Question 1

The advantage of using a helical instead of an icosahedral nucleocapsid to package a ssRNA genome is…..

Accepted Answer

A)   it is more efficient to envelope a helical nucleocapsid than an icosahedral capsid.
B)   it is easier to produce a helical nucleocapsid than an icosahedral capsid.
C)   it better protects the genome from degradation inside the cell.
D)   it requires a smaller protein to build than an icosahedral capsid.
E)   it requires fewer copies of the nucleocapsid protein than an icosahedral capsid.F) C) and D)
G) None of the above

Question 2

According to the RNA World hypothesis, which of the following enzymes may have evolved first?

Accepted Answer

A)   DNA-dependent RNA polymerase
B)   DNA-dependent DNA polymerase
C)   RNA-dependent RNA polymerase
D)   RNA-dependent DNA polymerase
E)   self-replicating RNAsF) D) and E)
G) C) and D)

Question 3

Which of the following virus families have the ability to synthesize reverse transcriptase?

Accepted Answer

A)   Retroviruses
B)   Caulimoviruses
C)   Hepadnaviruses
D)   None of the above are correct.
E)   All of the above are correct.F) A) and B)
G) None of the above

Question 4

Which of the following characteristics are NOT one of the most important criterion used to classify viruses into families?

Accepted Answer

A)   topology of genome (linear or circular) 
B)   strandedness of genome (double or single stranded) 
C)   type of nucleic acid used in genome (DNA or RN
A)  
D)   structure of virion
E)   species of host infectedF) A) and B)
G) A) and C)

Question 5

Which of the following types of genomes is most commonly found in viruses that can infect fungi?

Accepted Answer

A)   ssDNA
B)   dsDNA
C)   ssRNA
D)   dsRNA
E)   All of the above are found.F) A) and E)
G) C) and E)

Question 6

Mimivirus, which infects an amoeba, is the largest known dsDNA virus and has a genome larger than some free living bacteria and archae.Even though it encodes many of its own enzymes and even tRNAs, it still does not produce its own ribosomes.Describe the possible evolutionary origin of such a large and complex viruses.

Accepted Answer

Mimiviruses, along with poxviruses, are ...

Question 7

Why is the type of disease caused not the best criteria to use when classifying a virus?

Accepted Answer

The disease caused by a specific virus i...

Question 8

What is approximately the largest size of a double-stranded DNA genome of a virus that infect vertebrates?

Accepted Answer

A)   25 kbp.
B)   50 kbp
C)   100 kbp
D)   300 kbp
E)   500 kbpF) A) and B)
G) B) and D) D

Question 9

There are a number of small DNA viruses that are highly dependent on their host cells for transcription and replication enzymes.Which of the following could explain the evolutionary origins of these viruses?

Accepted Answer

A)   They originated from fragments of the genomes of larger more independent viruses.
B)   They originated from intracellular plasmids found in bacteria.
C)   They originated from the genomes of intracellular organelles, such as mitochondria.
D)   They originated from fragments of cellular DNA that broke away from the cell genome.
E)   All of the above could be correct.F) A) and B)
G) B) and D) D

Question 10

Retroviruses are the only virus family known to package two copies of its genome.

Accepted Answer

A) True 
 B)False  True

Question 11

Almost all of the viruses with positive-strand RNA genomes and enveloped virions infect which group of hosts?

Accepted Answer

A)   Bacteria.
B)   Vertebrates
C)   Plants
D)   Fungi
E)   Algae.F) D) and E)
G) A) and C)

Question 12

What distinguishes a satellite virus from a satellite nucleic acid?

Accepted Answer

A)   A satellite virus encodes its own capsid protein while a satellite nucleic acid does not.
B)   A satellite virus packages its own replication protein while a satellite nucleic acid does not.
C)   A satellite virus requires a helper virus while a satellite nucleic acid does not.
D)   Genomes of satellite viruses are smaller than those of satellite nucleic acids.
E)   Satellite viruses do not encode any proteins while satellite nucleic acids do.F) B) and D)
G) D) and E)

Question 13

According to the RNA World hypothesis, which of the following subcellular entities may have evolved first?

Accepted Answer

A)   Retroviruses
B)   RNA Viruses
C)   Viroids
D)   DNA Viruses
E)   BacteriophagesF) A) and B)
G) B) and E)

Question 14

The family classification scheme for DNA bacteriophages is not very useful for describing the evolutionary relationships between these viruses.What is the best explanation for this?

Accepted Answer

A)   DNA bacteriophages can infect more than one host species.
B)   DNA bacteriophages have a wide variety of virion structures.
C)   The viral genomes are genetic mosaics due to recombination.
D)   There are too many bacteriophages to classify into families.
E)   These viruses do not have an evolutionary relationship to each other.F) C) and D)
G) None of the above

Question 15

Most viruses that infect plants have the following type of genome?

Accepted Answer

A)   ssDNA, positive sense
B)   ssDNA, negative sense
C)   ssRNA, positive sense
D)   ssRNA, negative sense
E)   None of the above.F) All of the above
G) A) and D)

Question 16

Viroids do not require a helper virus in order to replicate and cause disease.

Accepted Answer

A) True 
 B)False

Question 17

There are several types of viruses with enveloped virions that can infect plants.

Accepted Answer

A) True 
 B)False

Question 18

Which of the following may be a factor in explaining why viral ssRNA genomes are not usually as long as the dsDNA genomes?

Accepted Answer

A)   It is much more difficult to package a large ssRNA genome into a capsid.
B)   Long ssRNA molecules form too many secondary structures that inhibit replication.
C)   Long RNA genomes are difficult to translate.
D)   Long RNA genomes are difficult to transcribe.
E)   Long pieces of RNA are easily broken by mechanical damage.F) A) and B)
G) A) and C)

Question 19

Which of the following virus families contains viruses with the longest ssRNA genomes?

