Lec 5 - Exocytosis and genome recognition

Question 1

what phase in one step growth curve does exocytosis happen

Answer 1

rise period
each virus has avg burst size

Question 2

how to naked viruses leave cell

Answer 2

once cpasid is made = cell lysis

Question 3

how do memb bound viruses leave the cell

Answer 3

need to acquire memb
then leave via budding (maybe secondary cell lysis will occur)

Question 4

what do bacteriophage release to get out of cell

Answer 4

cytolytic molecules
remember - peptidoglycan cell wall more robust than eukaryotic, so cell lysis needs to happen for it to leave

Question 5

name the primer on poilio that allows RNA replication

Answer 5

VPG

Question 6

what does polio P1 encode for

Answer 6

capsid subunits
V1 V2 etc

Question 7

what does polio P2 encode for

Answer 7

protease 2A and toxin 2A

Question 8

what does polio P3 encode for

Answer 8

replicase
VPG
protease

Question 9

what does 5’ end of mRNA in cell have that allows ribosomes to recognise

Answer 9

eIF4F complex

Question 10

how does polio stop the cells protein synthesis

Answer 10

cleaves eIF4F complex with its 2A protease
means cellular RNA cant bind ribosomes

Question 11

how does polio ensure that the cellular ribosomes can recognise its RNA

Answer 11

has IRES sequence in its genome

Question 12

which polio protein alter membrane permeability of host

Answer 12

2B toxin

Question 13

how does influenza virus acquire its membrane

Answer 13

cell’s plasma memb

Question 14

how does herpes virus acquire its membrane

Answer 14

internal membranes of secretory pathway

Question 15

what protein does coronavirus use to acquire its secretory membranes

Answer 15

E1
lots deposited in ER

Question 16

herpes virus: protein used to get nucleocapsid out of nucleus

Answer 16

UL34
UL31
these 2 catalyse budding
and tegument proteins

Question 17

herpes virus: which proteins allow uptake of NC into golgi

Answer 17

gE gI and gM
tegument proteins will bind to these and its taken into golgi

Question 18

what needs to be cleaved in HIV to make it infectious

Answer 18

Gag polyprotein
(cleaved by HIV protease - used as drug target)

Question 19

what do viruses have that allows it to distinguish viral genomes from cellular gneomes

Answer 19

packaging signals

Question 20

packaging signal in SV40

Answer 20

sp1

Question 21

packaging signal in herpes virus

Answer 21

pac1 and pac2

Question 22

what is a concatemer

Answer 22

long strand of DNA, lots of copies of the viral genome

Question 23

influenza has a segmented genome (8 segments) - how does it ensure capsid interacts with correct genomes

Answer 23

each segment has unique packaging signal
so its not random (which what was originally thought)