Lec 3 - attachment and entry

Question 1

2 things that cell needs for virus to infect it

Answer 1

susceptible
And permissive

Question 2

What experiment provided the one step growth curve of bacteriophage T4

Answer 2

Ellis and Delbruck in 1939

Question 3

What was multiplicity of infection used in the experiment

Answer 3

10 phages : 1 bact

Question 4

Why did they wash and dilute the sampl

Answer 4

Synchronise infection

Question 5

What did they use to enumerate the viral particlea

Answer 5

plaque assay

Question 6

What happens during eclipse period and how long

Answer 6

Attachment, entry and uncoating

Question 7

When does curve plateau

Answer 7

at around 100 bacteriophage = average burst size

Question 8

viral cell receptor categories

Answer 8

protein
carbohydrate

Question 9

protein receptor properties

Answer 9

tissue specific
(give tissue tropism)
dictate host range

Question 10

carbohydrate receptor properties

Answer 10

less specific

Question 11

HIV and measles are examples of viruses that need WHAT to get into the cell

Answer 11

need co receptor

Question 12

name of polio recdeptor

Answer 12

CD155 or PVR

Question 13

how was PVR discovered

Answer 13

panning experiment
by transfecting mouse cells with a human cDNA library.

Question 14

1 polio virus interacts with how many receptors

Answer 14

60 receptors
VP1 at vertices forms a canyon structure,, which is where the receptor binds

Question 15

what does haemagglutinin (HAbind to

Answer 15

-vely charged terminal sialic acid
(specifially N acetyl neuraminic acid)

Question 16

what does human flu HA bind to compared to avian flu virus

Answer 16

human = a2-6 sialic acid (upper resp tract)
bird = a2-3 sialic acid
(lower resp tract)

Question 17

3 ways for virus to get into cell

Answer 17

• genome injection (naked viruses)
• membrane fusion (enveloped viruses)
• endocytosis (naked viruses OR enveloped viruses and then endosome memb fusion)

Question 18

in endocytosis, how is the virus taken in

Answer 18

via clathrin coated pit (which gets closed by dynamin)

Question 19

uncoating def

Answer 19

process of releasing the viral genomic material so that replication can take place

Question 19

diff between memb bound and naked viruses in terms of how they get their genome out

Answer 19

enveloped = fuses w endosome memb to get out
naked = lyses the endo from the inside

Question 20

where do DNA vs RNA viruses uncoat

Answer 20

DNA = nuclear pore
RNA= fuses w plasma memb or endocytic vesicle memb

Question 21

name of measles virus

Answer 21

paramyxoviridae sendai virus

Question 22

what protein on measles ccell surface allows fusion to take place

Answer 22

fusion protein F

Question 22

what receptor does measles have on it to adhere to cell surface

Answer 22

H protein

Question 23

what kind of nucleocapsid does measles have

Answer 23

ribonucleoprotein (-ssRNA and viral proteins)

Question 23

what condition is required for uncoatin gof influenza and why

Answer 23

low pH allows M2 protein ion channel to open up

Question 24

what does M2 channel allow

Answer 24

H+ to enter the virus releases the attament of the viral ribonucleoprotein which can then migrate out of the virus

Question 25

what allows the viral DNA to be imported to the nucleus in influenza

Answer 25

nuclear location signals on genome