Question 1

Please select the True statement regarding bacteriophage life cycles.

Accepted Answer

A)  Temperate phages lyse their host cells, whereas lytic phages either lyse their host or integrate their DNA into the host cell's genome. 
B)  Lytic phages lyse their host cells, whereas temperate phages either lyse their host or integrate their DNA into the host cell's genome. 
C)  In the bacteriophage life cycle, the entire virus enters the host bacterial cell through a hole in the cell wall. 
D)  Phage particles seek out their bacterial hosts by means of chemotaxis and then attach to random receptors on the host's cell wall. 
E)  The burst size is the number of bacterial cells that are lysed as a result of being infected by a bacteriophage such as T4. 
A)  Temperate phages lyse their host cells, whereas lytic phages either lyse their host or integrate their DNA into the host cell's genome. 
B)  Lytic phages lyse their host cells, whereas temperate phages either lyse their host or integrate their DNA into the host cell's genome. 
C)  In the bacteriophage life cycle, the entire virus enters the host bacterial cell through a hole in the cell wall. 
D)  Phage particles seek out their bacterial hosts by means of chemotaxis and then attach to random receptors on the host's cell wall. 
E)  The burst size is the number of bacterial cells that are lysed as a result of being infected by a bacteriophage such as T4. B

Question 2

Why is it not surprising that AIDS patients frequently suffer a viral-induced tumor?

Accepted Answer

A)  HIV genomes integrate into the host cell chromosome. This integration might result in loss of control of the cell cycle (also known as cancer). 
B)  The immune system's CD4⁺ T cells are directly responsible for elimination of tumor cells. HIV attacks them and eliminates them, making a person more susceptible to cancer. 
C)  The therapies for HIV are highly mutagenic, which may lead to cancerous states in people taking the drug regimen. 
D)  Products of an active HIV infection are highly mutagenic; as a person's illness progresses, these compounds build up and induce a cancerous state. 
E)  The DNA polymerases of people with AIDS lose any proofreading ability, so any mistakes that happen during DNA replication automatically lead to development of cancer. 
A)  HIV genomes integrate into the host cell chromosome. This integration might result in loss of control of the cell cycle (also known as cancer). 
B)  The immune system's CD4⁺ T cells are directly responsible for elimination of tumor cells. HIV attacks them and eliminates them, making a person more susceptible to cancer. 
C)  The therapies for HIV are highly mutagenic, which may lead to cancerous states in people taking the drug regimen. 
D)  Products of an active HIV infection are highly mutagenic; as a person's illness progresses, these compounds build up and induce a cancerous state. 
E)  The DNA polymerases of people with AIDS lose any proofreading ability, so any mistakes that happen during DNA replication automatically lead to development of cancer. A

Question 3

During attachment of phage to E. coli, the phage

Accepted Answer

A)  actively seeks out the bacteria AND attaches to proteins or carbohydrates on the bacterial surface. 
B)  randomly bumps into the bacteria AND attaches to proteins or carbohydrates on the bacterial surface. 
C)  randomly bumps into the bacteria AND attaches to the bacterial RNA. 
D)  randomly bumps into the bacteria AND attaches to the bacterial DNA. 
E)  actively seeks out the bacteria AND attaches to the bacterial DNA. 
A)  actively seeks out the bacteria AND attaches to proteins or carbohydrates on the bacterial surface. 
B)  randomly bumps into the bacteria AND attaches to proteins or carbohydrates on the bacterial surface. 
C)  randomly bumps into the bacteria AND attaches to the bacterial RNA. 
D)  randomly bumps into the bacteria AND attaches to the bacterial DNA. 
E)  actively seeks out the bacteria AND attaches to the bacterial DNA. B

Question 4

Infective and non-infective viruses may be distinguished by growth on MacConkey's agar.

