Smiley-3

Question 1

What must viruses do to initiate infection?

Answer 1

• attach to host cell
• uncoat genome
• deliver genome to appropriate location

Question 2

Virus-attachment proteins

Answer 2

Proteins located on outer membrane of virus used to attach to host cell receptors

Question 3

viral attachment molecules are always _____, but cell receptors can be ____, or a _____ linked to protein or lipid

Answer 3

protein, protein, or carbohydrate

Question 4

Cell receptors

Answer 4

• have normal host functions other functions besides viral entry

Question 5

Which viruses use sialic acid as their receptors?

Answer 5

Influenza, reovirus, and rotaviruses

Question 6

Why are mouse fibroblasts expressing human CD4 resistant to HIV infection?

Answer 6

They do not have the coreceptors for HIV

Question 7

Co-receptor

Answer 7

cellular chemokine receptor (normally detects chemokine)

Question 8

fibroblast

Answer 8

cell that produces collagen and extracellular matrix (for structure)

Question 9

HIV coreceptor that is implicated in human resistance to HIV

Answer 9

CCR5

Question 10

Examples of viruses that need co-receptors

Answer 10

herpes simplex virus and HIV

Question 11

Receptor for herpes virus

Answer 11

heparan sulfate of cell surface proteoglycans

Question 12

Parts of T4 bacteriophage

Answer 12

head, contractile tube, tail and tail fibers

Question 13

Where is DNA genome located in bacteriophage T4?

Answer 13

Head

Question 14

What are the protein components of “molecular machine” released by bacteriophage T4?

Answer 14

gp5 and gp27

Question 15

Function of bacteriophage molecular machine

Answer 15

• penetrate outer membrane of host cell

- has lysozyme activity to degrade peptidoglycan and allow DNA to be injected into cytoplasm

Question 16

Differences between animal cell and bacterial cell

Answer 16

animal cells have nuclei and have compartmentalized organelles

Question 17

mechanisms of entry to animal cells (x3)

Answer 17

• direct fusion of envelope with host plasma membrane
• pore-mediated penetration
• escape from endosomes

Question 18

how do viruses escape from endosomes? (x3)

Answer 18

• fusion at endosomal membrane
• lysis of endosomal membrane
• local permeabilization of endosomal membrane

Question 19

what type of viruses use direct fusion w/ host cell membrane technique?

Answer 19

enveloped

Question 20

What viruses use direct fusion w/ host cell membrane method?

Answer 20

herpesvirus retrovirus, paramyxovirus

Question 21

What type of viruses use pore-mediated penetration?

Answer 21

Non-enveloped

Question 22

Which virus use pore-mediated penetration?

Answer 22

picornaviruses

Question 23

What type of viruses use fusion at endosomal membrane?

Answer 23

enveloped

Question 24

Which virus uses fusion at endosomal membrane?

Answer 24

influenza

Question 25

What usually causes conformational change at endosome?

Answer 25

low pH

Question 26

What type of viruses use lysis of endosomal membrane?

Answer 26

non-enveloped viruses

Question 27

Which virus use lysis of endosomal membrane?

Answer 27

adenovirus

Question 28

Which virus uses local permeabilization of endosomal membrane?

Answer 28

reovirus

Question 29

MTOC

Answer 29

microtubule organizing centre

Question 30

How does herpesvirus hitchhike on MTOC?

Answer 30

capsid moves on MT to MTOC by binding to dynein motor that hydrolyzes ATP to move towards MTOC