Question 1

One of the strategies used by poxviruses to inhibit host defenses involves the synthesis of a viral serpin.What is the function of the serpin?

Accepted Answer

A)   It inhibits components of the complement system.
B)   It prevent the presentation of peptides on MHC-I.
C)   It is a soluble receptor for the tumor necrosis factor.
D)   It binds to the PKR kinase and inhibits its activity.
E)   It inhibits a serine protease that activates interleukin-1b.F) B) and D)
G) B) and C)

Question 2

Which of the following describes the process of variolation, which was an early method to prevent smallpox infections?

Accepted Answer

A)   Exposure of children to milkmaids infected with cowpox.
B)   Quarantine of smallpox victims for 40 days.
C)   Use of plant extracts to prevent smallpox infection.
D)   Blowing powdered pock scabs into the nose.
E)   Exposure of young children to people with an active smallpox infection.F) None of the above
G) C) and D)

Question 3

Poxviruses express viral proteins that interfere with all of the following host-defense systems EXCEPT:

Accepted Answer

A)   Interferon induced PKR kinase system.
B)   Complement system.
C)   Interleukin-1 cytokine activation.
D)   Production of antibodies by B lymphocytes.
E)   Tumor-necrosis factor activity.F) A) and B)
G) A) and C)

Question 4

During infection with poxviruses, all of the following proteins are produced from early genes EXCEPT:

Accepted Answer

A)   mRNA processing enzymes.
B)   Viral Intermediate Transcription Factor.
C)   Viral Early Transcription Factor.
D)   Viral DNA-dependent DNA polymerase.
E)   Viral DNA-dependent RNA polymerase.F) B) and D)
G) A) and E)

Question 5

Smallpox was eliminated from the human population through the use of antiviral drugs.

Accepted Answer

A) True 
 B)False

Question 6

Which of the following describes the structure of the vaccinia virus genome?

Accepted Answer

A)   Linear DNA with covalently closed ends.
B)   Linear DNA with free ends.
C)   Linear DNA with protein-bound ends.
D)   Multiple linear DNA segments
E)   Covalently closed circle of DNA.F) B) and D)
G) C) and D)

Question 7

If a purified poxvirus genome was heated to melt the hydrogen bonds holding the two strands of DNA together, which of the following would describe the structure of the genome?

Accepted Answer

A)   Multiple pieces of single-stranded DNA
B)   Two linear pieces of single-stranded DNA
C)   A covalently closed circle of double-stranded DNA.
D)   Two single-strand circles entwined together.
E)   A circle of single-stranded DNA.F) B) and E)
G) A) and B)

Question 8

DNA replication in poxviruses uses a "rolling hairpin" model, similar to the method used by viruses in which of the following families?

Accepted Answer

A)   Parvoviruses
B)   Polyomaviruses
C)   Adenoviruses
D)   Herpesviruses
E)   BaculovirusesF) A) and E)
G) None of the above A

Question 9

The mRNAs of poxviruses do not undergo splicing.Which of the following explains why?

Accepted Answer

A)   Poxvirus genomes are small and they need to conserve genome space.
B)   Poxviruses replicate in the cytoplasm of infected cells.
C)   They do not need to regulate gene expression through alternative splicing.
D)   They do not encode the proteins that carry out mRNA splicing.
E)   Poxvirus mRNAs do not contain exons.F) B) and C)
G) A) and B)

Question 10

Intermediate and late transcripts from poxviruses have a unique "poly(A) head" near the 5' end of the mRNA.What is the proposed function for this structure?

Accepted Answer

A)   It binds to the poly(
A)   tails at the 3' end of the mRNA.
B)   It stabilizes and protects the 5' end of the genome.
C)   It aids in recognition of the AUG start codon by ribosomes.
D)   It helps the nascent transcript bind to the viral RNA polymerase during transcription.
E)   It associates with the cap binding complex.F) A) and B)
G) A) and E)

Question 11

The gene regulation cascade of poxviruses is controlled by virus produced transcription factors.At what point in the virus replication cycle is the viral early transcription factor synthesized?

Accepted Answer

A)   Early
B)   Delayed Early
C)   Intermediate
D)   Late
E)   All of the above.F) D) and E)
G) A) and E)

Question 12

We no longer vaccinate people for smallpox because there are no stocks of smallpox anywhere on the planet.

Accepted Answer

A) True 
 B)False

Question 13

Which of the following cellular components is used to help extracellular virus particles of poxviruses reach and infect neighboring host cells?

Accepted Answer

A)   Export vesicles.
B)   Actin containing microvilli.
C)   Microtubules.
D)   Golgi-derived cisternae
E)   Viroplasm.F) B) and C)
G) A) and B)

Question 14

Smallpox was named in 15ᵗʰ century France to distinguish it from "large pox" or syphilis.

