Question 1

If the hypothesis stating viruses evolved prior to living organisms on Earth is true,the first type of viruses in the world were likely

Accepted Answer

A)  bacteriophage. 
B)  DNA viruses. 
C)  retroviruses. 
D)  RNA viruses.

Question 2

Reoviruses contain ________ genomes,and their replication occurs within the host's ________.

Accepted Answer

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

Question 3

Explain why the viral genome of the MS2 phage can be immediately translated.What type of genome must it have for this to be the case?

Accepted Answer

The answer of Explain why the viral genome of the...

Question 4

One hypothesis on the origin of DNA points to RNA viruses evolving a modified nucleotide that is insensitive to ribonucleases.

Accepted Answer

A) True 
 B)False

Question 5

Why are phylogenetic studies of viruses more challenging than Bacteria? Explain how genes are selected in viruses for phylogeny and the constraints those create.

Accepted Answer

The answer of Why are phylogenetic studies of viruses more...

Question 6

Which type of viruses can be directly used for translation?

Accepted Answer

A)  dsRNA 
B)  negative ssRNA 
C)  positive ssRNA 
D)  retroviruses

Question 7

The Baltimore classification scheme is a useful way to categorize viruses based on their host infectivity.

Accepted Answer

A) True 
 B)False

Question 8

Proteins made by a ribosome reading through a transcript's stop codon without their own discrete ribosome binding sites

Accepted Answer

A)  are thought to be a primitive mechanism to avoid host defenses. 
B)  appear most abundant in archaeal viruses and relatively uncommon in bacteriophage. 
C)  suggest a relatively low level of protein product is essential for the virus due to its rare frequency. 
D)  create opportunities for viruses to make different capsid proteins.

Question 9

Describe how bacteriophages influence the ocean's bacterial populations and nutrient cycling.

Accepted Answer

The answer of Describe how bacteriophages influence the ocean's bacterial...

Question 10

What will happen if the Mu repressor is not synthesized?

Accepted Answer

A)  Genome replication will not be able to occur. 
B)  It will lyse its host. 
C)  Mu will improperly synthesize its capsid. 
D)  Transposition will not be possible.

Question 11

By nature of its infectivity,M13 phage 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

Question 12

Viruses that contain positive-strand genomes are incompatible to share genetic elements other positive-strand genomes.

Accepted Answer

A) True 
 B)False

Question 13

Despite viruses require a living host's metabolism to replicate,it remains unclear whether viruses existed before living cells.

Accepted Answer

A) True 
 B)False

Question 14

Most archaeal viruses identified appear to have DNA genomes.

Accepted Answer

A) True 
 B)False

Question 15

The filamentous DNA phages are unusual,because they

Accepted Answer

A)  are released from the host without the host being lysed. 
B)  have linear genomes. 
C)  replicate without a host. 
D)  are released from the host without being lysed and have linear genomes.

Question 16

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 host's pilus rather than the cell's 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 17

Most known plant viruses have ________-strand RNA genomes,because small genomes ________.

Accepted Answer

A)  negative / facilitate cell-to-cell transfer 
B)  positive / facilitate cell-to-cell transfer 
C)  negative / interact more readily with host DNA 
D)  positive / interact more readily with host DNA

Question 18

Spindle-shaped viruses have been shown to infect only

Accepted Answer

A)  Eukarya. 
B)  Bacteria. 
C)  Archaea. 
D)  plants.

Question 19

Due to their indispensible role for copying its genome,an intracellular host protease that attacks the adenoviral protein ends would likely result in halting its replication.

Accepted Answer

A) True 
 B)False

Question 20

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

Exam 9: Viral Genomes and Diversity

If the hypothesis stating viruses evolved prior to living organisms on Earth is true,the first type of viruses in the world were likely

Reoviruses contain genomes,and their replication occurs within the host's .

Explain why the viral genome of the MS2 phage can be immediately translated.What type of genome must it have for this to be the case?

One hypothesis on the origin of DNA points to RNA viruses evolving a modified nucleotide that is insensitive to ribonucleases.

Why are phylogenetic studies of viruses more challenging than Bacteria? Explain how genes are selected in viruses for phylogeny and the constraints those create.

Which type of viruses can be directly used for translation?

The Baltimore classification scheme is a useful way to categorize viruses based on their host infectivity.

Proteins made by a ribosome reading through a transcript's stop codon without their own discrete ribosome binding sites

Describe how bacteriophages influence the ocean's bacterial populations and nutrient cycling.

What will happen if the Mu repressor is not synthesized?

By nature of its infectivity,M13 phage 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.

Viruses that contain positive-strand genomes are incompatible to share genetic elements other positive-strand genomes.

Despite viruses require a living host's metabolism to replicate,it remains unclear whether viruses existed before living cells.

Most archaeal viruses identified appear to have DNA genomes.

The filamentous DNA phages are unusual,because they

What is unusual about phage MS2 infection of Escherichia coli?

Most known plant viruses have -strand RNA genomes,because small genomes .

Spindle-shaped viruses have been shown to infect only

Due to their indispensible role for copying its genome,an intracellular host protease that attacks the adenoviral protein ends would likely result in halting its replication.

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