Lec 2 - Virla structure

Question 1

what does the virus need to do to deliver gneome into host cell

Answer 1

bind to receptor
fuse with host cell
induce uncoating
and
exocytosis
(so struc needs to allow all of this to happen)

Question 2

why is a virus called a metastable structure

Answer 2

must be stable enough to survive outside the cell
but instable when inside the cell so it can open up and execute mechanochemical actions required for infection of other cells
(generated by non covalent bonding of protein subunits)

Question 3

what 2 types of symmetry can viruses have

Answer 3

helical
icosohderal

Question 4

example of virus w helical symm

Answer 4

tobacco mosaic virus

Question 5

structure of TMV

Answer 5

single molecule of +ssRNA
300nm long protein coat

Question 6

smallest icosohedron dimensions

Answer 6

T=1
20 triangles
60 subunits

Question 7

example of simple icosohedron

Answer 7

Parvovirus
18-26nm
causes fifth disease (slapped cheek) = mild rash in kids

Question 8

how to inc size of a virus in an icosohedral formation

Answer 8

increase triangulation value (therefore number of subunits)

Question 9

example of a T=3 virus

Answer 9

nodamura virus

Question 10

what type of glycoproteins to virus membranes usually have

Answer 10

oligomers

Question 11

example of oligomer on influenza virus

Answer 11

haemagglutinin
a trimeric glyoprotein

Question 12

what can oligeomers act as

Answer 12

cell surface receptors
antigenic determinant
mediating viral and cell membrane fusion

Question 13

example of a memb bound virus

Answer 13

measles virus (-ssRNA)
herpes simplex virus
influenza virus

Question 14

how many nucelocapsis does influenza have

Answer 14

8 seperate helical

Question 15

what does ribonuclear protein do

Answer 15

organises each RNA into a helical structure

Question 16

what do viral P proteins do

Answer 16

further fold the helical structure of RNA into litl circle