Accepted Answer

A) True 
 B)False

Question 15

Which of the following describes the major distinguishing feature of poxviruses when compared to other DNA containing viruses that replicate in eukaryotic cells?

Accepted Answer

A)   They encode their own DNA polymerase.
B)   They have large complex genomes that encode over 100 different proteins.
C)   They have large complex virions.
D)   They replicate exclusively in the cytoplasm of infected cells.
E)   They encode a wide-variety of regulatory proteins.F) A) and E)
G) C) and D)

Question 16

If viral DNA replication is inhibited in poxviruses, which of the following genes will not be expressed?

Accepted Answer

A)   Gene encoding the mRNA processing enzymes.
B)   Genes encoding virion structural proteins.
C)   Genes encoding DNA replication enzymes.
D)   Gene encoding the RNA polymerase subunits.
E)   Genes encoding the nucleotide metabolism enzymes.F) A) and D)
G) D) and E) B

Question 17

Describe the observations that Edward Jenner made and the experiment that he carried out to show that the "cowpox" virus could protect people from smallpox.

Accepted Answer

Edward Jenner in the late 1700's knew th...

Question 18

For most of human existence, which of the following was the approximate fatality rate from smallpox infection in the countries where it was endemic?

Accepted Answer

A)   1%
B)   10%
C)   25%
D)   50%
E)   100%F) A) and B)
G) A) and C)

Question 19

Intermediate and late gene transcription of poxviruses does NOT require any host cell proteins.

Accepted Answer

A) True 
 B)False

Question 20

Which of the following groups of organisms are the primary hosts for poxviruses?

Accepted Answer

A)   Humans
B)   Insects
C)   Plants
D)   Plants and insects.
E)   Birds, mammals and insects.F) A) and C)
G) C) and D) E

Exam 26: Poxviruses

One of the strategies used by poxviruses to inhibit host defenses involves the synthesis of a viral serpin.What is the function of the serpin?

Correct AnswerverifiedShow Answer

Which of the following describes the process of variolation, which was an early method to prevent smallpox infections?

Correct AnswerverifiedShow Answer

Poxviruses express viral proteins that interfere with all of the following host-defense systems EXCEPT:

Correct AnswerverifiedShow Answer

During infection with poxviruses, all of the following proteins are produced from early genes EXCEPT:

Correct AnswerverifiedShow Answer

Smallpox was eliminated from the human population through the use of antiviral drugs.

Correct AnswerverifiedShow Answer

Which of the following describes the structure of the vaccinia virus genome?

Correct AnswerverifiedShow Answer

If a purified poxvirus genome was heated to melt the hydrogen bonds holding the two strands of DNA together, which of the following would describe the structure of the genome?

Correct AnswerverifiedShow Answer

DNA replication in poxviruses uses a "rolling hairpin" model, similar to the method used by viruses in which of the following families?

Correct AnswerverifiedA

The mRNAs of poxviruses do not undergo splicing.Which of the following explains why?

Correct AnswerverifiedShow Answer

Intermediate and late transcripts from poxviruses have a unique "poly(A) head" near the 5' end of the mRNA.What is the proposed function for this structure?

Correct AnswerverifiedShow Answer

The gene regulation cascade of poxviruses is controlled by virus produced transcription factors.At what point in the virus replication cycle is the viral early transcription factor synthesized?

Correct AnswerverifiedShow Answer

We no longer vaccinate people for smallpox because there are no stocks of smallpox anywhere on the planet.

Correct AnswerverifiedShow Answer

Which of the following cellular components is used to help extracellular virus particles of poxviruses reach and infect neighboring host cells?

Correct AnswerverifiedShow Answer

Smallpox was named in 15ᵗʰ century France to distinguish it from "large pox" or syphilis.

Correct AnswerverifiedShow Answer

Which of the following describes the major distinguishing feature of poxviruses when compared to other DNA containing viruses that replicate in eukaryotic cells?

Correct AnswerverifiedShow Answer

If viral DNA replication is inhibited in poxviruses, which of the following genes will not be expressed?

Correct AnswerverifiedB

Describe the observations that Edward Jenner made and the experiment that he carried out to show that the "cowpox" virus could protect people from smallpox.

Correct AnswerverifiedEdward Jenner in the late 1700's knew th...View AnswerShow Answer

For most of human existence, which of the following was the approximate fatality rate from smallpox infection in the countries where it was endemic?

Correct AnswerverifiedShow Answer

Intermediate and late gene transcription of poxviruses does NOT require any host cell proteins.

Correct AnswerverifiedShow Answer

Which of the following groups of organisms are the primary hosts for poxviruses?

Correct AnswerverifiedE

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Edward Jenner in the late 1700's knew th...
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