Question 1

Viruses that infect the hyperthermophilic Archaea tend to contain genomes that are composed of

Accepted Answer

A)  ssDNA.
B)  dsDNA.
C)  ssRNA.
D)  dsRNA.E) A) and B)
F) None of the above

Question 2

Describe one use of bacteriophage Mu for a bacterial geneticist,and explain why it is useful.

Accepted Answer

Answers will vary,but bacteriophage Mu i...

Question 3

Is there a certain type of virus morphology that is especially known to cause disease in humans? Explain your reasoning.

Accepted Answer

No,there is not a particular morphology ...

Question 4

Why are phylogenetic studies of viruses more challenging than Bacteria? Explain how genes are selected in viruses for phylogeny and the constraints those create.

Accepted Answer

Viruses lack ribosomal RNA gene sequence...

Question 5

Spindle-shaped viruses have been shown to infect only

Accepted Answer

A)  Eukarya.
B)  Bacteria.
C)  Archaea.
D)  plants.E) C) and D)
F) A) and D)

Question 6

Which feature,if changed,would NOT abolish M13's utility as a cloning vector?

Accepted Answer

A)  ssDNA genome becoming a dsDNA genome
B)  loss of genes that make coat proteins
C)  replacing the segment of non-coding DNA in its genome with an indispensible gene
D)  switch from lysogenic to lytic lifestyleE) A) and C)
F) A) and B)

Question 7

Which type of viruses generally has the smallest genome?

Accepted Answer

A)  bacteriophage
B)  DNA viruses
C)  RNA viruses
D)  viroidsE) B) and D)
F) A) and C)

Question 8

Varied transcription mechanisms distinguish the different DNA virus Baltimore classes,whereas varied translational mechanisms distinguish RNA viruses.

Accepted Answer

A) True 
 B)False

Question 9

Due to the genetic diversity of viruses and their lack of ribosomal RNA,nucleotide-based phylogeny studies are not applicable to virology.

Accepted Answer

A) True 
 B)False

Question 10

Describe the hypothesis of viruses occurring before living cells and how DNA might have evolved.What is the current hypothesis about the evolutionary relationships between RNA,DNA,viruses,and cellular life?

Accepted Answer

One hypothesis on the origin of viruses ...

Question 11

What will happen if the Mu repressor is not synthesized?

Accepted Answer

A)  Genome replication will not be able to occur.
B)  It will lyse its host.
C)  Mu will improperly synthesize its capsid.
D)  Transposition will not be possible.E) None of the above
F) A) and B)

Question 12

One hypothesis on the origin of DNA points to RNA viruses evolving a modified nucleotide that is insensitive to ribonucleases.

Accepted Answer

A) True 
 B)False

Question 13

Identifying proteases being essential for replication of a virus would suggest the virus

Accepted Answer

A)  lyses its host following genome replication.
B)  contains at least one polyprotein.
C)  has a single-stranded RNA genome.
D)  uses at least one set of overlapping genes.E) B) and C)
F) None of the above

Question 14

Gene therapy viruses are usually constructed from which type of virus?

Accepted Answer

A)  adenoviruses
B)  cytomegaloviruses
C)  polyomaviruses
D)  poxvirusesE) None of the above
F) B) and C)

Question 15

Unusually shaped viruses,such as lemon-shaped and spindle-shaped,have recently been discovered in

Accepted Answer

A)  Archaea.
B)  Bacteria.
C)  Archaea and Bacteria.
D)  Eukarya.E) C) and D)
F) B) and C)

Question 16

Early and late viral proteins are classified according to their relative

Accepted Answer

A)  evolutionary appearance in virus genomes.
B)  stability during infection.
C)  time of synthesis following host infection.
D)  transmission into virions.E) All of the above
F) B) and C)

Question 17

What is the purpose of synthesizing a negative strand RNA in positive stranded ssRNA viruses?