Accepted Answer

A) True 
 B)False

Question 5

Resistance of some animals to certain viral diseases is based on

Accepted Answer

A)  lack of spikes for attachment. 
B)  lack of specific receptors on the host cell. 
C)  phagocytosis of the virus by the host cell. 
D)  the presence of the viral envelope. 
E)  immunity in the host cell. 
A)  lack of spikes for attachment. 
B)  lack of specific receptors on the host cell. 
C)  phagocytosis of the virus by the host cell. 
D)  the presence of the viral envelope. 
E)  immunity in the host cell.

Question 6

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 7

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 tell your friend that you are happy to be receiving your vaccination because hepatitis B is associated with hepatocellular carcinoma (liver cancer). Select the False statement regarding viruses and cancer.

Accepted Answer

A)  Viruses that lead to cancer formation are called oncogenic viruses. 
B)  The most common viral causes of tumors are certain DNA viruses such as hepatitis B virus. 
C)  Some viruses carry an oncogene-infection with these viruses interferes with the host cell's own growth-control mechanisms. 
D)  The majority of tumors are caused by oncogenic viruses but some may be caused by mutations in host genes that regulate cell growth. 
E)  Viruses that insert their genome into the host cell's chromosome may cause changes at the insertion site, converting a proto-oncogene into an oncogene. 
A)  Viruses that lead to cancer formation are called oncogenic viruses. 
B)  The most common viral causes of tumors are certain DNA viruses such as hepatitis B virus. 
C)  Some viruses carry an oncogene-infection with these viruses interferes with the host cell's own growth-control mechanisms. 
D)  The majority of tumors are caused by oncogenic viruses but some may be caused by mutations in host genes that regulate cell growth. 
E)  Viruses that insert their genome into the host cell's chromosome may cause changes at the insertion site, converting a proto-oncogene into an oncogene.

Question 8

Carriers

Accepted Answer

A)  may have a persistent infection. 
B)  may be a source of infection. 
C)  usually show symptoms of the disease AND may be a source of infection. 
D)  have been cured of the infection. 
E)  may have a persistent infection AND may be a source of infection. 
A)  may have a persistent infection. 
B)  may be a source of infection. 
C)  usually show symptoms of the disease AND may be a source of infection. 
D)  have been cured of the infection. 
E)  may have a persistent infection AND may be a source of infection.

Question 9

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

Accepted Answer

A)  2 
B)  5 
C)  7 
D)  13 
E)  6 
A)  2 
B)  5 
C)  7 
D)  13 
E)  6

Question 10

In the case of T-even phages, the burst size is about

Accepted Answer

A)  1 per host cell. 
B)  5 per host cell. 
C)  20 per host cell. 
D)  200 per host cell. 
E)  1,000 per host cell. 
A)  1 per host cell. 
B)  5 per host cell. 
C)  20 per host cell. 
D)  200 per host cell. 
E)  1,000 per host cell.

Question 11

The terms helical, icosahedral, and complex refer to

Accepted Answer

A)  viral life cycles. 
B)  forms of nucleic acid. 
C)  types of viral envelopes. 
D)  shapes of viruses. 
E)  types of bacteriophages. 
A)  viral life cycles. 
B)  forms of nucleic acid. 
C)  types of viral envelopes. 
D)  shapes of viruses. 
E)  types of bacteriophages.

Question 12

Which of the following is not a characteristic of normal cells?

Accepted Answer

A)  They grow as a monolayer. 
B)  They grow as multiple layers. 
C)  They undergo a limited number of divisions and then die. 
D)  They stick tightly to the surface of glass culture dishes. 
E)  These are all characteristics of normal cells. 
A)  They grow as a monolayer. 
B)  They grow as multiple layers. 
C)  They undergo a limited number of divisions and then die. 
D)  They stick tightly to the surface of glass culture dishes. 
E)  These are all characteristics of normal cells.

Question 13

The genome of retroviruses is made of

Accepted Answer

A)  ssDNA. 
B)  dsDNA. 
C)  ssRNA. 
D)  dsRNA. 
E)  protein and RNA. 
A)  ssDNA. 
B)  dsDNA. 
C)  ssRNA. 
D)  dsRNA. 
E)  protein and RNA.

