Question 1

Why are ssRNA phages used as an index organism to detect the presence of pathogenic enteroviruses in the sewage treatment process?

Accepted Answer

A)  The RNA phage are smaller than the pathogenic viruses. 
B)  The RNA phage are easier to inactivate than the pathogenic viruses. 
C)  The RNA phage are more stable than the pathogenic viruses. 
D)  The RNA phage are easier to quantify using a plaque assay than the pathogenic viruses. 
E)  The RNA phage are easier to see with an electron microscope than the pathogenic viruses 
A)  The RNA phage are smaller than the pathogenic viruses. 
B)  The RNA phage are easier to inactivate than the pathogenic viruses. 
C)  The RNA phage are more stable than the pathogenic viruses. 
D)  The RNA phage are easier to quantify using a plaque assay than the pathogenic viruses. 
E)  The RNA phage are easier to see with an electron microscope than the pathogenic viruses D

Question 2

Replication of the RNA genome by the replicase enzyme from the phage Qb is completely independent of host cell proteins.

Accepted Answer

A) True 
 B)False  False

Question 3

In the ssRNA phage MS2, binding of the coat protein to which of the following RNA structures acts to initiate packaging of the viral RNA into the capsids.

Accepted Answer

A)  The 5' end of the genome 
B)  The 3' end of the genome 
C)  The MJ stem loop 
D)  The start codon of the coat protein gene 
E)  The operator stem loop 
A)  The 5' end of the genome 
B)  The 3' end of the genome 
C)  The MJ stem loop 
D)  The start codon of the coat protein gene 
E)  The operator stem loop E

Question 4

The discovery of the ssRNA phages was useful to scientists working on which of the following processes:

Accepted Answer

A)  Structure of ribosomal RNA 
B)  Translation of messenger RNA 
C)  Structure of proteins 
D)  Transcription of messenger RNA 
E)  Replication of DNA 
A)  Structure of ribosomal RNA 
B)  Translation of messenger RNA 
C)  Structure of proteins 
D)  Transcription of messenger RNA 
E)  Replication of DNA

Question 5

Site directed mutagenesis of the MS2 genome was carried out to abolish the MJ stem structure that is just upstream of the start codon of the replicase gene.Which of the following describes the result of this experiment?

Accepted Answer

A)  The coat protein was unable to bind to the viral genome. 
B)  The maturation protein was unable to bind to the stem-loop. 
C)  The ribosome could no longer bind to the start codon for the replicase gene. 
D)  The replicase protein was unable to bind to the viral genome. 
E)  Translation of replicase gene increased in the absence of coat protein translation. 
A)  The coat protein was unable to bind to the viral genome. 
B)  The maturation protein was unable to bind to the stem-loop. 
C)  The ribosome could no longer bind to the start codon for the replicase gene. 
D)  The replicase protein was unable to bind to the viral genome. 
E)  Translation of replicase gene increased in the absence of coat protein translation.

Question 6

In the ssRNA phage MS2, translation of the lysis protein gene is dependent on which of the following events?

Accepted Answer

A)  Replication of the viral genomic RNA. 
B)  Initiation of translation of the replicase gene. 
C)  Binding of the coat protein to the nucleation site on the genome. 
D)  Termination of translation of the coat protein gene. 
E)  Initiation of translation of the maturation gene. 
A)  Replication of the viral genomic RNA. 
B)  Initiation of translation of the replicase gene. 
C)  Binding of the coat protein to the nucleation site on the genome. 
D)  Termination of translation of the coat protein gene. 
E)  Initiation of translation of the maturation gene.

Question 7

Replication and translation can occur simultaneously on a single molecule of genomic RNA from the ssRNA phage MS2.

Accepted Answer

A) True 
 B)False

Question 8

The replicase enzyme of the ssRNA phage Qb has been used by scientists to do which of the following?

Accepted Answer

A)  Synthesize RNA molecules from a DNA template. 
B)  Measure small amounts of target RNA molecules in a sample. 
C)  Measure the levels of pathogenic viruses in drinking water. 
D)  Amplify DNA molecules in a sample. 
E)  Fuse two pieces of RNA together. 
A)  Synthesize RNA molecules from a DNA template. 
B)  Measure small amounts of target RNA molecules in a sample. 
C)  Measure the levels of pathogenic viruses in drinking water. 
D)  Amplify DNA molecules in a sample. 
E)  Fuse two pieces of RNA together.