Accepted Answer

A)   Picornaviruses
B)   Coronaviruses
C)   Flaviviruses
D)   Togaviruses
E)   BromovirusesF) A) and B)
G) A) and C)

Question 20

What is a possible explanation for why ssDNA viruses have genomes less that 10kb in size?

Accepted Answer

A)   ssDNA is not as physically stable as dsDNA.
B)   ssDNA is not transcribed by host cells.
C)   ssDNA can form hairpin structures because of base-pairing.
D)   Larger pieces of ssDNA can not be replicated.
E)   Larger pieces of ssDNA can not easily enter the host cell.F) B) and D)
G) B) and C)

Exam 3: Virus Classification: The World of Viruses

The advantage of using a helical instead of an icosahedral nucleocapsid to package a ssRNA genome is…..

Correct Answer
verified

According to the RNA World hypothesis, which of the following enzymes may have evolved first?

Correct Answer
verified

Which of the following virus families have the ability to synthesize reverse transcriptase?

Correct Answer
verified

Which of the following characteristics are NOT one of the most important criterion used to classify viruses into families?

Correct Answer
verified

Which of the following types of genomes is most commonly found in viruses that can infect fungi?

Correct Answer
verified

Correct Answer
verified
Mimiviruses, along with poxviruses, are ...
View Answer

Why is the type of disease caused not the best criteria to use when classifying a virus?

Correct Answer
verified
The disease caused by a specific virus i...
View Answer

What is approximately the largest size of a double-stranded DNA genome of a virus that infect vertebrates?

Correct Answer
verified
D

There are a number of small DNA viruses that are highly dependent on their host cells for transcription and replication enzymes.Which of the following could explain the evolutionary origins of these viruses?

Correct Answer
verified
D

Retroviruses are the only virus family known to package two copies of its genome.

Correct Answer
verified
True

Almost all of the viruses with positive-strand RNA genomes and enveloped virions infect which group of hosts?

Correct Answer
verified

What distinguishes a satellite virus from a satellite nucleic acid?

Correct Answer
verified

According to the RNA World hypothesis, which of the following subcellular entities may have evolved first?

Correct Answer
verified

The family classification scheme for DNA bacteriophages is not very useful for describing the evolutionary relationships between these viruses.What is the best explanation for this?

Correct Answer
verified

Most viruses that infect plants have the following type of genome?

Correct Answer
verified

Viroids do not require a helper virus in order to replicate and cause disease.

Correct Answer
verified

There are several types of viruses with enveloped virions that can infect plants.

Correct Answer
verified

Which of the following may be a factor in explaining why viral ssRNA genomes are not usually as long as the dsDNA genomes?

Correct Answer
verified

Which of the following virus families contains viruses with the longest ssRNA genomes?

Correct Answer
verified

What is a possible explanation for why ssDNA viruses have genomes less that 10kb in size?

Correct Answer
verified

Exam 3: Virus Classification: The World of Viruses

The advantage of using a helical instead of an icosahedral nucleocapsid to package a ssRNA genome is…..

Correct AnswerverifiedShow Answer

According to the RNA World hypothesis, which of the following enzymes may have evolved first?

Correct AnswerverifiedShow Answer

Which of the following virus families have the ability to synthesize reverse transcriptase?

Correct AnswerverifiedShow Answer

Which of the following characteristics are NOT one of the most important criterion used to classify viruses into families?

Correct AnswerverifiedShow Answer

Which of the following types of genomes is most commonly found in viruses that can infect fungi?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedMimiviruses, along with poxviruses, are ...View AnswerShow Answer

Why is the type of disease caused not the best criteria to use when classifying a virus?

Correct AnswerverifiedThe disease caused by a specific virus i...View AnswerShow Answer

What is approximately the largest size of a double-stranded DNA genome of a virus that infect vertebrates?

Correct AnswerverifiedD

There are a number of small DNA viruses that are highly dependent on their host cells for transcription and replication enzymes.Which of the following could explain the evolutionary origins of these viruses?

Correct AnswerverifiedD

Retroviruses are the only virus family known to package two copies of its genome.

Correct AnswerverifiedTrue

Almost all of the viruses with positive-strand RNA genomes and enveloped virions infect which group of hosts?

Correct AnswerverifiedShow Answer

What distinguishes a satellite virus from a satellite nucleic acid?

Correct AnswerverifiedShow Answer

According to the RNA World hypothesis, which of the following subcellular entities may have evolved first?

Correct AnswerverifiedShow Answer

The family classification scheme for DNA bacteriophages is not very useful for describing the evolutionary relationships between these viruses.What is the best explanation for this?

Correct AnswerverifiedShow Answer

Most viruses that infect plants have the following type of genome?

Correct AnswerverifiedShow Answer

Viroids do not require a helper virus in order to replicate and cause disease.

Correct AnswerverifiedShow Answer

There are several types of viruses with enveloped virions that can infect plants.

Correct AnswerverifiedShow Answer

Which of the following may be a factor in explaining why viral ssRNA genomes are not usually as long as the dsDNA genomes?

Correct AnswerverifiedShow Answer

Which of the following virus families contains viruses with the longest ssRNA genomes?

Correct AnswerverifiedShow Answer

What is a possible explanation for why ssDNA viruses have genomes less that 10kb in size?

Correct AnswerverifiedShow Answer

Correct Answer
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Mimiviruses, along with poxviruses, are ...
View Answer

Correct Answer
verified
The disease caused by a specific virus i...
View Answer

Correct Answer
verified
D

Correct Answer
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D

Correct Answer
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True

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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