Question 1

Filamentous virus is incapable of causing a lytic infection.

Accepted Answer

A) True 
 B)False

Question 2

Why is it virtually impossible to stamp out a disease caused by a zoonotic virus?

Accepted Answer

A)  You'd have to drive the vector organism extinct to do so.
B)  Many vector organisms have multiple stages of their life cycle that can carry a zoonotic virus, which complicates controlling the vector-borne transmission.
C)  Many viruses transmitted in this manner may utilize more than one vector organism.
D)  Many zoonotic viruses may be able to reside in more than 1 host organism, complicating control measures.
E)  All of the above are correct.F) C) and E)
G) C) and D)

Question 3

Why do animal viruses have envelopes and phages rarely do?

Accepted Answer

A)  Since bacteria don't have cell membranes, the bacterial viruses (phages)  don't pick them up when they leave the target cells.
B)  Phages acquire an outer surrounding that is a part of the cell wall of the bacterium they were created in, rather than an outer surrounding of plasma membrane.
C)  Animal viruses will often utilize the envelope in order to fuse with the plasma membrane of a new target cell, gaining entry into the cytoplasm.
D)  Animal viruses build the envelope inside of the target cell as they are being replicated, but before the cell breaks open and releases them into the extracellular environment.The envelope is a remnant of this building process.E) None of the above
F) A) and B)

Question 4

In the region of budding, the plasma membrane becomes involved with

Accepted Answer

A)  carbohydrates.
B)  spike proteins.
C)  matrix proteins.
D)  enzymes.
E)  spike proteins AND matrix proteins.F) D) and E)
G) C) and D)

Question 5

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

Accepted Answer

A.The virus is an RNA genome virus-by us...

Question 6

What is a defective phage?

Accepted Answer

A)  A virus that has lost some of its genetic material, and therefore cannot infect a new target cell.
B)  A virus that has lost some of its genetic material, and therefore cannot replicate within a new target cell.
C)  A virus that lacks the ability to replicate independently of its host cell.
D)  A virus that cannot attach to its host cell.E) B) and C)
F) None of the above

Question 7

What are two ways that phage can replicate in harmony (not directly lysing)  their host cell?

Accepted Answer

A)  conjugation and lysogeny
B)  lysogeny and transduction
C)  extrusion and transformation
D)  extrusion and lysogenyE) None of the above
F) A) and B)

Question 8

What part of the attached bacteriophage enters through the host cell wall?

Accepted Answer

A)  the entire virus
B)  only the enzymes necessary for replication
C)  the nucleic acid
D)  the nucleic acid and capsid
E)  the capsid onlyF) A) and C)
G) B) and C)

Question 9

The family to which the Rhinovirus belongs is the

Accepted Answer

A)  Picornaviridae.
B)  Enterovirus.
C)  Enteroviridae.
D)  Picornavirus.E) A) and B)
F) A) and C)

Question 10

Why are viroids resistant to nucleases?
A.Having a circular RNA 'genome,' they are resistant to the digestion of most exonucleases (that nibble/digest the free ends of RNA or DNA).
B.Having a circular RNA 'genome,' with no protein shell, they are resistant to the protein-degrading activities of nucleases.
C.Nucleases will only digest DNA, not RNA-so viroids are protected.
D.Viroids have only been identified in plants.Plant nucleases cannot digest RNA.

Accepted Answer

A.Having a circular RNA 'genome,' they a...

Question 11

Would ID50 and LD50 necessarily be the same for a given virus? Why or why not?
A.Yes, because the number of viruses that infect 50% of a test population should also kill 50% of that test population.
B.No, because a virus may be highly infectious (very low ID50 value) but only marginally lethal (very high LD50 value).A prime example of this is the rhinovirus (common cold virus).
C.No, because very few viruses are lethal, yet many are highly infectious.The 2 values should ALWAYS be different.
D.Yes, because what we're actually describing here is infection/killing of individual CELLS, not of entire organisms.If a cell is infected, it will always be killed.

Accepted Answer

A.Yes, because the number of viruses tha...

Question 12

The correct order for the stages of a phage infection is:

Accepted Answer

A)  penetration, transcription, attachment, replication of nucleic acid and protein, assembly, release
B)  attachment, penetration, transcription, replication of nucleic acid and protein, assembly, release
C)  attachment, replication of nucleic acid and protein, penetration, transcription, assembly, release
D)  transcription, attachment replication of nucleic acid and protein, assembly, penetration, releaseE) B) and D)
F) A) and B)

Question 13

The shape of the virus is determined by its

Accepted Answer

A)  nucleic acid.
B)  capsid.
C)  envelope.
D)  tail.E) A) and B)
F) A) and C)

Question 14

There are _______ families of DNA containing viruses that infect vertebrates.

Accepted Answer

A)  two
B)  four
C)  five
D)  sevenE) A) and D)
F) A) and C)

Question 15

Viruses that infect bacteria are referred to as

Accepted Answer

A)  viralcidens.
B)  bacteriocidins.
C)  bacterialogens.
D)  bacteriophages.E) A) and D)
F) A) and C)

Question 16

Virulent as well as temperate phages can serve as generalized transducing phages.

