Question 1

Prions consist of proteins and have no apparent nucleic acid genome.

Accepted Answer

A) True 
 B)False

Question 2

Which of the following is not true of viruses?

Accepted Answer

A)   Viruses are acellular.
B)   Viruses consist of one or more molecules of DNA or RNA enclosed in a coat of protein and sometimes in other more complex layers.
C)   Viruses can exist in two phases: intracellular and extracellular.
D)   Viruses replicate by binary fission.E) A) and B)
F) A) and C)

Question 3

0.2 mls of a 10-4 dilution of a virus preparation yields 90 plaques. What is the number of PFU per ml in the undiluted virus preparation?

Accepted Answer

A)   9.0  ×	imes×  105
B)   4.5  ×	imes×  106
C)   4.5  ×	imes×  107
D)   9.0  ×	imes×  108 E) All of the above
F) A) and D)

Question 4

A complete virus particle is called a

Accepted Answer

A)   capsid.
B)   nucleocapsid.
C)   virion.
D)   cell.E) None of the above
F) B) and C)

Question 5

The simplest viruses consist of

Accepted Answer

A)   RNA only.
B)   Protein only.
C)   RNA or DNA in a protein coat.
D)   RNA or DNA in a protein coat covered with lipid envelope.
E)   RNA, DNA and enzymes in a protein coat with a lipid envelope.F) A) and D)
G) B) and D)

Question 6

Nonenveloped viruses most often gain access to eukaryotic host cells by

Accepted Answer

A)   fusion with the host cell plasma membrane followed by entrance of the nucleocapsid into the cytoplasm.
B)   endocytosis.
C)   pinocytosis.
D)   nucleic acid injection through the plasma membrane.E) C) and D)
F) None of the above

Question 7

Some viruses cause abnormal growth of cells rather than destruction. This is called __________.

Accepted Answer

The answer of Some viruses cause abnormal growth of cells...

Question 8

The function of the viral protein coat is to

Accepted Answer

A)   protect the viral genetic material.
B)   aid in the transfer of the viral genetic material between host cells.
C)   elicit the production of protective antibodies.
D)   protect the viral genetic material and aid in the transfer of the viral genetic material between host cells.E) A) and D)
F) All of the above

Question 9

Which of the following is not true regarding the human hepatitis D virusoid?

Accepted Answer

A)   Its genome is a circular, single-stranded RNA molecule.
B)   It needs a helper virus to infect host cells.
C)   It produces one protein called the delta antigen.
D)   All of the statements are true.E) B) and D)
F) C) and D)

Question 10

The largest viruses known are the

Accepted Answer

A)   herpesviruses.
B)   hepadnaviruses.
C)   adenoviruses.
D)   poxviruses.E) B) and C)
F) B) and D)

Question 11

Enveloped viruses may enter their host cells by fusion of their envelope with the cytoplasmic membrane, thereby depositing their nucleocapsid within the cell.

Accepted Answer

A) True 
 B)False

Question 12

Which of the following is not true of viroids?

Accepted Answer

A)   Viroids are small circular ssRNA molecules.
B)   Viroids have no protein capsids.
C)   Viroid RNA does not serve as mRNA nor does it direct the synthesis of mRNA.
D)   Extracellular viroids have a lipid bilayer envelope.E) B) and C)
F) C) and D)

Question 13

Some complex viruses have icosahedral symmetry in the head region and helical symmetry in the tail. Overall, these viruses are said to have __________ symmetry.

Accepted Answer

A)   bilateral
B)   binal
C)   complex
D)   none of theseE) B) and D)
F) A) and B)

Question 14

The most common capsid morphologies are icosahedral and helical.

Accepted Answer

A) True 
 B)False

Question 15

Hemagglutination is

Accepted Answer

A)   the clumping together of red blood cells in the presence of a viral suspension.
B)   the binding of iron in the process of a viral suspension.
C)   the clumping together of infected cells in the presence of a viral suspension.
D)   none of the choicesE) B) and C)
F) A) and B)

Question 16

Viruses such as MS2 and Qß pack additional information into their genomes through the use of overlapping genes.

Accepted Answer

A) True 
 B)False

Question 17

In an enveloped virus, the part of the virus including the nucleic acid genome and the surrounding protein coat but not the envelope is called the

Accepted Answer

A)   capsid.
B)   nucleocapsid.
C)   matrix.
D)   virion.E) B) and C)
F) A) and B)

Question 18

Virion size ranges from

Accepted Answer

A)   1-40 nm.
B)   10-400 nm.
C)   600- 1,000 nm.
D)   1,000-10,000 nm.E) All of the above
F) A) and B)

Question 19

The nucleic acids carried by viruses usually consist of

Accepted Answer

A)   DNA.
B)   RNA.
C)   either DNA or RNA.
D)   both DNA and RNA simultaneously.E) A) and B)
F) B) and C)

Question 20

Most enveloped viruses use the host __________ membrane as their envelope source.

Accepted Answer

A)   plasma
B)   nuclear
C)   mitochondrial
D)   none of theseE) All of the above
F) C) and D)

Exam 5: Viruses and Other Acellular Infectious Agents

The function of the viral protein coat is to

Correct AnswerverifiedShow Answer

Prions consist of proteins and have no apparent nucleic acid genome.

Correct AnswerverifiedShow Answer

Virion size ranges from

Correct AnswerverifiedShow Answer

Some viruses cause abnormal growth of cells rather than destruction. This is called __________.

Correct AnswerverifiedShow Answer

Which of the following is not true regarding the human hepatitis D virusoid?

Correct AnswerverifiedShow Answer

The simplest viruses consist of

Correct AnswerverifiedShow Answer

A complete virus particle is called a

Correct AnswerverifiedShow Answer

Which of the following is not true of viruses?

Correct AnswerverifiedShow Answer

0.2 mls of a 10-4 dilution of a virus preparation yields 90 plaques. What is the number of PFU per ml in the undiluted virus preparation?

Correct AnswerverifiedShow Answer

Most enveloped viruses use the host __________ membrane as their envelope source.

Correct AnswerverifiedShow Answer

The nucleic acids carried by viruses usually consist of

Correct AnswerverifiedShow Answer

Nonenveloped viruses most often gain access to eukaryotic host cells by

Correct AnswerverifiedShow Answer

Which of the following is not true of viroids?

Correct AnswerverifiedShow Answer

Some complex viruses have icosahedral symmetry in the head region and helical symmetry in the tail. Overall, these viruses are said to have __________ symmetry.

Correct AnswerverifiedShow Answer

The most common capsid morphologies are icosahedral and helical.

Correct AnswerverifiedShow Answer

The largest viruses known are the

Correct AnswerverifiedShow Answer

Hemagglutination is

Correct AnswerverifiedShow Answer

In an enveloped virus, the part of the virus including the nucleic acid genome and the surrounding protein coat but not the envelope is called the

Correct AnswerverifiedShow Answer

Enveloped viruses may enter their host cells by fusion of their envelope with the cytoplasmic membrane, thereby depositing their nucleocapsid within the cell.

Correct AnswerverifiedShow Answer

Viruses such as MS2 and Qß pack additional information into their genomes through the use of overlapping genes.

Correct AnswerverifiedShow Answer

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0.2 mls of a 10^-4 dilution of a virus preparation yields 90 plaques. What is the number of PFU per ml in the undiluted virus preparation?

Correct Answer
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