Question 1

What are the potential advantages of lysogeny compared to lysis for a temperate virus?

Accepted Answer

Answers could vary,but one idea is that lysogeny allows the virus to increase in numbers with a host without killing the host.This would be advantageous if there are few host cells present (i.e.the host population is small).Lytic viruses or lytic cycles expel viruses that then must attach to a new host to proliferate.If the viral host population is small,a lytic cycle might kill or wipe out the entire host population and prevent further viral replication.

Question 2

Whether lambda phage undergoes the lytic or lysogenic cycle is dependent on the accumulation of

Accepted Answer

A) Cro protein. 
B) viral genomes. 
C) cI protein. 
D) methylated DNA. 
A) Cro protein. 
B) viral genomes. 
C) cI protein. 
D) methylated DNA. C

Question 3

You isolate a purify a bacteriophage that can replicate in E.coli.Through chemical analyses you determine that the only nucleic acid present is RNA.You isolate the RNA and put it in a test tube with all of the necessary proteins and RNAs for translation.The RNA is translated and new infectious virions are made.What does this tell you about the bacteriophage?

Accepted Answer

A) The RNA genome is of the plus sense. 
B) The RNA genome is of the plus sense and RNA replicase is present in the viral capsid. 
C) The new bacteriophage is a retrovirus. 
D) RNA replicase is present in the viral capsid. 
A) The RNA genome is of the plus sense. 
B) The RNA genome is of the plus sense and RNA replicase is present in the viral capsid. 
C) The new bacteriophage is a retrovirus. 
D) RNA replicase is present in the viral capsid. B

Question 4

Temperate viruses can enter into either a lytic or lysogenic cycle.

Accepted Answer

A) True 
 B)False

Question 5

Compare and contrast the structure,life cycle,and host cell type of naked and enveloped viruses.

Accepted Answer

A naked virus lacks an envelope and is c

Question 6

Reverse transcriptase is a(n)

Accepted Answer

A) RNA-dependent DNA polymerase. 
B) DNA-dependent DNA polymerase. 
C) RNA-dependent RNA polymerase. 
D) DNA-dependent RNA polymerase. 
A) RNA-dependent DNA polymerase. 
B) DNA-dependent DNA polymerase. 
C) RNA-dependent RNA polymerase. 
D) DNA-dependent RNA polymerase.

Question 7

The consequence of an infection by a temperate bacteriophage is that the bacterial cell

Accepted Answer

A) lyses before it gets a chance to divide. 
B) never lyses but continues to divide and replicate both the virus and the cell. 
C) divides faster at moderate temperatures. 
D) may lyse before it divides or may continue to divide and replicate both the virus and the cell. 
A) lyses before it gets a chance to divide. 
B) never lyses but continues to divide and replicate both the virus and the cell. 
C) divides faster at moderate temperatures. 
D) may lyse before it divides or may continue to divide and replicate both the virus and the cell.

Question 8

Virions infecting some bacteria possess the enzyme ________ that makes a small hole in the bacterial cell wall,allowing the viral nucleic acid to enter.

Accepted Answer

A) peptidoglycanase 
B) infectase 
C) lysozyme 
D) nuclease 
A) peptidoglycanase 
B) infectase 
C) lysozyme 
D) nuclease

Question 9

T4 genes are transcribed by host RNA polymerase,yet the transcription of T4 genes is carefully controlled so that groups of T4 genes are transcribed at specific times after infection.How is this accomplished?

Accepted Answer

A) Early T4 genes encode for proteolytic enzymes that destroy the host RNA polymerase.Subsequently a viral polymerase is created that transcribes the middle and late genes in the correct order. 
B) Early and middle T4 genes encode for proteins that modify the activity of sigma factors and host RNA polymerase to regulate the expression of T4 genes. 
C) Each group of T4 genes has a different promoter that indicates that order in which they should be transcribed in based on the affinity of the promoter for the host RNA polymerase. 
D) Rolling circle replication of the viral genome ensures that the genes are available for transcription in the correct order. 
A) Early T4 genes encode for proteolytic enzymes that destroy the host RNA polymerase.Subsequently a viral polymerase is created that transcribes the middle and late genes in the correct order. 
B) Early and middle T4 genes encode for proteins that modify the activity of sigma factors and host RNA polymerase to regulate the expression of T4 genes. 
C) Each group of T4 genes has a different promoter that indicates that order in which they should be transcribed in based on the affinity of the promoter for the host RNA polymerase. 
D) Rolling circle replication of the viral genome ensures that the genes are available for transcription in the correct order.

Question 10

Viruses can redirect host metabolic functions.

Accepted Answer

A) True 
 B)False

Question 11

Which statement is TRUE?

Accepted Answer

A) All viruses contain their own nucleic acid polymerases. 
B) Many viruses contain their own nucleic acid polymerases. 
C) Viruses do not contain their own nucleic acid polymerases. 
D) The origins of the nucleic acid polymerases used by viruses are eukaryotic. 
A) All viruses contain their own nucleic acid polymerases. 
B) Many viruses contain their own nucleic acid polymerases. 
C) Viruses do not contain their own nucleic acid polymerases. 
D) The origins of the nucleic acid polymerases used by viruses are eukaryotic.

Question 12

Viruses variously depend on their host cell for parts of the viral replication and maturation process.Many viruses do however encode for some enzymes that facilitate certain steps or virus-specific processes for viral replication and maturation.Which cellular processes and enzymes do ALL viruses lack and must therefore ALWAYS be supplied by the host cell?

