Question 1

Spindle-shaped viruses have been shown to infect only

Accepted Answer

A) Eukarya. 
B) Bacteria. 
C) Archaea. 
D) plants. 
A) Eukarya. 
B) Bacteria. 
C) Archaea. 
D) plants.

Question 2

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. 
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.

Question 3

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

Accepted Answer

A) adenoviruses 
B) cytomegaloviruses 
C) polyomaviruses 
D) poxviruses 
A) adenoviruses 
B) cytomegaloviruses 
C) polyomaviruses 
D) poxviruses

Question 4

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 5

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 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 lifestyle 
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 lifestyle

Question 7

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 8

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

Accepted Answer

A) ssDNA. 
B) dsDNA. 
C) ssRNA. 
D) dsRNA. 
A) ssDNA. 
B) dsDNA. 
C) ssRNA. 
D) dsRNA.

Question 9

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 10

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 11

Which type of viruses generally has the smallest genome?

Accepted Answer

A) bacteriophage 
B) DNA viruses 
C) RNA viruses 
D) viroids 
A) bacteriophage 
B) DNA viruses 
C) RNA viruses 
D) viroids

Question 12

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 13

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. 
A) evolutionary appearance in virus genomes. 
B) stability during infection. 
C) time of synthesis following host infection. 
D) transmission into virions.

Question 14

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 15

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. 
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.

Question 16

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

Question 17

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

Accepted Answer

A) True 
 B)False

Question 18

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

Accepted Answer

A) True 
 B)False

Question 19

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 20

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 strand 
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 strand

Exam 9: Viral Genomes and Diversity

Spindle-shaped viruses have been shown to infect only

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

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

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

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

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

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

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

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?

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

Which type of viruses generally has the smallest genome?

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?

Early and late viral proteins are classified according to their relative

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

What will happen if the Mu repressor is not synthesized?

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

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

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

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.

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

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Microbial Cell Structure and Function

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Genetics of Bacteria and Archaea

Genetic Engineering and Biotechnology

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Metabolic Diversity of Microorganisms

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Diversity of Bacteria

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Microbiology of the Built Environment

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Immunity and Host Defense

Immune Mechanisms

Molecular Immunology

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