0311 - Virology - EG

Question 1

What are viruses?

Answer 1

Obligate parasites with not metabolic processes (no mitochondria, ER, Golgi); have either DNA or RNA genome that is linear or circular and doubles stranded or single stranded, contained in a capsid which is either non-enveloped or enveloped.

Question 2

What is the difference between +’ve sense and -‘ve sense ssRNA?

Answer 2

+‘ve sense is ready to be translated by ribosomes, -‘ve sense needs to be converted to +’ve sense before it can be translated.

Question 3

List the basic steps of virus replication.

Answer 3

1. attachment
2. entry/penetration
3. uncoating/viral gene expression
4. virus genome replication
5. assembly of new virions
6. exit/release/virus shedding

Question 4

List some outcomes for the host cell due to virus infection

Answer 4

• transformation to tumour cell
• cell death
• latent infected cell

Question 5

What is tropism?

Answer 5

the favoured site of virus replication, i.e.

• cellular
• primary tissue or organ
• secondary tissue or organ

Question 6

What factors affect the outcomes in individuals?

Answer 6

• dose
• host genetics
• host age
• immune status
• route of exposure