Question 1

The main function of a host cell receptor is to specifically bind to the viral attachment protein.

Accepted Answer

A) True 
 B)False  False

Question 2

Most enveloped viruses exit the cell by the following process

Accepted Answer

A)   exocytosis.
B)   budding.
C)   Golgi transport.
D)   cell lysis.
E)   cytokinesis. B

Question 3

Class III viruses,double-stranded RNA viruses,utilize the following polymerase for genome synthesis

Accepted Answer

A)   host cell RNA-dependent RNA polymerase.
B)   host cell DNA-dependent RNA polymerase.
C)   viral RNA-dependent RNA polymerase.
D)   viral DNA-dependent RNA polymerase.
E)   viral DNA-dependent DNA polymerase. C

Question 4

Class V viruses,negative sense single-stranded RNA viruses,utilize the following polymerase for mRNA synthesis

Accepted Answer

A)   viral DNA-dependent RNA polymerase.
B)   host cell RNA-dependent RNA polymerase.
C)   host cell DNA-dependent RNA polymerase.
D)   viral RNA-dependent RNA polymerase.
E)   don't need polymerase, nucleic acid can act directly as mRNA.

Question 5

A nucleoside analog is a short nucleotide sequence that is complementary to a viral promoter sequence.

Accepted Answer

A) True 
 B)False

Question 6

Most non-enveloped viruses exit the cell by the following process

Accepted Answer

A)   exocytosis.
B)   budding.
C)   Golgi transport.
D)   cell lysis.
E)   cytokinesis.

Question 7

The second step in viral replication,"entry",is prevented by some antiviral drugs.

Accepted Answer

A) True 
 B)False

Question 8

E)coli strain K12 is susceptible to infection by phage T2.T2 binds to K12 via two attachment proteins.These two proteins specifically bind to the following two host cell receptor proteins found on the surface of strain K12.

Accepted Answer

A)   lipopolysaccharide and cytochrome c
B)   flagellin and cytochrome c
C)   OmpF and lipopolysaccharide
D)   OmpF and flagellin
E)   flagellin and lipopolysaccharide

Question 9

Bacteriophage T4 lyses the bacterial host cell for release of newly formed virions.The cell wall of the bacterium is broken down by this virally encoded enzyme

Accepted Answer

A)   lysozyme.
B)   protease.
C)   β-lactamase.
D)   nuclease.
E)   peptidase.

Question 10

Antiviral drugs that act at the level of host recognition are designed to

Accepted Answer

A)   prevent endocytotic vesicle formation.
B)   prevent virus binding to the host cell receptor.
C)   enhance antibody production.
D)   inactivate viral nucleic acid polymerases.
E)   bind to viral metabolic enzymes.

Question 11

Drugs that inhibit the acidification of the endosome block the replication of many viruses that enter the cell through receptor-mediated endocytosis.Why are these drugs effective?

Accepted Answer

The answer of Drugs that inhibit the acidification of the...

Question 12

The viral attachment protein specifically binds to a host cell receptor.All of the following are examples of known host cell receptors except

Accepted Answer

A)   DNA.
B)   proteins.
C)   glycoproteins.
D)   lipopolysaccharides.
E)   sialic acids.

Question 13

The reason nucleoside analogs are effective against viral nucleic acid polymerases is because

Accepted Answer

A)   viral polymerases have a very high rates of polymerization.
B)   viral polymerases have a low rate of polymerization.
C)   viral polymerases have a high affinity for incorporation of the analogs.
D)   viral polymerase activity is inhibited by the analogs.
E)   viral polymerase activity is enhanced by the analogs.

Question 14

Fuzeon is an antiviral drug that prevents membrane fusion for entry into the cell by HIV.The mode of action for this drug is

Accepted Answer

A)   to prevent formation of a viral lipase that lyses the cell membrane.
B)   to prevent attachment of the virus to the host cell receptor.
C)   to interrupt receptor mediated endocytosis.
D)   to bind to gp41 membrane fusion protein of HIV.
E)   to digest the envelope of HIV, thereby preventing membrane fusion.

Question 15

The Baltimore classification scheme classifies viruses based on their mechanism of mRNA synthesis.Using this classification scheme,all viruses are placed into ______ classes.

Accepted Answer

A)   seven
B)   five
C)   four
D)   ten
E)   twenty five

Question 16

AZT is a nucleotide analog used to treat people infected with

Accepted Answer

A)   herpes virus.
B)   HIV.
C)   papilloma virus.
D)   influenza virus.
E)   polio virus.

Question 17

Protease inhibitors are routinely used in the treatment of an HIV infection to slow down the progression of the disease.How do these inhibitors work?

Accepted Answer

A)   They inhibit the process of translation for the production of viral proteins.
B)   They inhibit the process of entry by interacting with the fusion peptide.
C)   They block the attachment process by interacting with the viral attachment protein.
D)   They inhibit the proteolytic modification of the viral capsid to form an infectious virion.
E)   They inhibit the activity of the viral enzyme reverse transcriptase.

Question 18

Antibody produced in response to a viral infection is able to neutralize viral attachment by

Accepted Answer

A)   binding nucleic acid polymerases and preventing viral nucleic acid replication.
B)   binding ribosomes and preventing viral protein translation.
C)   activating macrophages to phagocytize the virus.
D)   binding to the viral attachment proteins to prevent attachment to the host cell receptor.
E)   binding to the host cell receptor molecule to prevent the attachment of the virus.

Question 19

The ability of a virus or bacteriophage to specifically attach to a host cell occurs through the interactions of the viral attachment protein with the host cell receptor.This binding determines

Accepted Answer

A)   the rate of viral replication.
B)   the host range.
C)   the mechanism of viral entry.
D)   whether or not the virus will contain an envelope.
E)   the rate of viral RNA replication.

Question 20

For most double-stranded DNA eukaryal viruses,DNA replication occurs in the _________ and translation occurs in the __________.

Accepted Answer

A)   cytoplasm, cytoplasm
B)   cytoplasm, nucleus
C)   nucleus, nucleus
D)   nucleus, cytoplasm
E)   mitochondria, cytoplasm

Exam 8: Viral Replication Strategies