Question 1

All of the following are diseases caused by viruses except

Accepted Answer

A)  strep throat.
B)  AIDS.
C)  polio.
D)  small pox.
E)  measles.F) B) and C)
G) C) and D)

Question 2

Vibrio cholerae lives in water and gets toxin genes from a virus by phage conversion.The toxin kills the intestinal epithelial cells in the human host,resulting in massive diarrhea.Untreated cholera has about a 50% mortality rate.How do the bacteria benefit?

Accepted Answer

A)  Diarrhea helps the bacteria to spread from person to person.
B)  Killing humans provides nutrients for the bacteria.
C)  They don't -- humans are not the main host and their symptoms are maladaptive for the bacteria.
D)  The bacteria reproduce faster in a dead human.E) None of the above
F) A) and D)

Question 3

Retroviruses are unique because they are a combination of RNA and DNA.

Accepted Answer

A) True 
 B)False

Question 4

A doctor's office has run out of the latest flu vaccine,but many patients are asking for it.One of the nurses finds some vials from last year's batch in a refrigerator.Should they be used?

Accepted Answer

A)  Yes,because the preservatives and refrigeration ensure that the vaccine is still fresh.
B)  No,because each year the technology to make a good vaccine improves.
C)  No,because each year the vaccine is made against different subtypes of the flu virus.
D)  Maybe - the vaccine should be mixed in a test tube with the virus to see if it still inactivates it.E) None of the above
F) B) and D)

Question 5

________ infects the CD4+ T cells,which are required for normal immunity.

Accepted Answer

The answer of ________ infects the CD4+ T cells,which are...

Question 6

Nucleotide analogs are a class of drugs that are highly effective against many types of viruses.They work by halting the replication of viral genes.They are equally effective at stopping the spread of prion diseases.

Accepted Answer

A) True 
 B)False

Question 7

Nearly all viruses are constructed of

Accepted Answer

A)  DNA with a protein wrapping,called a capsid.
B)  RNA with a protein wrapping,called a capsid.
C)  either DNA or RNA with a protein wrapping,called a capsid.
D)  either DNA or RNA,however many do not have the capsid.E) A) and C)
F) B) and D)

Question 8

Virulent viruses multiply within infected cells and eventually

Accepted Answer

A)  cause an alternation of generations in the host cell,releasing new viruses.
B)  cause the transformation of the host cell,releasing new viruses.
C)  cause lysis of the host cell,releasing new viruses.
D)  cause the transduction of the host cell,releasing new viruses.
E)  cause a transfer of material from the host cell,releasing new viruses.F) A) and D)
G) A) and C)

Question 9

What kind of pathogen would retain its ability to cause infections after being treated with powerful proteolytic chemicals that would destroy all proteinaceous material?

Accepted Answer

A)  A virus
B)  A prion
C)  A fungus
D)  A bacterium
E)  A viroidF) None of the above
G) D) and E)

Question 10

An experimental chemical has been shown to selectively cleave phosphodiester bonds.How would this affect a virus?

Accepted Answer

A)  Fragment the genome
B)  Digest the capsid
C)  Dissociate the envelope
D)  Alter the host binding site
E)  Hydrolyze the protein coatingF) A) and B)
G) C) and E)

Question 11

Can a virus be killed?

Accepted Answer

A)  Yes,destroying its genome kills it.
B)  No,viruses are capable of self-assembly and cannot be permanently killed.
C)  Yes,separating the genes from the capsid kills it.
D)  No,viruses are nonliving and cannot die.E) B) and D)
F) B) and C)

Question 12

Which class of drugs would be effective against HIV but not against most other pathogenic viruses?

Accepted Answer

A)  Nucleotide analogs that halt replication.
B)  Receptor antagonists that block viral entry.
C)  Non-nucleoside reverse transcriptase inhibitors that block reverse transcription.
D)  Translation inhibitors that stop assembly of viral proteins.E) A) and B)
F) C) and D)

Question 13

Plasma from a sick mouse is filtered across a membrane that has a 200 nm pore size.If the filtrate is still infectious when injected into a healthy mouse,then the pathogen is most likely a(n) :

Accepted Answer

A)  bacterium
B)  archaean
C)  fungus
D)  virus
E)  parasitic wormF) B) and E)
G) A) and D)

Question 14

What is the name for parasitic viral DNA that has been integrated into the chromosome of its bacterial host?

Accepted Answer

A)  prophage
B)  prophase
C)  viroid
D)  virion
E)  arbovirusF) A) and B)
G) A) and C)

Question 15

Which of the following is a virus with an icosahedral head,a capsid that contains primarily three proteins,a connecting neck with a collar and long whiskers,a long tail and a complex base plate?

