Question 1

Viral replication occurs

Accepted Answer

A)   intracellularly.
B)   extracellularly.
C)   both intracellularly and extracellularly.
D)   either intracellularly or extracellularly, depending on the virus involved.E) B) and D)
F) B) and C)

Question 2

The use of ________ is the easiest and most effective way of studying many animal and plant viruses.

Accepted Answer

A)   bacterial cultures
B)   tissue or cell culture
C)   live hosts
D)   prophagesE) B) and D)
F) B) and C)

Question 3

Penetration requires that the entire virus is inserted within the host.

Accepted Answer

A) True 
 B)False

Question 4

Rolling circle replication of the lambda genome differs from replication of a bacterial chromosome in that

Accepted Answer

A)   bidirectional replication forks are not formed.
B)   only a single strand of the genome is copied.
C)   no concatamers are formed.
D)   only a single strand of the genome is copied and no concatamers are formed.E) A) and D)
F) A) and C)

Question 5

Ocean and lake water typically contain 10⁷ virions/mL.Does this mean that swimming in or drinking this water will make you sick? Why or why not? How do these viruses impact human and environmental health?

Accepted Answer

Although there are many virions per mL o...

Question 6

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.E) B) and C)
F) A) and D) B

Question 7

Viruses have both an intracellular and an extracellular form.

Accepted Answer

A) True 
 B)False

Question 8

In a natural population of diverse slow-growing prokaryotic cells,what type of viruses would you expect to be most common?

Accepted Answer

A)   lytic bacteriophages
B)   enveloped viruses
C)   icosahedral viruses
D)   temperate bacteriophagesE) A) and B)
F) None of the above

Question 9

Explain why some viruses contain enzymes within the virion and others do not.Use specific examples to support your answer.

Accepted Answer

In the example of retroviruses,the rever...

Question 10

In viruses,genetic information flows from ________ to ________.

Accepted Answer

A)   RNA / virion
B)   nucleic acid / protein
C)   capsid / virion
D)   DNA / proteinE) All of the above
F) A) and D)

Question 11

RNA viruses encode host restriction systems designed to destroy host DNA.

Accepted Answer

A) True 
 B)False

Question 12

Viruses can confer additional properties on their host cells,which can in turn be inherited.

Accepted Answer

A) True 
 B)False

Question 13

You are attempting to mutate lambda to affect whether lysis or lysogeny occurs after lambda infection.Which mutation would INCREASE the chances of LYSOGENY over lysis?

Accepted Answer

A)   deletion or inactivation of the cI gene
B)   deletion or inactivation of the cro gene
C)   overexpression of the cro gene
D)   deletion of both the cro and cI genesE) C) and D)
F) None of the above

Question 14

Tailed bacterial viruses can be used as genetic engineering tools.

Accepted Answer

A) True 
 B)False

Question 15

The virus repressor protein provides immunity to infection by the same type of virus.

Accepted Answer

A) True 
 B)False

Question 16

The latent phase in the viral growth curve and the lag phase of the bacterial growth curve are equivalent and represent the time it takes for the virus or bacterium to adapt to the culture conditions and begin growing.

Accepted Answer

A) True 
 B)False

Question 17

Lysogeny is unique to bacteriophages; similar relationships have not been found among the animal viruses.

Accepted Answer

A) True 
 B)False

Question 18

Describe the establishment and maintenance of the lysogenic state in the lambda phage.

Accepted Answer

Lambda phage,once circularized by matchi...

Question 19

The growth of viruses in a culture is described as a one-step growth curve,because

Accepted Answer

A)   virion numbers show no increase during intracellular replication and can only be counted after the virions burst from the host cell.
B)   there is only one step in the viral life cycle which leads to only one replicative cycle in a culture.
C)   assembly and release actually occur in one step.
D)   the eclipse phase prevents the plating and enumeration of virions although new virions are produced at a steady rate during the eclipse phase.E) A) and C)
F) B) and D) A

Question 20

Relate the structure of bacteriophages and animal viruses to the structure of their respective host cells and the steps of the viral life cycle.

Accepted Answer

The T4 phage has a very complex structure,containing a head,collar,tail,tail pins,an endplate,and tail fibers.The tail fibers bind to specific receptors on the surface of a bacterial cell (outside the peptidoglycan cell wall).When the tail fibers retract,the tail pins bind to the host so that the tail itself interacts with the cell wall.A viral enzyme then forms a small pore in the host cell wall.The tail's covering then contracts and inserts the virus into the host's cytoplasm.Animal viruses are usually much simpler in structure than bacteriophages because animal host cells lack a cell wall.Penetration is therefore somewhat easier and is usually accomplished by endocytosis or merging of the viral envelope with the host cell membrane.The complicated fibers and contractile tail are not needed to penetrate the animal cell.One last difference is that the entire virion often enters the animal cell and not just the viral genome.

Exam 8: Viruses and Virology

Viral replication occurs

Correct Answer
verified

The use of ________ is the easiest and most effective way of studying many animal and plant viruses.

