Deck 21: Viral Diversity

Question 1

Gene therapy viruses are usually constructed from which type of virus?

A) adenoviruses
B) poxviruses
C) polyomaviruses
D) cytomegaloviruses

Answer 1

A

Question 2

Viruses that infect the hyperthermophilic Archaea tend to contain genomes that are composed of

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

Answer 2

A

Question 3

Spindle- shaped viruses have been shown to infect only

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

Answer 3

C

Question 4

Influenza virus proteins are synthesized within the host's

A) cytoplasm.
B) nucleus.
C) mitochondria.
D) endoplasmic reticulum.

Question 5

Where within the host cell does coronavirus assembly occur?

A) nucleus
B) Golgi apparatus
C) endoplasmic reticulum
D) cytoplasm

Question 6

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

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

Question 7

It is estimated that viruses outnumber living cells by a factor of in the environment.

A) 10
B) 50
C) 100
D) 2

Question 8

Most bacteriophages have genomes.

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

Question 9

To cause infection, the virion Paramecium bursaria Chlorella virus 1 (PBCV- 1) must first bind to what component of the host?

A) nuclear membrane
B) cytoplasmic membrane
C) cell wall
D) endoplasmic reticulum

Question 10

Mu is a _ virus with a _ tail.

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

Question 11

In T7, the proteins that inhibit the host restriction system are synthesized

A) after the T7 genome is completely within the host cytoplasm.
B) in response to the T7 genome binding to the host chromosome.
C) before the entire T7 genome enters the cell.
D) while the T7 genome is entering the cell but before it enters the nucleus.

Question 12

Integration of Mu DNA into the host genome is essential for

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

Question 13

Which genome composition has NOT been observed in bacteriophages?

A) positive- stranded RNA
B) negative- stranded RNA
C) double- stranded RNA
D) None of the above has yet been found.

Question 14

The hepadnavirus DNA polymerase acts as which of the following?

A) a protein primer for synthesis of a strand of DNA
B) a DNA polymerase
C) a reverse transcriptase
D) All of the above are activities of the hepadnavirus DNA polymerase.

Question 15

Of the double- stranded RNA viruses, 06 seems to be very closely related to the reoviruses that infect the

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

Question 16

The filamentous DNA phages are unusual, because they

A) are released from the host without the host being lysed.
B) replicate without a host.
C) have linear genomes.
D) do all of the above.

Question 17

In bacteriophage 0X174, viral mRNA is synthesized from

A) RF DNA.
B) mRNA replicase.
C) RF RNA.
D) the host's genome.

Question 18

How many coat proteins per virion do bacteriophages have that contain RNA genomes?

A) 180
B) 30
C) 90
D) 60

Question 19

What is the primer used to synthesize DNA with a retrovirus reverse transcriptase?

A) a specific cellular tRNA
B) the VPg protein
C) an RNA primer synthesized by primase
D) a specific viral tRNA

Question 20

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

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

Question 21

Viruses that are enveloped contain _ membranes.

Question 22

The phage Mu

A) repairs mutations in the host genome.
B) has a circular genome.
C) replicates by transposition.
D) does all of the above.

Question 23

When 0X174 infects a cell, entrance of the virion into cells is accompanied by the conversion of .

Question 24

Burkitt's lymphoma, a disease common among children in Central Africa and New Guinea, is caused by the tumorigenic virus .

Question 25

The three classes of mRNA in herpesviruses are , , and .

Question 26

The is the largest virus known, contains a 1.2 Mbp dsDNA genome (twice in size of the next largest virus known), and infects in the environment.

Question 27

Transcription, replication, and encapsidation of vaccinia progeny particles occur in structures known as .

Question 28

T7 has an icosahedral head

A) and no tail.
B) and a long tail.
C) with an indeterminate tail length.
D) and a very short tail.

Question 29

What is the function of RNA replicase (RNA- dependent RNA polymerase)?

A) replicate RNA from RNA
B) replicate RNA from either DNA or RNA
C) cleave proteins and replicate RNA from RNA
D) cleave proteins

Question 30

A concatemer is a

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

Question 31

Regulation of transcription in small RNA viruses occurs primarily by .

Question 32

In 1977, Frederick Sanger and colleagues contributed to virology by being the first to
.

Question 33

Viruses often make large _ that are then cleaved into several smaller _ by proteases.

Question 34

RNA viruses can infect only enteric bacteria that contain a(n) plasmid.

