FoM:L2 -Viral structure and function Flashcards
1
Q
Outline the basic life cycle of a virus
A
- attachment
- penetration
- uncoating
- gene expression and replication
- assembly
- release
2
Q
What is the virion?
A
- virus particle
- transports and protects the viral genome
- binds to uninfected cell
3
Q
What is a non-enveloped virus?
A
- no lipid envelope
- only icosahedral
- better at withstanding tougher environments
4
Q
What is an enveloped virus?
A
- lipid bilayer surrounds capsid
- contain envelope proteins that can bind to cells (fusion)
5
Q
What structural proteins are associated with a virion?
A
- capsid - made up from capsomeres
- envelope proteins
- tegument/matrix proteins
6
Q
What non-structural proteins are associated with virions?
A
- need proteins to be able to replicate when inside host
- viral polymerase
7
Q
What are the 3 major groups as classified by Baltimore classification? Give 1 example of each
A
- DNA viruses (Herpes)
- RNA viruses (Rotaviruses)
- Reverse-transcribing viruses/Retroviruses (HIV)
8
Q
How do DNA viruses replicate?
A
- need DNA polymerase to replicate genome (use their own or from host cell)
- DNA is transcribed and translated to form proteins
9
Q
How do +ve strand RNA viruses replicate?
A
- use their genome as a mRNA for protein production
10
Q
How do -ve strand RNA viruses replicate?
A
- transcribe mRNAs from their genome
- need their own enzymes
11
Q
How do retroviruses replicate?
A
- contain reverse transcriptase, changes RNA to viral DNA
- viral DNA integrates
- host cell proteins synthesise viral proteins and genomes
12
Q
What is latency?
A
- viruses can express none or a limited number of viral proteins
- so are undetected in cells and can be reactivated