Accepted Answer

A) True 
 B)False

Question 17

An infection in which the virus is continually present in the body is referred to as

Accepted Answer

A)  acute.
B)  balanced.
C)  determinant.
D)  persistent.E) A) and B)
F) A) and C)

Question 18

Is antigenic shift alone likely to lead to influenza pandemics?

Accepted Answer

A)  Yes-ONLY antigenic shift can lead to the large-scale mixing of gene elements required to produce a pandemic flu strain.
B)  No-ONLY antigenic DRIFT can lead to the large-scale mixing of gene elements required to produce a pandemic flu strain.
C)  Perhaps-but it would most likely be a mixture of antigenic shift AND drift that would result in a pandemic strain.
D)  No-antigenic SHIFT is responsible for changes in the hemagglutinin protein, while antigenic DRIFT is responsible for changes in the neuraminidase protein.You must have changes in both to lead to a pandemic strain.E) A) and C)
F) B) and D)

Question 19

Genetic exchange in segmented viruses that allows a zoonotic virus to infect humans is termed

Accepted Answer

A)  antigenic shift.
B)  hemagglutination.
C)  genetic reassortment.
D)  antigenic drift.E) C) and D)
F) None of the above

Question 20

Capsids are made of a number of capsomeres which are covalently bonded to one another.

Accepted Answer

A) True 
 B)False

Exam 13: Viruses, Viroids and Prions

The family to which the Rhinovirus belongs is the

Correct Answer
verified

Virulent as well as temperate phages can serve as generalized transducing phages.

Correct Answer
verified

Why do animal viruses have envelopes and phages rarely do?

Correct Answer
verified

Correct Answer
verified
A.The virus is an RNA genome virus-by us...
View Answer

Viruses that infect bacteria are referred to as

Correct Answer
verified

In the region of budding, the plasma membrane becomes involved with

Correct Answer
verified

An infection in which the virus is continually present in the body is referred to as

Correct Answer
verified

Filamentous virus is incapable of causing a lytic infection.

Correct Answer
verified

The correct order for the stages of a phage infection is:

Correct Answer
verified

There are _______ families of DNA containing viruses that infect vertebrates.

Correct Answer
verified

Correct Answer
verified
A.Having a circular RNA 'genome,' they a...
View Answer

Why is it virtually impossible to stamp out a disease caused by a zoonotic virus?

Correct Answer
verified

Genetic exchange in segmented viruses that allows a zoonotic virus to infect humans is termed

Correct Answer
verified

Capsids are made of a number of capsomeres which are covalently bonded to one another.

Correct Answer
verified

Correct Answer
verified
A.Yes, because the number of viruses tha...
View Answer

What is a defective phage?

Correct Answer
verified

What are two ways that phage can replicate in harmony (not directly lysing) their host cell?

Correct Answer
verified

Is antigenic shift alone likely to lead to influenza pandemics?

Correct Answer
verified

What part of the attached bacteriophage enters through the host cell wall?

Correct Answer
verified

The shape of the virus is determined by its

Correct Answer
verified

Exam 13: Viruses, Viroids and Prions

The family to which the Rhinovirus belongs is the

Correct AnswerverifiedShow Answer

Virulent as well as temperate phages can serve as generalized transducing phages.

Correct AnswerverifiedShow Answer

Why do animal viruses have envelopes and phages rarely do?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedA.The virus is an RNA genome virus-by us...View AnswerShow Answer

Viruses that infect bacteria are referred to as

Correct AnswerverifiedShow Answer

In the region of budding, the plasma membrane becomes involved with

Correct AnswerverifiedShow Answer

An infection in which the virus is continually present in the body is referred to as

Correct AnswerverifiedShow Answer

Filamentous virus is incapable of causing a lytic infection.

Correct AnswerverifiedShow Answer

The correct order for the stages of a phage infection is:

Correct AnswerverifiedShow Answer

There are _______ families of DNA containing viruses that infect vertebrates.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedA.Having a circular RNA 'genome,' they a...View AnswerShow Answer

Why is it virtually impossible to stamp out a disease caused by a zoonotic virus?

Correct AnswerverifiedShow Answer

Genetic exchange in segmented viruses that allows a zoonotic virus to infect humans is termed

Correct AnswerverifiedShow Answer

Capsids are made of a number of capsomeres which are covalently bonded to one another.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedA.Yes, because the number of viruses tha...View AnswerShow Answer

What is a defective phage?

Correct AnswerverifiedShow Answer

What are two ways that phage can replicate in harmony (not directly lysing) their host cell?

Correct AnswerverifiedShow Answer

Is antigenic shift alone likely to lead to influenza pandemics?

Correct AnswerverifiedShow Answer

What part of the attached bacteriophage enters through the host cell wall?

Correct AnswerverifiedShow Answer

The shape of the virus is determined by its

Correct AnswerverifiedShow Answer

Correct Answer
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Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
A.The virus is an RNA genome virus-by us...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
A.Having a circular RNA 'genome,' they a...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
A.Yes, because the number of viruses tha...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
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