Lecture 6, 7 and 8

Question 1

What are the 7 different genome types?

Answer 1

1. linear, circular, segmented, gapped
2. Single stranded (+/-), ambisense
3. double stranded
4. DNA or RNA
5. DNA with short segments of RNA
6. DNA or RNA with covalently attached proteins

Question 2

How are different types of genome prepared to be ready for mRNA?

Answer 2

+ssRNA- direct template for mRNA
-ssRNA-must be copied into +sense stand first
dsRNA- must be copied into mRNA using - strand template
ssDNA- must be replicated into dsDNA using the hosts’ polymerase.

Question 3

What are the requirements for successful viral infection?

Answer 3

1. Sufficient viral particles must be available.
2. The cells at the primary site of infection must be accessible, susceptible and permissive.
3. The local host antiviral defences must be absent or initially defective.