Question 1

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 B)
G) A) and C) D

Question 2

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

Accepted Answer

A) True 
 B)False

Question 3

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) C) and D)
G) A) and E)

Question 4

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) B) and C)
G) B) and D)

Question 5

Vaccinia virus virions do not need any host proteins to carry out transcription and processing of the early gene mRNAs.

Accepted Answer

A) True 
 B)False

Question 6

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

Accepted Answer

A) True 
 B)False

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) C) and E)
G) A) and B)

Question 8

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 9

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) None of the above
G) A) and B)

Question 10

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 C)
G) C) and E)

Question 11

Poxviruses produced two distinct types of virions.Which of the following describes the primary role of the extracellular virus particle?

Accepted Answer

A)  They regulate the host cell antiviral defenses.
B)  They are transmitted via an insect vector.
C)  They infect new cells and tissues within a single host.
D)  They are transmitted between hosts.
E)  They can survive harsh environmental conditions.F) A) and E)
G) C) and D)

Question 12

Because poxviruses replicate exclusively in the cytoplasm of the host cell,they must encode which of the following enzymes?

Accepted Answer

A)  DNA-dependent RNA polymerase.
B)  DNA-dependent DNA polymerase.
C)  mRNA processing enzymes.
D)  Enzymes to produce deoxoynucleotides.
E)  All of the above are encoded.F) B) and D)
G) C) and D)

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) All of the above
G) A) and B)

Question 14

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) None of the above
G) C) and D)

Question 15

Vaccinia virus has been developed to express foreign proteins from bacteriophage T7 promoters.

Accepted Answer

A) True 
 B)False  True

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) B) and C)
G) C) and D)

Question 17

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-1 β\betaβ . F) C) and D)
G) A) and E) E

Question 18

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) A) and C)
G) None of the above

Question 19

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) B) and E)
G) A) and B)

Question 20

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) C) and D)
G) A) and B)

Exam 26: Poxviruses

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

Correct AnswerverifiedD

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Vaccinia virus virions do not need any host proteins to carry out transcription and processing of the early gene mRNAs.

Correct AnswerverifiedShow Answer

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

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

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

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

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 AnswerverifiedShow Answer

Poxviruses produced two distinct types of virions.Which of the following describes the primary role of the extracellular virus particle?

Correct AnswerverifiedShow Answer

Because poxviruses replicate exclusively in the cytoplasm of the host cell,they must encode which of the following enzymes?

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

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

Vaccinia virus has been developed to express foreign proteins from bacteriophage T7 promoters.

Correct AnswerverifiedTrue

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

Correct AnswerverifiedShow Answer

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 AnswerverifiedE

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

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

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

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True

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