Correct Answer
verified

Penetration requires that the entire virus is inserted within the host.

Correct Answer
verified

Rolling circle replication of the lambda genome differs from replication of a bacterial chromosome in that

Correct Answer
verified

Ocean and lake water typically contain 10⁷ virions/mL.Does this mean that swimming in or drinking this water will make you sick? Why or why not? How do these viruses impact human and environmental health?

Correct Answer
verified
Although there are many virions per mL o...
View Answer

Which statement is TRUE?

Correct Answer
verified
B

Viruses have both an intracellular and an extracellular form.

Correct Answer
verified

In a natural population of diverse slow-growing prokaryotic cells,what type of viruses would you expect to be most common?

Correct Answer
verified

Explain why some viruses contain enzymes within the virion and others do not.Use specific examples to support your answer.

Correct Answer
verified
In the example of retroviruses,the rever...
View Answer

In viruses,genetic information flows from to .

Correct Answer
verified

RNA viruses encode host restriction systems designed to destroy host DNA.

Correct Answer
verified

Viruses can confer additional properties on their host cells,which can in turn be inherited.

Correct Answer
verified

You are attempting to mutate lambda to affect whether lysis or lysogeny occurs after lambda infection.Which mutation would INCREASE the chances of LYSOGENY over lysis?

Correct Answer
verified

Tailed bacterial viruses can be used as genetic engineering tools.

Correct Answer
verified

The virus repressor protein provides immunity to infection by the same type of virus.

Correct Answer
verified

The latent phase in the viral growth curve and the lag phase of the bacterial growth curve are equivalent and represent the time it takes for the virus or bacterium to adapt to the culture conditions and begin growing.

Correct Answer
verified

Lysogeny is unique to bacteriophages; similar relationships have not been found among the animal viruses.

Correct Answer
verified

Describe the establishment and maintenance of the lysogenic state in the lambda phage.

Correct Answer
verified
Lambda phage,once circularized by matchi...
View Answer

The growth of viruses in a culture is described as a one-step growth curve,because

Correct Answer
verified
A

Relate the structure of bacteriophages and animal viruses to the structure of their respective host cells and the steps of the viral life cycle.

Exam 8: Viruses and Virology

Viral replication occurs

Correct AnswerverifiedShow Answer

The use of ________ is the easiest and most effective way of studying many animal and plant viruses.

Correct AnswerverifiedShow Answer

Penetration requires that the entire virus is inserted within the host.

Correct AnswerverifiedShow Answer

Rolling circle replication of the lambda genome differs from replication of a bacterial chromosome in that

Correct AnswerverifiedShow Answer

Ocean and lake water typically contain 10⁷ virions/mL.Does this mean that swimming in or drinking this water will make you sick? Why or why not? How do these viruses impact human and environmental health?

Correct AnswerverifiedAlthough there are many virions per mL o...View AnswerShow Answer

Which statement is TRUE?

Correct AnswerverifiedB

Viruses have both an intracellular and an extracellular form.

Correct AnswerverifiedShow Answer

In a natural population of diverse slow-growing prokaryotic cells,what type of viruses would you expect to be most common?

Correct AnswerverifiedShow Answer

Explain why some viruses contain enzymes within the virion and others do not.Use specific examples to support your answer.

Correct AnswerverifiedIn the example of retroviruses,the rever...View AnswerShow Answer

In viruses,genetic information flows from ________ to ________.

Correct AnswerverifiedShow Answer

RNA viruses encode host restriction systems designed to destroy host DNA.

Correct AnswerverifiedShow Answer

Viruses can confer additional properties on their host cells,which can in turn be inherited.

Correct AnswerverifiedShow Answer

You are attempting to mutate lambda to affect whether lysis or lysogeny occurs after lambda infection.Which mutation would INCREASE the chances of LYSOGENY over lysis?

Correct AnswerverifiedShow Answer

Tailed bacterial viruses can be used as genetic engineering tools.

Correct AnswerverifiedShow Answer

The virus repressor protein provides immunity to infection by the same type of virus.

Correct AnswerverifiedShow Answer

The latent phase in the viral growth curve and the lag phase of the bacterial growth curve are equivalent and represent the time it takes for the virus or bacterium to adapt to the culture conditions and begin growing.

Correct AnswerverifiedShow Answer

Lysogeny is unique to bacteriophages; similar relationships have not been found among the animal viruses.

Correct AnswerverifiedShow Answer

Describe the establishment and maintenance of the lysogenic state in the lambda phage.

Correct AnswerverifiedLambda phage,once circularized by matchi...View AnswerShow Answer

The growth of viruses in a culture is described as a one-step growth curve,because

Correct AnswerverifiedA

Relate the structure of bacteriophages and animal viruses to the structure of their respective host cells and the steps of the viral life cycle.

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
Although there are many virions per mL o...
View Answer

Correct Answer
verified
B

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
In the example of retroviruses,the rever...
View Answer

In viruses,genetic information flows from to .

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
Lambda phage,once circularized by matchi...
View Answer

Correct Answer
verified
A