Viral Structure

Question 1

What are the basic components of a viral cell?

Answer 1

Genome - in the very centre. It can be DNA/ RNA; double or single stranded; linear or circular.
Capsid protein - packages the genome to help it move from one cell to the next safely.
Some viruses will have:
Envelope - lipid bilayer acts as further protection. The matrix/ integument protein acts as a glue between the envelope and the capsid.
Surface proteins - heavily glycosylated. Work by docking the virus onto the surface of the host.

Question 2

What are the 5 basic forms of virus structure?

Answer 2

1. naked icosahedral e.g. poliovirus. Icosahedral shape with only genome and capsid.
2. naked helical e.g. tobacco mosaic (no human viruses with this structure). Only genome and capsid but in an elongated, spring like structure.
3. enveloped icosahedral e.g. herpes. Looks like the naked one but wrapped in an envelope.
4. enveloped helical e.g. measles. looks like naked helical but in a circular envelope.
5. complex e.g. poxvirus

Question 3

How do viruses help us?

Answer 3

They can be exploited for our benefit. e.g. oxford/ astra zeneca COVID-19 vaccine uses a harmless adenovirus vector to deliver the gene for COVID-19 spike protein.
Bacteriophage are also useful lab tools.
You can use relatively harmless virus to defect other viruses, and use them in gene delivery systems.
onolytic viruses can be used to treat cancer.

Question 4

What was the effect of the measles vaccine?

Answer 4

73% drop in measles deaths between 2000 and 2018.