Question 9

The bacteriophage MS2, which has a ssRNA genome, must produce many more copies of the coat protein than of the replicase and lysis proteins.Which of the following genome features controls how much of each protein is produced?

Accepted Answer

A)  Translational control sequences at the 3' end of the genome 
B)  Translational control sequences at the 5' end of the genome 
C)  Secondary structure of the RNA genome 
D)  The strength of the transcriptional promoters 
E)  The location of the transcriptional terminators 
A)  Translational control sequences at the 3' end of the genome 
B)  Translational control sequences at the 5' end of the genome 
C)  Secondary structure of the RNA genome 
D)  The strength of the transcriptional promoters 
E)  The location of the transcriptional terminators

Question 10

In the ssRNA phage MS2, the maturation protein is only produced after which of the following events occurs?

Accepted Answer

A)  The synthesis of the negative strand of the viral genome. 
B)  The synthesis of the positive strand of the viral genome. 
C)  Packaging of the viral genome into new capsids. 
D)  Translation of the coat protein. 
E)  Folding of the newly synthesized genome into the stable secondary structure. 
A)  The synthesis of the negative strand of the viral genome. 
B)  The synthesis of the positive strand of the viral genome. 
C)  Packaging of the viral genome into new capsids. 
D)  Translation of the coat protein. 
E)  Folding of the newly synthesized genome into the stable secondary structure.

Question 11

Which of the following structures found on E.coli cells is required for infection with a ssRNA phage?

Accepted Answer

A)  Cell wall 
B)  Lipopolysaccharide 
C)  F-pili 
D)  Cell surface receptor 
E)  All of the above are required. 
A)  Cell wall 
B)  Lipopolysaccharide 
C)  F-pili 
D)  Cell surface receptor 
E)  All of the above are required.

Question 12

During the replication cycle of the ssRNA phage MS2, the lysis gene can not be translated in the absence of translation of the coat protein gene.

Accepted Answer

A) True 
 B)False

Question 13

Which of the following proteins in the virions of the ssRNA phages binds to the F-pilus during virus attachment and entry?

Accepted Answer

A)  Lysis protein 
B)  Attachment protein 
C)  Coat protein 
D)  Maturation protein 
E)  Replicase protein 
A)  Lysis protein 
B)  Attachment protein 
C)  Coat protein 
D)  Maturation protein 
E)  Replicase protein

Question 14

When an RNA phage virion is assembled with either a defective or missing maturation protein, which of the following occurs?

Accepted Answer

A)  The viral RNA genome is more sensitive to RNAse degradation. 
B)  The virion is more sensitive to protease degradation. 
C)  The virion is unstable and disassembles easily in the environment. 
D)  The virion is not able to carry out genome replication. 
E)  The tail cannot inject the genome into the host cell. 
A)  The viral RNA genome is more sensitive to RNAse degradation. 
B)  The virion is more sensitive to protease degradation. 
C)  The virion is unstable and disassembles easily in the environment. 
D)  The virion is not able to carry out genome replication. 
E)  The tail cannot inject the genome into the host cell.

Question 15

In the ssRNA phage MS2, the replicase and lysis proteins are NOT produced immediately upon entry of the viral genome.Which of the following mechanisms is the primary explanation for why this happens?

Accepted Answer

A)  The start codons for these genes are buried in a very stable stem-loop structure. 
B)  They have Shine-Dalgarno sequences that do not bind well to the ribosome. 
C)  They both contain non-canonical TTG start codons. 
D)  The genes encoding these proteins are uncoated from the capsid until later. 
E)  The initiator tRNA does not bind well to the start codons of these genes. 
A)  The start codons for these genes are buried in a very stable stem-loop structure. 
B)  They have Shine-Dalgarno sequences that do not bind well to the ribosome. 
C)  They both contain non-canonical TTG start codons. 
D)  The genes encoding these proteins are uncoated from the capsid until later. 
E)  The initiator tRNA does not bind well to the start codons of these genes.

Question 16

Why must the ssRNA phage, like MS2 and Qb, prevent the viral genome from simultaneously being translated by a ribosome and replicated by the replicase enzyme? Describe the mechanism that these viruses use to prevent this from happening.

Accepted Answer

Ribosomes translate the RNA genome in th

Question 17

In the ssRNA phage MS2, the replicase protein binds to the start codon of the coat protein gene.Which of the following describes the reason for this binding?

