Question 1

Why is so much emphasis placed on the genomic composition (e.g., ssRNA, dsDNA) of individual viruses? Provide examples to support your explanation.

Accepted Answer

Answers will vary but should highlight the difference of viral genome diversity in composition compared to the three domains of life which are dominated by dsDNA genomes. Because different viruses genomes composition is so diverse, where some are positive ssRNA, negative ssRNA, dsRNA, positive ssDNA, and dsDNA, fundamental molecular mechanisms are also diverse. The genome composition often dictates which proteins must be carried and not made by the host, the type of genome replication mechanism, and the way transcripts are synthesized.

Question 2

A concatemer is a

Accepted Answer

A)  combination of two or more repeated nucleotide sequences covalently linked together. 
B)  complex of RNA-specific polymerases found only in bacteriophages. 
C)  linker molecule that allows several phages to infect one host. 
D)  polymeric protein. 
A)  combination of two or more repeated nucleotide sequences covalently linked together. 
B)  complex of RNA-specific polymerases found only in bacteriophages. 
C)  linker molecule that allows several phages to infect one host. 
D)  polymeric protein. A

Question 3

By nature of its infectivity, M13 phages can be used in the laboratory to continually propagate a particular DNA sequence inside of Escherichia coli by simply culturing infected E. coli in LB.

Accepted Answer

A) True 
 B)False  TRUE

Question 4

Reoviruses contain ________ genomes, and their replication occurs within the hostʹs ________.

Accepted Answer

A)  ssDNA / nucleus 
B)  dsDNA / nucleus 
C)  ssRNA / cytoplasm 
D)  dsRNA / cytoplasm 
A)  ssDNA / nucleus 
B)  dsDNA / nucleus 
C)  ssRNA / cytoplasm 
D)  dsRNA / cytoplasm

Question 5

Viruses are known to infect Bacteria, but no virus has yet been found that infects Archaea.

Accepted Answer

A) True 
 B)False

Question 6

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 7

Based on its function, which type(s) of viruses likely contain(s) a gene encoding for RNA replicase?

Accepted Answer

A)  dsDNA and ssDNA viruses 
B)  positive ssRNA viruses 
C)  positive and negative ssRNA viruses 
D)  ssRNA and ssDNA viruses 
A)  dsDNA and ssDNA viruses 
B)  positive ssRNA viruses 
C)  positive and negative ssRNA viruses 
D)  ssRNA and ssDNA viruses

Question 8

To date, there is no evidence that RNA viruses infect Archaea.

Accepted Answer

A) True 
 B)False

Question 9

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

Accepted Answer

A) True 
 B)False

Question 10

Integration of Mu DNA into the host genome is essential for

Accepted Answer

A)  lytic growth. 
B)  lysogenic growth. 
C)  both lytic and lysogenic growth. 
D)  neither lytic nor lysogenic growth. 
A)  lytic growth. 
B)  lysogenic growth. 
C)  both lytic and lysogenic growth. 
D)  neither lytic nor lysogenic growth.

Question 11

What is unusual about phage MS2 infection of Escherichia coli?

Accepted Answer

A)  All proteins are synthesized simultaneously during infection so there are no early and late proteins. 
B)  It attaches to the hostʹs pilus rather than the cellʹs surface. 
C)  It enters through a host cell porin. 
D)  More than one MS2 phage can be present in an individual E. coli cell. 
A)  All proteins are synthesized simultaneously during infection so there are no early and late proteins. 
B)  It attaches to the hostʹs pilus rather than the cellʹs surface. 
C)  It enters through a host cell porin. 
D)  More than one MS2 phage can be present in an individual E. coli cell.

Question 12

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

Question 13

Viruses that contain positive-strand genomes do not share genetic elements with other positive-strand genomes.

Accepted Answer

A) True 
 B)False

Question 14

The unconventional dsDNA genome replication mechanism where no lagging strand exists is a hallmark of which group of viruses?

Accepted Answer

A)  adenoviruses 
B)  coronaviruses 
C)  herpes viruses 
D)  pox viruses 
A)  adenoviruses 
B)  coronaviruses 
C)  herpes viruses 
D)  pox viruses

Question 15

Herpes viruses can cause all of the following diseases in humans EXCEPT

Accepted Answer

A)  cancer. 
B)  chicken pox. 
C)  cold sores. 
D)  spongiform encephalopathy. 
A)  cancer. 
B)  chicken pox. 
C)  cold sores. 
D)  spongiform encephalopathy.

