L82 - Viruses General Principles 2

Question 1

Viral Receptors may be:

Answer 1

Protein (i.e. ICAM-1 for most rhinoviruses)

Carbohydrate (i.e. sialic acid for influenza)

Question 2

What are the stages of Viral Invasion:

Answer 2

1. Attachment
2. Penetration
3. Uncoating
4. Amplification
5. Assembly
6. Release

Question 3

What are 2 way penetration can occur:

Answer 3

1. Fusion at the cell membrane

2. Endocytosis

Question 4

What are the stages in Viral Replication?

Answer 4

Attachment
Penetration
uncoating
Genome Rpelciation
RNA Synthesis
Protein Synthesis
Assembly
Release
Repeat

Question 5

Where do DNA viruses replicate?

Answer 5

Nucleus

Question 6

Where do RNA viruses replicate?

Answer 6

Cytoplasm

Question 7

Budding

Answer 7

Capsid proteins and nucleic acid condense adjacent to the cell membrane.

The membrane surrounding the nucleocapsid then bulges out and becomes “nipped off” to form the new enveloped virion

Question 8

How can a virus use the Golgi Body

Answer 8

Cellular secretory pathway to exit the cell

Golgi derived vesicles are resleased to the outside of the cell when the transport vesicle fuses with the cell membrane

Question 9

What is an inclusion body

Answer 9

Accumulated viral protein at the site of virus assembly

Question 10

What are some cytopathic effects

Answer 10

Inclusion Bodies

Cell transformation

Question 11

What is cell tranformation?

Answer 11

Some viruses encode “oncogenes”.

Expresison results in tumour production.

Usually growth promoting properties, leads to uncotrolled proliferation

Question 12

Recombination vs Reassortment

Answer 12

Influenza and Rotavirus have segmented viruses and swap segments with eachother (think chromosomes)

Recombination is recombination…

Question 13

The infectious process can be halted b:

Answer 13

Neutralsing antibody

killing th einfected cell by Cyto T cells, NK, or Ab mediated mechanisms

Interferon

blocing replicaiton ccle (using antiviral drugs)