Accepted Answer

A)  It prevents replication and translation from occurring simultaneously. 
B)  It initiates synthesis of the minus-strand copy of the genome. 
C)  It enhances binding of the ribosome to the coat protein gene. 
D)  It disrupts the stem-loop structure that prevents replication of the viral genome. 
E)  It exposes the 3' end of the genome which allows the replicase to begin RNA synthesis. 
A)  It prevents replication and translation from occurring simultaneously. 
B)  It initiates synthesis of the minus-strand copy of the genome. 
C)  It enhances binding of the ribosome to the coat protein gene. 
D)  It disrupts the stem-loop structure that prevents replication of the viral genome. 
E)  It exposes the 3' end of the genome which allows the replicase to begin RNA synthesis.

Question 18

The translation of the maturation protein from a newly synthesized positive strand genome in the phage MS2 depends on delayed folding of the RNA into its final secondary structure.

Accepted Answer

A) True 
 B)False

Question 19

Which of the following genes from the ssRNA phage MS2 is translated immediately upon entry of the viral genome into the host cell?

Accepted Answer

A)  Maturation protein gene 
B)  Lysis protein gene 
C)  Coat protein gene 
D)  Replicase gene 
E)  A1 gene 
A)  Maturation protein gene 
B)  Lysis protein gene 
C)  Coat protein gene 
D)  Replicase gene 
E)  A1 gene

Question 20

Once the RNA genome of Qb is released into the host cell, which of the following describes the first step in the viral replication cycle?

Accepted Answer

A)  Translation of the genome by viral ribosomes to produce proteins. 
B)  Translation of the genome by cellular ribosomes to produce proteins. 
C)  Replication of the genome by a viral enzyme. 
D)  Replication of the genome by a cellular enzyme. 
E)  Cleavage of the genome into two fragments. 
A)  Translation of the genome by viral ribosomes to produce proteins. 
B)  Translation of the genome by cellular ribosomes to produce proteins. 
C)  Replication of the genome by a viral enzyme. 
D)  Replication of the genome by a cellular enzyme. 
E)  Cleavage of the genome into two fragments.

Exam 5: Single-Stranded RNA Bacteriophages

Why are ssRNA phages used as an index organism to detect the presence of pathogenic enteroviruses in the sewage treatment process?

Replication of the RNA genome by the replicase enzyme from the phage Qb is completely independent of host cell proteins.

In the ssRNA phage MS2, binding of the coat protein to which of the following RNA structures acts to initiate packaging of the viral RNA into the capsids.

The discovery of the ssRNA phages was useful to scientists working on which of the following processes:

Site directed mutagenesis of the MS2 genome was carried out to abolish the MJ stem structure that is just upstream of the start codon of the replicase gene.Which of the following describes the result of this experiment?

In the ssRNA phage MS2, translation of the lysis protein gene is dependent on which of the following events?

Replication and translation can occur simultaneously on a single molecule of genomic RNA from the ssRNA phage MS2.

The replicase enzyme of the ssRNA phage Qb has been used by scientists to do which of the following?

The bacteriophage MS2, which has a ssRNA genome, must produce many more copies of the coat protein than of the replicase and lysis proteins.Which of the following genome features controls how much of each protein is produced?

In the ssRNA phage MS2, the maturation protein is only produced after which of the following events occurs?

Which of the following structures found on E.coli cells is required for infection with a ssRNA phage?

During the replication cycle of the ssRNA phage MS2, the lysis gene can not be translated in the absence of translation of the coat protein gene.

Which of the following proteins in the virions of the ssRNA phages binds to the F-pilus during virus attachment and entry?

When an RNA phage virion is assembled with either a defective or missing maturation protein, which of the following occurs?

In the ssRNA phage MS2, the replicase and lysis proteins are NOT produced immediately upon entry of the viral genome.Which of the following mechanisms is the primary explanation for why this happens?

Why must the ssRNA phage, like MS2 and Qb, prevent the viral genome from simultaneously being translated by a ribosome and replicated by the replicase enzyme? Describe the mechanism that these viruses use to prevent this from happening.

In the ssRNA phage MS2, the replicase protein binds to the start codon of the coat protein gene.Which of the following describes the reason for this binding?

The translation of the maturation protein from a newly synthesized positive strand genome in the phage MS2 depends on delayed folding of the RNA into its final secondary structure.

Which of the following genes from the ssRNA phage MS2 is translated immediately upon entry of the viral genome into the host cell?

Once the RNA genome of Qb is released into the host cell, which of the following describes the first step in the viral replication cycle?

Introduction to Virology

Virus Structure and Assembly

Virus Classification: The World of Viruses

Virus Entry

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