Question 1

Infective and non-infective viruses may be distinguished by growth on MacConkey's agar.

Accepted Answer

A) True 
 B)False

Question 2

The activation of the SOS system in a bacterium infected with a prophage results in

Accepted Answer

A)   destruction of the viral genes.
B)   complete lysis of the bacterial culture.
C)   mutation of the DNA.
D)   destruction of the viral repressor through host protease activity.
E)   complete lysis of the bacterial culture AND destruction of the viral repressor through host protease activity.F) A) and B)
G) A) and E)

Question 3

The receptors to which animal virus attachment proteins usually bind are

Accepted Answer

A)   proteins.
B)   carbohydrates.
C)   nucleic acid.
D)   lipids.
E)   glycoproteins.F) B) and C)
G) C) and D)

Question 4

The time from absorption to release for T-even phage is about

Accepted Answer

A)   1 minute.
B)   10 minutes.
C)   30 minutes.
D)   1 day.E) A) and C)
F) A) and D)

Question 5

Phage-encoded enzymes are

Accepted Answer

A)   all produced simultaneously.
B)   produced in a sequential manner.
C)   strictly host enzymes.
D)   used to customize the cell for viral production.
E)   produced in a sequential manner AND used to customize the cell for viral production.F) A) and E)
G) B) and E)

Question 6

The concentration of virus that infects or kills 50% of the host cells is referred to as the

Accepted Answer

A)   LD50.
B)   ID50.
C)   ID100.
D)   LD100.
E)   LD50 AND ID50.F) All of the above
G) C) and D)

Question 7

An exit method used by viruses which does not immediately destroy the host bacterium is

Accepted Answer

A)   lysis.
B)   inversion.
C)   extrusion.
D)   excising.E) B) and C)
F) None of the above

Question 8

All single-stranded DNA phages are extruded.

Accepted Answer

A) True 
 B)False

Question 9

During penetration of

Accepted Answer

A)   lysozyme is used to allow entry of the phage capsid.
B)   the tail acts as a "hypodermic needle", injecting the phage DNA into the cell.
C)   the protein fibers digest a hole in the cell wall.
D)   the bacterial receptor molecules open a hole through the cell wall.
E)   coli by the T4 phageF) A) and B)
G) C) and E)

Question 10

The structure of plant, animal and bacterial viruses are each, fundamentally, very different from one another.

Accepted Answer

A) True 
 B)False

Question 11

Specialized transduction

Accepted Answer

A)   involves the random transmission of any gene.
B)   involves the transfer of a few specific genes.
C)   utilizes a defective virus.
D)   only involves genes near the viral DNA integration site.
E)   involves the transfer of a few specific genes, utilizes a defective virus AND only involves genes near the viral DNA integration site.F) A) and B)
G) D) and E)

Question 12

The viral envelope closely resembles the

Accepted Answer

A)   prokaryotic cell wall.
B)   capsomere.
C)   eukaryotic cell membrane.
D)   cytoplasm.E) A) and B)
F) B) and C)

Question 13

Prions

Accepted Answer

A)   replicate by converting normal host proteins into prion proteins.
B)   responsible for "Mad Cow Disease" can cause a similar disease in humans.
C)   can be transmitted by consumption of dried or cooked food.
D)   that cause Spongiform Encephalopathy have the same amino acids but different folding properties from PrPc.
E)   All of the aboveF) A) and C)
G) B) and C)

Question 14

The shape of the virus is determined by its

Accepted Answer

A)   nucleic acid.
B)   capsid.
C)   envelope.
D)   tail.E) A) and B)
F) A) and C)

Question 15

If the infecting phage lacks some critical pieces of DNA necessary for replication it is called

Accepted Answer

A)   incomplete.
B)   mutated.
C)   defective.
D)   vegetative.E) A) and B)
F) All of the above

Question 16

Why is it virtually impossible to stamp out a disease caused by a zoonotic virus?

Accepted Answer

A)   You'd have to drive the vector organism extinct to do so.
B)   Many vector organisms have multiple stages of their life cycle that can carry a zoonotic virus, which complicates controlling the vector-borne transmission.
C)   Many viruses transmitted in this manner may utilize more than one vector organism.
D)   Many zoonotic viruses may be able to reside in more than 1 host organism, complicating control measures.
E)   All of the above are correct.F) A) and B)
G) A) and D)

Question 17

Outside of living cells, viruses are

Accepted Answer

A)   scavenging glucose.
B)   slowly stockpiling ATP from the mitochondria.
C)   using cilia to move to the next host.
D)   metabolically inert.E) C) and D)
F) All of the above

Question 18

The replicative form of nucleic acid in filamentous phages is

Accepted Answer

A)   dsDNA.
B)   dsRNA.
C)   positive ssRNA.
D)   negative ssDNA.E) C) and D)
F) A) and B)

Question 19

Once integrated, phage DNA can remain in the prophage state as long as

Accepted Answer

A)   the bacteria is frequently plated on new media.
B)   certain phage genes are excised.
C)   certain phage genes are repressed.
D)   bacterial repressor genes are activated.E) All of the above
F) B) and C)

Question 20

The site at which a virus has infected and subsequently lysed the infected cell, releasing its progeny to infect and lyse surrounding cells, thereby forming a "clear zone", is referred to as

Accepted Answer

A)   a burst area.
B)   a lyse area.
C)   a plaque.
D)   a dead zone.E) None of the above
F) A) and D)

Exam 13: Viruses, Viroids and Prions

The shape of the virus is determined by its

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Infective and non-infective viruses may be distinguished by growth on MacConkey's agar.

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Outside of living cells, viruses are

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During penetration of

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The concentration of virus that infects or kills 50% of the host cells is referred to as the

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The replicative form of nucleic acid in filamentous phages is

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Why is it virtually impossible to stamp out a disease caused by a zoonotic virus?

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The structure of plant, animal and bacterial viruses are each, fundamentally, very different from one another.

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Prions

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All single-stranded DNA phages are extruded.

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Specialized transduction

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The time from absorption to release for T-even phage is about

Correct AnswerverifiedShow Answer

The activation of the SOS system in a bacterium infected with a prophage results in

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Once integrated, phage DNA can remain in the prophage state as long as

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An exit method used by viruses which does not immediately destroy the host bacterium is

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The viral envelope closely resembles the

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If the infecting phage lacks some critical pieces of DNA necessary for replication it is called

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The site at which a virus has infected and subsequently lysed the infected cell, releasing its progeny to infect and lyse surrounding cells, thereby forming a "clear zone", is referred to as

Correct AnswerverifiedShow Answer

The receptors to which animal virus attachment proteins usually bind are

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Phage-encoded enzymes are

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