Question 14

A temperate phage

Accepted Answer

A)  may be lysogenic. 
B)  may be lytic. 
C)  enters a lysogenic or lytic life cycle shortly after entering the host cell. 
D)  may be lytic AND enters a lysogenic or lytic life cycle shortly after entering the host cell. 
E)  may be lysogenic AND enters a lysogenic or lytic life cycle shortly after entering the host cell. 
A)  may be lysogenic. 
B)  may be lytic. 
C)  enters a lysogenic or lytic life cycle shortly after entering the host cell. 
D)  may be lytic AND enters a lysogenic or lytic life cycle shortly after entering the host cell. 
E)  may be lysogenic AND enters a lysogenic or lytic life cycle shortly after entering the host cell.

Question 15

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

Accepted Answer

A) True 
 B)False

Question 16

The concentration of virus that infects or kills 50% of the host cells is referred to as the

Accepted Answer

A)  LD₅₀ 
B)  ID₅₀ 
C)  ID₁₀₀ 
D)  LD₁₀₀ AND ID₁₀₀ 
E)  LD₅₀ AND ID₅₀ 
A)  LD₅₀ 
B)  ID₅₀ 
C)  ID₁₀₀ 
D)  LD₁₀₀ AND ID₁₀₀ 
E)  LD₅₀ AND ID₅₀

Question 17

When a non-enveloped animal virus adsorbs to the host cell with its protein spikes, the virions are taken into the cell by the process of

Accepted Answer

A)  penetration. 
B)  production. 
C)  endocytosis. 
D)  fusion. 
E)  budding. 
A)  penetration. 
B)  production. 
C)  endocytosis. 
D)  fusion. 
E)  budding.

Question 18

Once inside the host cell, phage DNA

Accepted Answer

A)  is replicated. 
B)  is transcribed. 
C)  may get degraded by bacterial nucleases. 
D)  may integrate into the host chromosome. 
E)  All of the choices are correct. 
A)  is replicated. 
B)  is transcribed. 
C)  may get degraded by bacterial nucleases. 
D)  may integrate into the host chromosome. 
E)  All of the choices are correct.

Question 19

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 20

If you had three tubes of flu viruses and you exposed tube 1 to protease, tube 2 to protease and RNase, and tube 3 to protease and DNase, and the contents of tube 2 were be degraded, you would be able to conclude that

Accepted Answer

A)  an RNA virus. 
B)  a DNA virus. 
C)  a protein virus. 
D)  resistant to proteases. 
E)  an opportunist. 
A)  an RNA virus. 
B)  a DNA virus. 
C)  a protein virus. 
D)  resistant to proteases. 
E)  an opportunist.

Exam 13: Viruses, Viroids, and Prions

Please select the True statement regarding bacteriophage life cycles.

Why is it not surprising that AIDS patients frequently suffer a viral-induced tumor?

During attachment of phage to E. coli, the phage

Infective and non-infective viruses may be distinguished by growth on MacConkey's agar.

Resistance of some animals to certain viral diseases is based on

Spongiform encephalopathy occurs in all of the following EXCEPT

Carriers

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

In the case of T-even phages, the burst size is about

The terms helical, icosahedral, and complex refer to

Which of the following is not a characteristic of normal cells?

The genome of retroviruses is made of

A temperate phage

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

The concentration of virus that infects or kills 50% of the host cells is referred to as the

When a non-enveloped animal virus adsorbs to the host cell with its protein spikes, the virions are taken into the cell by the process of

Once inside the host cell, phage DNA

The term "segmented" refers to viruses that

If you had three tubes of flu viruses and you exposed tube 1 to protease, tube 2 to protease and RNase, and tube 3 to protease and DNase, and the contents of tube 2 were be degraded, you would be able to conclude that

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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