What are viruses? Flashcards
1
Q
What are viruses?
A
- They act as obligate parasites – means they depend completely on the host for habitat and nourishment
- Also known as HOLOPARASITE
2
Q
What happens when virus enters host cell?
A
- ENTRY
- REPLICATION
- CELL DEATH
- VIRUS RELEASE
3
Q
Why do viruses need cells?
A
• They don’t have mitochondria and ribosomes – necessary for protein replication
4
Q
What is SSRNA?
A
- Positive-sense viral RNA is similar to mRNA and thus can be immediately translated by the host cell
- Negative-sense viral RNA is complementary to mRNA and thus must be converted to positive-sense RNA by an RNA polymerase before translation
5
Q
2 types of SSRNA
A
- +SSRNA - COV-2
* -SSRNA - Influenza
6
Q
+SSRNA
A
- COV-2 – uses host factors in all steps of viral infection
* Entry and replication can modulate gene expression + defences of host by co-opting HOST factors
7
Q
-SSRNA
A
• mRNA is synthesised directly from genome by RNA polymerase
