Ch 20 Viruses

Question 1

What is a virus?

Answer 1

noncellular particle with nucleic acids that infect a host

Question 2

Infectious RNA is a

Answer 2

Viroid

Question 3

How do viruses ensure survival?

Answer 3

Integrate themselves into host population

Question 4

True or False: Viruses are not ubiquitous

Answer 4

False

Question 5

Capsid symmetry has helical symmetry that it is which virus?

Answer 5

Filamentous virus

Question 6

Symmetrical virus with 20 identical triangular faces and 3 proteins/face is which virus?

Answer 6

Icosahedral virus

Question 7

Which kinds of viruses has multipart structures?

Answer 7

Asymmetrical viruses

Question 8

Symmetrical or Asymmetrical: T4 bacteriophages

Answer 8

Asymmetrical
icosahedral head and helical neck

Question 9

Symmetrical or Asymmetrical: Pox Viruses

Answer 9

Asymmetrical
several layers

Question 10

Tropism is
(occurs in animals)

Answer 10

Viruses ability to recognize host tissues

Question 11

How do Animal Virus Replicate : DNA virus?

Answer 11

Utilize host replication machinery

Question 12

How do Animal Virus Replicate : RNA virus?

Answer 12

Use RNA polymerase to transcribe mRNA

Question 13

How do Animal Virus Replicate : Retroviruses?

Answer 13

Use reverse transcriptase to copy their genome sequence into DNA and insert it into the host

Question 14

True or False: Viruses interact positively with hosts

Answer 14

True

Question 15

Virus niches?

Answer 15

Limit host population density, promote host diversity

Question 16

Acute v Persistent viruses

Answer 16

Acute viruses kill the host while persistent viruses do not

Question 17

True or False: Virus provide carbon balance

Answer 17

True