Test 3 Viruses

Question 1

What is a virus?

Answer 1

A sub-microscopic, obligate intracellular parasite.

Question 2

What are two components of EVERY virus?

Answer 2

Nucleic acid and capsid

Question 3

The nucleic acid of a virus can be…

Answer 3

DNA or RNA, and double-stranded or single-stranded

Question 4

Capsid is

Answer 4

The outer protein cover of a virus that protects the genetic material.

Question 5

Viral envelope is

Answer 5

1.A structure in some viruses that is composed of lipids and proteins that derive from the host’s cell membrane or internal membrane;
2. It helps a virus recognize and enter host cells.

Question 6

Spike is

Answer 6

1. A protein embedded in the viral envelope
2. Which assists in recognition and attachment to the host cell.

Question 7

What is the plaque assay technique

Answer 7

A method of virus quantification that involves placing viruses on a bacterial colony and counting the plaques, or areas where the viruses have killed cells.

Question 8

What is Positive-sense RNA (+RNA)

Answer 8

RNA that can be directly translated into viral proteins.

Question 9

What is negative-sense RNA (-RNA)

Answer 9

1. RNA that is complementary to the viral mRNA
2. Has to be used to create a positive-sense strand by RNA polymerase prior to translation

Question 10

What are naked viruses?

Answer 10

VIruses that lack a viral envelope

Question 11

What is mucosal immunity?

Answer 11

Immunity derived from mechanisms that stop the virus from infecting the body through a mucous membrane.

Question 12

What is apoptosis

Answer 12

Programmed cell death

Question 13

What is a retrovirus?

Answer 13

1. A virus that replicates by converting its single-stranded RNA genome to double-stranded DNA
2. Integrating it into the host cell’s genome.

Question 14

What is reverse transcriptase (RT)

Answer 14

An enzyme that facilitates the creation of DNA from an RNA trancript.

Question 14

What is intergrase

Answer 14

An enzyme that assists in the integration of DNA into a chromosome.

Question 15

What is the most common route of entry for all viral diseases?

Answer 15

The respiratory tract

Question 16

What are Alveolar macrophages?

Answer 16

Immune cells that fight infection in the alveoli.

Question 17

What are Neurotropic viruses

Answer 17

Viruses that spread through cells in the nervous system.

Question 18

What are Lymphotropic viruses

Answer 18

Viruses that spread through the lymphatic system.

Question 19

When does viremia occur?

Answer 19

Occurs when viruses are present in the bloodstream.

Question 20

What is a lytic infection

Answer 20

(Also sometimes called a permissive infection or a productive infection.)
1. A type of viral infection in which the virus infects the hosts
2. Uses the hosts cellular machinery to make more copies of itself,
3. Kills the host.

Question 21

What is persistent infection

Answer 21

1. A type of viral infection in which the viruses reproduce slowly and don’t immediately kill the host
2. Rather, they cause the slow production of more viruses over a long period of time.

Question 22

What is transforming infection?

Answer 22

A type of viral infection in which the viruses causes a mutation in the host’s chromosome

Question 23

What is a latent infection?

Answer 23

1. A type of viral infection in which the viral genome is integrated into the host’s genome, where it remains without killing the host.
2. If it is integrated into the host genome, it becomes a provirus.

Question 24

Cold sores are often produced as the result of a(n) ________________ viral infection

Answer 24

latent

Question 25

What are cyopathic effects?

Answer 25

The observable effects of a viral infection that can be visualized with a microscope

Question 26

What is a viral plaque

Answer 26

A visible area where a virus has destroyed infected cells in a cell culture.

Question 27

What is syncytia?

Answer 27

A combination of multiple cells into a single cell with multiple nuclei.

Question 28

What is the one-step growth cycle?

Answer 28

1. Describes the pattern of observed viral proliferation in an infected cell
2. No viruses are detectable during the eclipse period.
3. It is not until the yield (or rise) period that viruses become detectable.

Question 29

What is the eclipse period?

Answer 29

The period during the one-step growth cycle of a virus during which viruses are not detectable

Question 30

What triggers the uncoating of a virus and fusion of the virus with an endosome?

Answer 30

A low pH

Question 31

What is syndrome?

Answer 31

A collection of signs and symptoms

Question 32

What is induction

Answer 32

The process in which an environmental cue causes the prophage to begin synthesizing new phage particles.

Question 33

What is the temperate phage?

Answer 33

1. A phage that is capable of establishing lysogeny
2. Integrating into bacterial host.