Question 1

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 B

Question 2

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 the 5' to 3' direction while the replicase enzyme moves in the 3' to 5' direction.If both of these processes were happening on the same genome at the same time the two complexes would meet and not be able to complete their processes.To avoid this from happening the replicase enzyme can bind to the viral RNA at two internal sites - one of which is the start site for translation of the coat protein.This is also where the ribosome binds to begin translation of the coat protein gene.This competition prevents a single genome from being replicated and translated at the same time.

Question 3

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 D

Question 4

The replicase enzyme of the ssRNA phage Q$\beta$ 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 5

Once the RNA genome of Q$\beta$ 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.

Question 6

What is the function of Host Factor during the replication of the Q$\beta$ RNA genome?

Accepted Answer

A) It delays the folding of the RNA into its final secondary structure. 
B) It makes the 3' end of the genome more accessible to the replicase enzyme. 
C) It adds a non-template A nucleotide to the 5' end of the minus strand. 
D) It facilitates binding of the replicase protein to the coat protein start codon. 
E) It prevents binding of the replicase enzyme to the 5' end of the genome. 
A) It delays the folding of the RNA into its final secondary structure. 
B) It makes the 3' end of the genome more accessible to the replicase enzyme. 
C) It adds a non-template A nucleotide to the 5' end of the minus strand. 
D) It facilitates binding of the replicase protein to the coat protein start codon. 
E) It prevents binding of the replicase enzyme to the 5' end of the genome.

Question 7

In the ssRNA phage Q$\beta$ the synthesis of the plus strand RNA genome from the negative strand template does not require the ribosomal S1 protein.Which of the following explains why?

Accepted Answer

A) The minus strand is shorter and takes less time to replicate 
B) The minus strand lacks the secondary structure that prevents replication. 
C) There is no competition between binding of the replicase enzyme and the ribosome. 
D) The replicase enzyme is more processive when copying the minus strand. 
E) The minus strand has a lower GC content than the plus strand. 
A) The minus strand is shorter and takes less time to replicate 
B) The minus strand lacks the secondary structure that prevents replication. 
C) There is no competition between binding of the replicase enzyme and the ribosome. 
D) The replicase enzyme is more processive when copying the minus strand. 
E) The minus strand has a lower GC content than the plus strand.

Question 8

Translational readthrough occasionally occurs in the coat protein gene of the ssRNA phage Q$\beta$.Which of the following describes this process?

Accepted Answer

A) The stop codon (UG
A) is read as a tryptophan codon (UGG). 
B) The RNA-dependent RNA polymerase reads into the next gene. 
C) The RNA-dependent RNA polymerase inserts an extra base in this gene. 
D) The ribosome shifts back one base and reads a different reading frame. 
E) The ribosome shifts forward one base and reads a different reading frame. 
A) The stop codon (UG
A) is read as a tryptophan codon (UGG). 
B) The RNA-dependent RNA polymerase reads into the next gene. 
C) The RNA-dependent RNA polymerase inserts an extra base in this gene. 
D) The ribosome shifts back one base and reads a different reading frame. 
E) The ribosome shifts forward one base and reads a different reading frame.

Question 9

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 10

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 11

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

Question 12

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 13

Replication of the RNA genome by the replicase enzyme from the phage Q$\beta$ is completely independent of host cell proteins.

Accepted Answer

A) True 
 B)False

Question 14

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 15

The RNA phages do not use a tail assembly to inject their genome through the cell wall of the host cell.How do they get their genome into the host cell?

Accepted Answer

The RNA phage can only infect male E.col

Question 16

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

Question 17

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 18

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 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

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.

Exam 5: Single-Stranded Rna Bacteriophages

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

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.

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

The replicase enzyme of the ssRNA phage Q β\betaβ has been used by scientists to do which of the following?

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

What is the function of Host Factor during the replication of the Q β\betaβ RNA genome?

In the ssRNA phage Q β\betaβ the synthesis of the plus strand RNA genome from the negative strand template does not require the ribosomal S1 protein.Which of the following explains why?

Translational readthrough occasionally occurs in the coat protein gene of the ssRNA phage Q β\betaβ .Which of the following describes this process?

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

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.

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

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?

Replication of the RNA genome by the replicase enzyme from the phage Q β\betaβ is completely independent of host cell proteins.

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.

The RNA phages do not use a tail assembly to inject their genome through the cell wall of the host cell.How do they get their genome into the host cell?

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 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 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?

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

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

Introduction to Virology 2

Virus Structure and Assembly

Virus Classification: the World of Viruses

Virus Entry

Microviruses

Bacteriophage

Bacteriophage Lambda

Viruses of Archaea

Cucumber Mosaic Virus

Picornaviruses

Flaviviruses

Togaviruses

Coronaviruses

Paramyxoviruses and Rhabdoviruses

Filovirouses

Bunyaviruses

Influenza Viruses

Reoviruses

Parvoviruses

Polyomaviruses

Papillomaviruses

Adenoviruses

Herpesviruses

Baculoviruses

Poxviruses

Viruses of Algae and Mimivirus

Retroviruses

Human Immunodeficiency Virus

Hepadnaviruses

Viroids and Hepatitis Delta Virus

Prions

Intrinsic Cellular Defenses Against Virus Infection

Innate and Adaptive Immune Responses to Virus Infection

Antiviral Vaccines

Antiviral Chemotherapy

Eukaryotic Virus Vectors

Filters

The replicase enzyme of the ssRNA phage Q $\beta$ has been used by scientists to do which of the following?

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

What is the function of Host Factor during the replication of the Q $\beta$ RNA genome?

In the ssRNA phage Q $\beta$ the synthesis of the plus strand RNA genome from the negative strand template does not require the ribosomal S1 protein.Which of the following explains why?

Translational readthrough occasionally occurs in the coat protein gene of the ssRNA phage Q $\beta$ .Which of the following describes this process?

Replication of the RNA genome by the replicase enzyme from the phage Q $\beta$ is completely independent of host cell proteins.