Accepted Answer

In general ALL currently described virus

Question 13

Bacteriophage have a ________ complex structure than animal viruses,because ________.

Accepted Answer

A) more / bacteriophages must be coated by lipopolysaccharide to attach to bacterial cells 
B) less / the bacteriophage does not have to penetrate the nucleus 
C) more / the bacteriophage must penetrate the peptidoglycan cell wall 
D) less / there prokaryotic cells have a simple structure compared to eukaryotic cells 
A) more / bacteriophages must be coated by lipopolysaccharide to attach to bacterial cells 
B) less / the bacteriophage does not have to penetrate the nucleus 
C) more / the bacteriophage must penetrate the peptidoglycan cell wall 
D) less / there prokaryotic cells have a simple structure compared to eukaryotic cells

Question 14

A cell that allows the complete replication cycle of a virus to take place is said to be a

Accepted Answer

A) permissive host. 
B) viral cell. 
C) dead cell. 
D) lytic cell. 
A) permissive host. 
B) viral cell. 
C) dead cell. 
D) lytic cell.

Question 15

In the first few minutes after host cell infection,the virus undergoes an eclipse.

Accepted Answer

A) True 
 B)False

Question 16

What genome composition makes viruses most susceptible to destruction by prokaryotic restriction endonucleases?

Accepted Answer

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

Question 17

Although T4 encodes over 250 proteins,it does not encode its own RNA polymerase.

Accepted Answer

A) True 
 B)False

Question 18

Bacteriophages' genomes are typically composed of

Accepted Answer

A) single-stranded RNA. 
B) single-stranded DNA. 
C) double-stranded RNA. 
D) double-stranded DNA. 
A) single-stranded RNA. 
B) single-stranded DNA. 
C) double-stranded RNA. 
D) double-stranded DNA.

Question 19

What would be the consequence of deleting the late T4 genes?

Accepted Answer

A) The T4 genome would not be copied. 
B) T4 mRNA would not be produced. 
C) T4 capsid proteins would not be made. 
D) ATP would not be produced and the T4 genome would not be packaged into the capsid. 
A) The T4 genome would not be copied. 
B) T4 mRNA would not be produced. 
C) T4 capsid proteins would not be made. 
D) ATP would not be produced and the T4 genome would not be packaged into the capsid.

Question 20

Which of the following statements is TRUE?

Accepted Answer

A) Lambda is a temperate phage that infects Escherichia coli. 
B) Lambda is a linear double-stranded DNA phage. 
C) Lambda is replicated by the rolling circle mechanism. 
D) Lambda is a temperate phage that replicates its double-stranded DNA genome with a rolling circle mechanism. 
A) Lambda is a temperate phage that infects Escherichia coli. 
B) Lambda is a linear double-stranded DNA phage. 
C) Lambda is replicated by the rolling circle mechanism. 
D) Lambda is a temperate phage that replicates its double-stranded DNA genome with a rolling circle mechanism.

Exam 8: Viruses and Virology

What are the potential advantages of lysogeny compared to lysis for a temperate virus?

Whether lambda phage undergoes the lytic or lysogenic cycle is dependent on the accumulation of

Temperate viruses can enter into either a lytic or lysogenic cycle.

Compare and contrast the structure,life cycle,and host cell type of naked and enveloped viruses.

Reverse transcriptase is a(n)

The consequence of an infection by a temperate bacteriophage is that the bacterial cell

Virions infecting some bacteria possess the enzyme ________ that makes a small hole in the bacterial cell wall,allowing the viral nucleic acid to enter.

T4 genes are transcribed by host RNA polymerase,yet the transcription of T4 genes is carefully controlled so that groups of T4 genes are transcribed at specific times after infection.How is this accomplished?

Viruses can redirect host metabolic functions.

Which statement is TRUE?

Bacteriophage have a ________ complex structure than animal viruses,because ________.

A cell that allows the complete replication cycle of a virus to take place is said to be a

In the first few minutes after host cell infection,the virus undergoes an eclipse.

What genome composition makes viruses most susceptible to destruction by prokaryotic restriction endonucleases?

Although T4 encodes over 250 proteins,it does not encode its own RNA polymerase.

Bacteriophages' genomes are typically composed of

What would be the consequence of deleting the late T4 genes?

Which of the following statements is TRUE?

Microorganisms and Microbiology

Microbial Cell Structure and Function

Microbial Metabolism

Molecular Biology

Microbial Growth and Control

Microbial Genomics

Metabolic Regulation

Viral Genomes and Diversity

Genetics of Bacteria and Archaea

Genetic Engineering and Biotechnology

Microbial Evolution and Systematics

Metabolic Diversity of Microorganisms

Functional Diversity of Bacteria

Diversity of Bacteria

Diversity of Archaea

Diversity of Eukaryotic Microorganisms

Methods in Microbial Ecology

Microbial Ecosystems

Nutrient Cycles

Microbiology of the Built Environment

Microbial Symbioses

Microbial Interactions With Humans

Immunity and Host Defense

Immune Mechanisms

Molecular Immunology

Diagnostic Microbiology

Epidemiology

Person-To-Person Bacterial and Viral Diseases

Vectorborne and Soilborne Bacterial and Viral Diseases

Water and Food As Vehicles of Bacterial Diseases

Eukaryotic Pathogens: Fungal and Parasitic Diseases

Filters

Bacteriophage have a complex structure than animal viruses,because .