Accepted Answer

A)  enable rolling circle amplification of the genome,which requires both strands of RNA
B)  enable transcription of genes occurring on both the negative and positive strands of the genome,such as overlapping genes
C)  proofreading of the genome to minimize mutations generated by the polymerase being passed onto virion progeny
D)  to serve as the complementary template sequence in genome amplification of the positive strandE) B) and D)
F) A) and D)

Question 18

Due to their indispensible role for copying its genome,an intracellular host protease that attacks the adenoviral protein ends would likely result in halting its replication.

Accepted Answer

A) True 
 B)False

Question 19

Explain why the viral genome of the MS2 phage can be immediately translated.What type of genome must it have for this to be the case?

Accepted Answer

The MS2 phage has a positive ssRNA genom...

Question 20

Some virus shapes that infect members of Archaea are unique from other viruses that infect eukaryotes and bacteria.

Accepted Answer

A) True 
 B)False

Exam 9: Viral Genomes and Diversity

Explain why the viral genome of the MS2 phage can be immediately translated.What type of genome must it have for this to be the case?

Correct AnswerverifiedThe MS2 phage has a positive ssRNA genom...View AnswerShow Answer

Due to the genetic diversity of viruses and their lack of ribosomal RNA,nucleotide-based phylogeny studies are not applicable to virology.

Correct AnswerverifiedShow Answer

Describe one use of bacteriophage Mu for a bacterial geneticist,and explain why it is useful.

Correct AnswerverifiedAnswers will vary,but bacteriophage Mu i...View AnswerShow Answer

What is the purpose of synthesizing a negative strand RNA in positive stranded ssRNA viruses?

Correct AnswerverifiedShow Answer

Identifying proteases being essential for replication of a virus would suggest the virus

Correct AnswerverifiedShow Answer

Some virus shapes that infect members of Archaea are unique from other viruses that infect eukaryotes and bacteria.

Correct AnswerverifiedShow Answer

Which type of viruses generally has the smallest genome?

Correct AnswerverifiedShow Answer

Early and late viral proteins are classified according to their relative

Correct AnswerverifiedShow Answer

Due to their indispensible role for copying its genome,an intracellular host protease that attacks the adenoviral protein ends would likely result in halting its replication.

Correct AnswerverifiedShow Answer

Describe the hypothesis of viruses occurring before living cells and how DNA might have evolved.What is the current hypothesis about the evolutionary relationships between RNA,DNA,viruses,and cellular life?

Correct AnswerverifiedOne hypothesis on the origin of viruses ...View AnswerShow Answer

Which feature,if changed,would NOT abolish M13's utility as a cloning vector?

Correct AnswerverifiedShow Answer

What will happen if the Mu repressor is not synthesized?

Correct AnswerverifiedShow Answer

Why are phylogenetic studies of viruses more challenging than Bacteria? Explain how genes are selected in viruses for phylogeny and the constraints those create.

Correct AnswerverifiedViruses lack ribosomal RNA gene sequence...View AnswerShow Answer

One hypothesis on the origin of DNA points to RNA viruses evolving a modified nucleotide that is insensitive to ribonucleases.

Correct AnswerverifiedShow Answer

Is there a certain type of virus morphology that is especially known to cause disease in humans? Explain your reasoning.

Correct AnswerverifiedNo,there is not a particular morphology ...View AnswerShow Answer

Viruses that infect the hyperthermophilic Archaea tend to contain genomes that are composed of

Correct AnswerverifiedShow Answer

Unusually shaped viruses,such as lemon-shaped and spindle-shaped,have recently been discovered in

Correct AnswerverifiedShow Answer

Spindle-shaped viruses have been shown to infect only

Correct AnswerverifiedShow Answer

Varied transcription mechanisms distinguish the different DNA virus Baltimore classes,whereas varied translational mechanisms distinguish RNA viruses.

Correct AnswerverifiedShow Answer

Gene therapy viruses are usually constructed from which type of virus?

Correct AnswerverifiedShow Answer

Correct Answer
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The MS2 phage has a positive ssRNA genom...
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Correct Answer
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Answers will vary,but bacteriophage Mu i...
View Answer

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Correct Answer
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Correct Answer
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One hypothesis on the origin of viruses ...
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Correct Answer
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Viruses lack ribosomal RNA gene sequence...
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No,there is not a particular morphology ...
View Answer

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