Accepted Answer

A)  influenza virus
B)  measles virus
C)  T4 bacteriophage
D)  HIV
E)  tuberculosisF) A) and B)
G) D) and E)

Question 16

The pneumonia caused by the influenza virus results from the accumulation of fluid and cell debris in the lungs.This occurs during the lysogenic life cycle of the virus.

Accepted Answer

A) True 
 B)False

Question 17

Viruses are ________ -coated fragments of DNA or RNA.

Accepted Answer

The answer of Viruses are ________ -coated fragments of DNA...

Question 18

Phages are viruses that can infect

Accepted Answer

A)  humans.
B)  plants.
C)  insects.
D)  farm animals.
E)  bacteria.F) A) and C)
G) A) and D)

Question 19

An example of an "emerging virus" (a virus in a new host) with a lethality rate in excess of 50% is

Accepted Answer

A)  influenza virus.
B)  Ebola virus.
C)  hepatitis B.
D)  variola virus.
E)  yellow fever.F) C) and E)
G) A) and B)

Question 20

Once a prophage is present in a bacterial genome,viral genes are reproduced every time the bacterium multiplies.Expression of viral genes,however,is inhibited by a repressor protein.Cell stress can induce the formation of proteases that degrade the repressor.What will result?

Accepted Answer

A)  The virus will enter the lysogenic cycle.
B)  The bacterium will reject the viral genes.
C)  The virus will enter the lytic cycle.
D)  The bacterial genome will be denatured.E) A) and B)
F) A) and C)

Exam 26: Viruses

Can a virus be killed?

Correct AnswerverifiedShow Answer

Virulent viruses multiply within infected cells and eventually

Correct AnswerverifiedShow Answer

Nearly all viruses are constructed of

Correct AnswerverifiedShow Answer

What kind of pathogen would retain its ability to cause infections after being treated with powerful proteolytic chemicals that would destroy all proteinaceous material?

Correct AnswerverifiedShow Answer

Nucleotide analogs are a class of drugs that are highly effective against many types of viruses.They work by halting the replication of viral genes.They are equally effective at stopping the spread of prion diseases.

Correct AnswerverifiedShow Answer

Vibrio cholerae lives in water and gets toxin genes from a virus by phage conversion.The toxin kills the intestinal epithelial cells in the human host,resulting in massive diarrhea.Untreated cholera has about a 50% mortality rate.How do the bacteria benefit?

Correct AnswerverifiedShow Answer

All of the following are diseases caused by viruses except

Correct AnswerverifiedShow Answer

________ infects the CD4+ T cells,which are required for normal immunity.

Correct AnswerverifiedShow Answer

Viruses are ________ -coated fragments of DNA or RNA.

Correct AnswerverifiedShow Answer

A doctor's office has run out of the latest flu vaccine,but many patients are asking for it.One of the nurses finds some vials from last year's batch in a refrigerator.Should they be used?

Correct AnswerverifiedShow Answer

Retroviruses are unique because they are a combination of RNA and DNA.

Correct AnswerverifiedShow Answer

Phages are viruses that can infect

Correct AnswerverifiedShow Answer

What is the name for parasitic viral DNA that has been integrated into the chromosome of its bacterial host?

Correct AnswerverifiedShow Answer

Plasma from a sick mouse is filtered across a membrane that has a 200 nm pore size.If the filtrate is still infectious when injected into a healthy mouse,then the pathogen is most likely a(n) :

Correct AnswerverifiedShow Answer

Once a prophage is present in a bacterial genome,viral genes are reproduced every time the bacterium multiplies.Expression of viral genes,however,is inhibited by a repressor protein.Cell stress can induce the formation of proteases that degrade the repressor.What will result?

Correct AnswerverifiedShow Answer

Which class of drugs would be effective against HIV but not against most other pathogenic viruses?

Correct AnswerverifiedShow Answer

An example of an "emerging virus" (a virus in a new host) with a lethality rate in excess of 50% is

Correct AnswerverifiedShow Answer

An experimental chemical has been shown to selectively cleave phosphodiester bonds.How would this affect a virus?

Correct AnswerverifiedShow Answer

The pneumonia caused by the influenza virus results from the accumulation of fluid and cell debris in the lungs.This occurs during the lysogenic life cycle of the virus.

Correct AnswerverifiedShow Answer

Which of the following is a virus with an icosahedral head,a capsid that contains primarily three proteins,a connecting neck with a collar and long whiskers,a long tail and a complex base plate?

Correct AnswerverifiedShow Answer

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