Question 35

The three enzymatic activities of reverse transcriptase are activity, synthesis of DNA with a(n) template, and synthesis of DNA with a(n) template.

Question 36

A spindle- shaped virus that infects the archaeon Acidianus convivator, called ACV, is morphologically distinct from most other viruses by containing on its surface.

Question 37

Which cell- encoded protein is NOT involved in the conversion of viral ssDNA to RF DNA?

A) gyrase
B) ligase
C) reverse transcriptase
D) DNA polymerase

Question 38

In viruses the virus RNA is not the mRNA, but it is copied into mRNA by an enzyme present in the virion.

Question 39

The two proteins on the influenza virus surface are known as and .

Question 40

The terms gag, pol, and env are genes present in all .

Question 41

The herpesvirus acquires its envelope via through the of the nucleus.

Question 42

In T7 the order of the genes influences the regulation of viral multiplication.

Question 43

The nucleocapsid of vaccinia virus contains DNA surrounded by protein subunits.

Question 44

The are among the largest and most complex animal viruses known.

Question 45

Herpesviruses can remain latent in humans for several decades without causing disease by residing in the liver.

Question 46

The phenomenon of overlapping genes is more common in small viral genomes than any other grouping.

Question 47

The lipid envelope surrounding rhabdoviruses and influenza viruses is acquired from the
of the host cell.

Question 48

The polioviruses and the rhinoviruses are both classified as , because they are typically very small and contain single- stranded RNA.

Question 49

Cytomegalovirus, present in 50- 85% of adults in the United States, normally lays dormant in healthy individuals but can cause disease or even death in immune- compromised humans.

Question 50

The two kinds of coat proteins formed in the assembly of the enveloped rhabdovirus virion are _ proteins and _ proteins.

Question 51

All bacterial RNA viruses are icosahedral.

Question 52

The scientist who demonstrated that the causative agent of tobacco mosaic disease could pass through filters was _ .

Question 53

Hepadnaviruses contain DNA genomes that are partially double- stranded and partially single- stranded.

Question 54

A filamentous phage has symmetry.

Question 55

The 5,386 bp genome of 0X174 was the first DNA molecule to be completely sequenced.

Question 56

If a virus remains inactive in the host for long periods of time, it is said to be .

Question 57

Fever blisters, chickenpox, shingles, and infectious mononucleosis are all caused by
, which contain _ - stranded genomes.

Question 58

When retroviral DNA is integrated into the host genome, the integrated element is known as a(n) .

Question 59

Some viruses have been confirmed to cause cancer in humans.

Question 60

The viral DNA of simian virus 40 (SV40) codes for two DNA polymerases but must use the host for its additional polymerases.

Question 61

Explain four features that make the M13 phage useful for genetic engineering.

Question 62

The Chlorella viruses are the only source of restriction enzymes other than the prokaryotes and a few bacteriophages.

Question 63

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

Question 64

Reverse transcriptase is unique to the retroviruses.

Question 65

Viruses lack introns in their genomes.

Question 66

Explain the phenomenon of antigenic shift using the influenza virus as an example.

Question 67

Plasmodesmata have channels so narrow that the tobacco mosaic virus (TMV) cannot easily pass through; however, free RNA is able to use the channels.

Question 68

Explain why the viral genome of the MS2 phage can be immediately translated.

Question 69

The function of T7 RNA polymerase is to transcribe T7's genome and does not directly interact with any of the host's genome.

Question 70

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

Question 71

Enzymes are contained in the virion of retroviruses because the genome is not used directly as mRNA.

Question 72

Explain the relationship between rabbit myxomatosis virus and the Australian rabbit population.

Question 73

Describe the rolling circle replication mechanism for ssDNA genomes.

Question 74

Explain how vaccinia viruses are used to immunize humans against viruses other than vaccinia.

Question 75

Plant RNA viruses have specialized mechanisms to break open the thick cell walls and invade plants.

Question 76

Describe how bacteriophages in the ocean influence the bacterial populations.

Question 77

Explain the relationship between permissive cells, nonpermissive cells, and transformed cells.

Question 78

It is estimated that viruses lyse up to half of all bacterial cells in the ocean each day.

Question 79

Describe one use of bacteriophage Mu for a bacterial geneticist, and explain why it is useful.

Question 80

Despite being highly immunogenic, vaccinia viruses cause no serious health effects in humans.