Pathogenicity of infection--> influenza I

Question 1

Which infectious diseases is the leading causes of death worldwide?

Answer 1

Respiratory tract infections

Question 2

Influenza nucleic acids?

Answer 2

ssRNA

Question 3

Influenza membrane?

Answer 3

Enveloped

Question 4

What does influenza recognise?

Answer 4

Sialic acid

Question 5

Antigenic viral components of influenza?

Answer 5

Hemagglutinin and Neuraminidase, M2 ion channel

Question 6

Why is haemagglutinin important at the first stage of replication?

Answer 6

It interacts with the surface receptors on the cells that the virus will infect

Question 7

When is neuraminidase required?

Answer 7

At the end of the replication cycle

Question 8

What is neuraminidase required for?

Answer 8

New viral particles to escape and infect other cells

Question 9

Role of M2 ion channel?

Answer 9

Helps the viral particle break apart and release the viral RNA into the cytoplasm of the infected cell
Uncoating

Question 10

What is the HA receptor?

Answer 10

Sialic acid

Question 11

Specific role of NA?

Answer 11

Cleaves sialic acid from glycoconjugates–> facilitates elution of progeny virions from infected cells

Question 12

What is sialic acid?

Answer 12

A 9 carbon chain CHO found at the end of glycoproteins on cell surface

Question 13

FIrst step of influenza replication cycle?

Answer 13

Recognition of the sialic acid cell surface receptor
Binding by HA

Question 14

What happens once HA has bound to sialic acid?

Answer 14

Fusion of the viral particle and entry of the viral particle through endocytosis

Question 15

What happens once the viral particle is in the endosome?

Answer 15

A drop in pH

Question 16

What does the M2 ion channel recognise?

Answer 16

The drop in pH in the endosome

Question 17

What happens after the M2 ion channel recognises the lower pH of the endosome?

Answer 17

Protons travel through the M2 ion channel into the nuclear capsid

Question 18

What does protons travelling out of the endosome, through the M2 ion channel, to the nuclear capsid cause?

Answer 18

Uncoating and breaking apart of the viral particle

Question 19

What does the breaking apart of the viral particle cause?

Answer 19

Release of viral RNA into the cytoplasm

Question 20

What does the viral RNA do once released?

Answer 20

Travel into the nucleus

Question 21

What happens to the viral RNA once in the nucleus?

Answer 21

Replicate viral RNA, and generate mRNA for production of new proteins

Question 22

What happens to the proteins translated from the mRNA, which was created using viral RNA?

Answer 22

They accumulate together on the surface

Question 23

What happens to the viral proteins on the surface?

Answer 23

Packaging and budding of the new viral particle

Question 24

Why do new viral particles remain attached to an infected cell?

Answer 24

They have NA which will attach to the sialic acid on the cells surface membrane

Question 25

What does the NA protein do when the viral particle remains attached after budding and release?

Answer 25

Cleaves the sialic acid receptor

Question 26

Why does NA cleave the sialic acid?

Answer 26

So the new viral particles will stop remaining attached to the cell and leave

Question 27

Components of HA?

Answer 27

Globular head and fibrous stem

Question 28

Which component of HA binds to the sialic acid receptor?

Answer 28

Globular head

Question 29

What does x-ray crystallography allow?

Answer 29

Visualisation of the 3D structure of a protein

Question 30

Which HA component attaches it to the surface of the virus?

Answer 30

fibrous stem

Question 31

What does the globular head have to let it bind to sialic acid?

Answer 31

Binding pocket that recognises the sialic acid receptor