Question 16

The Baltimore Scheme to classify viruses contains a total of ________ groups based on ________.

Accepted Answer

A)  four / genome composition 
B)  four / genome composition and transcription mechanism 
C)  seven / genome composition 
D)  seven / genome composition and transcription mechanism 
A)  four / genome composition 
B)  four / genome composition and transcription mechanism 
C)  seven / genome composition 
D)  seven / genome composition and transcription mechanism

Question 17

Identifying proteases being essential for the 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 18

Mu is a ________ virus with a ________ tail.

Accepted Answer

A)  ssRNA / filamentous 
B)  dsRNA / helical 
C)  ssDNA / filamentous 
D)  dsDNA / helical 
A)  ssRNA / filamentous 
B)  dsRNA / helical 
C)  ssDNA / filamentous 
D)  dsDNA / helical

Question 19

How do reoviruses increase the translational activity of human ribosomes so that they can rapidly produce viral proteins during infection?

Accepted Answer

A)  They chemically modify the RNA transcripts with methyl caps in a similar manner to normal eukaryotic RNA processing. 
B)  They keep a ribosome binding site specific to human ribosomes on their genome. 
C)  They have introns and sometimes extons in their genomes to make their RNA resemble eukaryotic mRNA. 
D)  They only adhere to and infect metabolically active host cells where protein synthesis is high. 
A)  They chemically modify the RNA transcripts with methyl caps in a similar manner to normal eukaryotic RNA processing. 
B)  They keep a ribosome binding site specific to human ribosomes on their genome. 
C)  They have introns and sometimes extons in their genomes to make their RNA resemble eukaryotic mRNA. 
D)  They only adhere to and infect metabolically active host cells where protein synthesis is high.

Question 20

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

Exam 10: Viral Genomics, Diversity, and Ecology

Why is so much emphasis placed on the genomic composition (e.g., ssRNA, dsDNA) of individual viruses? Provide examples to support your explanation.

A concatemer is a

By nature of its infectivity, M13 phages can be used in the laboratory to continually propagate a particular DNA sequence inside of Escherichia coli by simply culturing infected E. coli in LB.

Reoviruses contain ________ genomes, and their replication occurs within the hostʹs ________.

Viruses are known to infect Bacteria, but no virus has yet been found that infects Archaea.

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

Based on its function, which type(s) of viruses likely contain(s) a gene encoding for RNA replicase?

To date, there is no evidence that RNA viruses infect Archaea.

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

Integration of Mu DNA into the host genome is essential for

What is unusual about phage MS2 infection of Escherichia coli?

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

Viruses that contain positive-strand genomes do not share genetic elements with other positive-strand genomes.

The unconventional dsDNA genome replication mechanism where no lagging strand exists is a hallmark of which group of viruses?

Herpes viruses can cause all of the following diseases in humans EXCEPT

The Baltimore Scheme to classify viruses contains a total of ________ groups based on ________.

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

Mu is a ________ virus with a ________ tail.

How do reoviruses increase the translational activity of human ribosomes so that they can rapidly produce viral proteins during infection?

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

The Microbial World

Microbial Cell Structure and Function

Microbial Metabolism

Molecular Information Flow and Protein Processing

Microbial Growth and Its Control

Microbial Regulatory Systems

Molecular Biology of Microbial Growth

Viruses and Their Replication

Microbial Systems Biology

Genetics of Bacteria and Archaea

Biotechnology and Synthetic Biology

Microbial Evolution and Systematics

Metabolic Diversity of Microorganisms

Functional Diversity of Microorganisms

Diversity of Bacteria

Diversity of Archaea

Diversity of Microbial Eukarya

Taking the Measure of Microbial Systems

Microbial Ecosystems

Nutrient Cycles

Microbiology of the Built Environment

Microbial Symbioses

Microbial Symbioses with Humans

Microbial Infection and Pathogenesis

Innate Immunity: Broadly Specific Host Defenses

Adaptive Immunity: Highly Specific Host Defenses

Clinical Microbiology and Immunology

Epidemiology

Person-to-Person Bacterial and Viral Diseases

Vectorborne and Soilborne Bacterial and Viral Diseases

Waterborne and Foodborne Bacterial and Viral Diseases

Eukaryotic Pathogens: Fungi, Protozoans, and Helminths

Filters

Reoviruses contain genomes, and their replication occurs within the hostʹs .

The Baltimore Scheme to classify viruses contains a total of groups based on .

Mu is a virus with a tail.