection or a persistent infection, but never both. 
C)  No-if the initial infection is acute, the virus would have to mutate in the host before being able to cause a persistent infection. 
D)  Yes-acute and persistent infections are really the same thing except that people with persistent infections recover more quickly than those with acute infections. 
E)  Yes-acute and persistent infections are really the same thing except that people with acute infections recover more quickly than those with persistent infections.

Question 9

You are graduating from nursing school in three months and have already lined up a new job. However, your employer informs you that before you start your job, it is mandatory for you to be vaccinated against hepatitis B, a double-stranded DNA virus that can cause the disease hepatitis. Your boyfriend, a biology major, wonders why you need to get the vaccine. You aced your microbiology class and you know a lot about both viruses and vaccines, so you understand why getting this vaccination is essential. You give your boyfriend a mini lesson on this by answering a few of his questions.
-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 10

The site at which a virus has infected and subsequently lysed the infected cell, releasing its progeny to infect and lyse surrounding cells, thereby forming a "clear zone," is

Accepted Answer

A)  a burst area. 
B)  a lyse area. 
C)  a plaque. 
D)  a dead zone. 
E)  a zone of inhibition. 
A)  a burst area. 
B)  a lyse area. 
C)  a plaque. 
D)  a dead zone. 
E)  a zone of inhibition.

Question 11

Prions

Accepted Answer

A)  consist of a special nucleocapsid. 
B)  are made of protein only. 
C)  are made of RNA only. 
D)  are made of dsRNA and protein. 
E)  consist of proteins and phospholipids. 
A)  consist of a special nucleocapsid. 
B)  are made of protein only. 
C)  are made of RNA only. 
D)  are made of dsRNA and protein. 
E)  consist of proteins and phospholipids.

Question 12

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

Accepted Answer

A) True 
 B)False

Question 13

In addition to lysis, animal viruses may exit the host cell by

Accepted Answer

A)  extrusion. 
B)  budding. 
C)  fission. 
D)  fusion. 
E)  endocytosis. 
A)  extrusion. 
B)  budding. 
C)  fission. 
D)  fusion. 
E)  endocytosis.

Question 14

Phages that can either replicate and cause cell lysis or can integrate their DNA into the host DNA are called

Accepted Answer

A)  temperate phages. 
B)  lytic phages. 
C)  virulent phages. 
D)  segmented phages. 
E)  bacteriophages. 
A)  temperate phages. 
B)  lytic phages. 
C)  virulent phages. 
D)  segmented phages. 
E)  bacteriophages.

Question 15

Which of the following BEST describes the protein coat of a virus? It

Accepted Answer

A)  is called a capsomere, AND is involved in the recognition of host cell receptors by non-enveloped viruses. 
B)  is called a capsid, AND is involved in the recognition of host cell receptors by non-enveloped viruses. 
C)  protects the nucleic acid, AND is involved in the recognition of host cell receptors by non-enveloped viruses. 
D)  is called a capsomere, protects the nucleic acid, AND is involved in the recognition of host cell receptors by non-enveloped viruses. 
E)  is called a capsid, protects the nucleic acid, AND is involved in the recognition of host cell receptors by non-enveloped viruses. 
A)  is called a capsomere, AND is involved in the recognition of host cell receptors by non-enveloped viruses. 
B)  is called a capsid, AND is involved in the recognition of host cell receptors by non-enveloped viruses. 
C)  protects the nucleic acid, AND is involved in the recognition of host cell receptors by non-enveloped viruses. 
D)  is called a capsomere, protects the nucleic acid, AND is involved in the recognition of host cell receptors by non-enveloped viruses. 
E)  is called a capsid, protects the nucleic acid, AND is involved in the recognition of host cell receptors by non-enveloped viruses.

Question 16

Once integrated, phage DNA can remain in the prophage state as long as

Accepted Answer

A)  the bacteria is frequently plated on new media. 
B)  certain phage genes are excised. 
C)  certain phage genes are repressed. 
D)  bacterial repressor genes are activated. 
E)  bacterial repressor genes are deactivated. 
A)  the bacteria is frequently plated on new media. 
B)  certain phage genes are excised. 
C)  certain phage genes are repressed. 
D)  bacterial repressor genes are activated. 
E)  bacterial repressor genes are deactivated.

Question 17

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 18

Enveloped viruses

Accepted Answer

A)  never use spikes for attachment to host cells. 
B)  have a lipid bilayer membrane containing various proteins. 
C)  are surrounded by an additional layer of carbohydrate. 
D)  surround the boundary of a host cell. 
E)  are difficult to destroy using detergents. 
A)  never use spikes for attachment to host cells. 
B)  have a lipid bilayer membrane containing various proteins. 
C)  are surrounded by an additional layer of carbohydrate. 
D)  surround the boundary of a host cell. 
E)  are difficult to destroy using detergents.

Question 19

All viruses must separate the nucleic acid from the capsid before replication.

Accepted Answer

A) True 
 B)False

Question 20

Diseases of short duration frequently followed by long-term immunity are referred to as

Accepted Answer

A)  intermittent infections. 
B)  chronic infections. 
C)  acute infections. 
D)  persistent infections. 
E)  nonacute infections. 
A)  intermittent infections. 
B)  chronic infections. 
C)  acute infections. 
D)  persistent infections. 
E)  nonacute infections.

Exam 13: Viruses, Viroids, and Prions

Which of the following is NOT True of prions?

You add an unknown phage to a mixture of F⁺ and F− cells of E. coli and plate out the bacteria. The bacterial colonies that grow are all F−. How can you explain this phenomenon?

The time from absorption to release for T-even phage is about

Plant viruses enter the host plant via

During penetration of E. coli by the T4 phage,

The best-known examples of viruses that cause latent infections are

Would you expect the number of virions to be the same if you measured them by the plaque assay or by counting using the electron microscope? Why?

The site at which a virus has infected and subsequently lysed the infected cell, releasing its progeny to infect and lyse surrounding cells, thereby forming a "clear zone," is

Prions

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

In addition to lysis, animal viruses may exit the host cell by

Phages that can either replicate and cause cell lysis or can integrate their DNA into the host DNA are called

Which of the following BEST describes the protein coat of a virus? It

Once integrated, phage DNA can remain in the prophage state as long as

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

Enveloped viruses

All viruses must separate the nucleic acid from the capsid before replication.

Diseases of short duration frequently followed by long-term immunity are referred to as

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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