Micro Lecture 4

Question 1

General charact. of viruses?

Answer 1

Contain DNA or RNA, protein coat, few or no enzymes for metabolism

Question 2

Virion

Answer 2

Complete, fully developed, capable of infection

Question 3

Parts of virion

Answer 3

Nucleic acid, capsid, envelope, spikes

Question 4

What is capsid composed of?

Answer 4

Capsomeres (proteins), promotes virus’ attachment to host cell

Question 5

Envelope

Answer 5

Covers capsid in some viruses, lipid/protein/carb coating

Question 6

Spikes

Answer 6

Allow viral attachment to host, means of identification, enables hemagglutination

Question 7

Name general morphology of viruses:

Answer 7

Helical: rabies, ebola
Polyhedral: adenovirus, poliovirus
Enveloped: influenza, herpes
Complex: bacteriophages, poxviruses

Question 8

What is cytopathic effect?

Answer 8

Observed deterioration of virally infected cells (normal cells grow in monolayer, transformed cells fuse), stops cell synthesis

Question 9

How are viruses identified?

Answer 9

Serological: Western blot

Nucleic acids: Restriction Fragment Length Polymorphisms, PCR

Question 10

What occurs during lytic cycle?

Answer 10

Phage causes lysis and death of host cell

Question 11

What occurs during lysogenic cycle?

Answer 11

Dormant/latent phase. Phage DNA incorporated into host DNA, specialized transduction.

Question 12

What are the results of lysogeny?

Answer 12

Immunity of lysogenic cells to reinfection by same phage.
Phage conversion.
Specialized transduction (bact. genes transferred to another bacterium via phage).

Question 13

What are stages of multiplication of animal viruses?

Answer 13

Attachment –> entry –> uncoating –> biosynthesis –> maturation –> release

Question 14

Adenoviridae

Answer 14

dsDNA, nonenveloped ***EYE INFECTIONS / VIRAL CONJUNCTIVITIS

Question 15

Poxviridae

Answer 15

dsDNA, enveloped (smallpox)

Question 16

Herpesviridae

Answer 16

dsDNA, enveloped, ***Epstein-Barr

Question 17

Papovaviridae

Answer 17

dsDNA, noneveloped, **HPV

Question 18

Hepadnaviridae

Answer 18

dsDNA, enveloped, Hep B ***uses reverse transcriptase

Question 19

Picornaviridae

Answer 19

ssRNA, + strand, nonenveloped, poliovirus

Question 20

Togaviridae

Answer 20

ssRNA, + strand, enveloped, rubella

Question 21

Rhabdoviridae

Answer 21

ssRNA, - strand, enveloped, rabies

Question 22

Reoviridae

Answer 22

dsRNA, nonenveloped, rotavirus

Question 23

Retroviridae

Answer 23

ssRNA, enveloped, HIV, ***uses reverse transcriptase

Question 24

What are oncogenes responsible for?

Answer 24

Transforming normal cells to cancer cells

Question 25

What is in transformed cell?

Answer 25

TSTA- tumor specific transplant antigen on surface or T antigen in nucleus

Question 26

What are some cytopathic effects?

Answer 26

Stops cell synthesis Loss of contact inhibition (transformation) Interferons (alpha, beta) to protect uninfected cells Antigenic changes on cell surface

Question 27

What is a fusing of cells?

Answer 27

Synctium

Question 28

What are interferons? What are the 3 types?

Answer 28

Cytokines produced by lymphocytes and macrophages; are antiviral. IFN alpha/beta cause cells to make antiviral proteins. IFN gamma cause neutrophils/macrophages to kill bact.

Question 29

Give an example of cell-mediated immunity.

Answer 29

Cytotoxic T-lymphocyte: kills self-cells altered by infection

Question 30

What are 3 things a vaccine does?

Answer 30

- primary immune response - antibodies and memory cells - rapid, intense secondary response

Question 31

What are antimicrobial biocides effective against?

Answer 31

Lipid-soluble, enveloped host viruses

Question 32

What do entry and fusion inhibitor antivirals do?

Answer 32

Block receptors on host cell that bind to virus / block fusion of virus and cell

Question 33

What do nucleic acid inhibitor antivirals do?

Answer 33

Analogs inhibit DNA/RNA synthesis

Question 34

What do protease inhibitor antivirals do?

Answer 34

Block cleavage of protein precursors

Question 35

What do exit inhibitor antivirals do?

Answer 35

Inhibit enzyme required for virus to bud from host. ***Tamiflu

Question 36

Define antiretroviral

Answer 36

RNA, requires reverse transcriptase

Question 37

What are viroids?

Answer 37

Short pieces of naked DNA

Question 38

What is a virion?

Answer 38

A complete infectious particle