virus crap Flashcards
1
Q
virus
A
dna or rna with protein coat
2
Q
bacteriophage
A
- infect bac
- t4 has double-stranded dna in protein head
3
Q
virus structure
A
- tail that is hollow tube
- protein coat
- tail fibers that recognize sites on host
4
Q
infection
A
- virus dna is then injected thru tail fiber into host
- during infection, host makes only new particles
- immediate and delayed early genes inhibit machinery while late genes degrade host dna + code for proteins
- they do this by ID a hydroxymethyl thing
- 200 virus in 1 cell
5
Q
host defense mechanism
A
- restriction enzyme is nuclease that cleaves dna at site
- knows foreign dna
6
Q
lysogenic virus
A
- dormant (prophage: incorporates viral dna into host)
- repressor protein is expressed and binds to regulatory region
7
Q
lytic
A
- rec a protein that is made in stress time of cell
- becomes a protease and destroys the repressor protein, activates dormant virus
8
Q
rna virus
A
single standed, positive mrna
-viral rna goes to host ribosomes and makes viral proteins then rna dependent rna poly (replicase) is used to make rna again but now the — strand!
9
Q
qb phage
A
- 4 viral proteins
1) replicase
2) coat protein makes coat
3) protein that binds bac
4) protein that lyses bac - single stranded then is - strand, rna pol makes + strand
- there is no proofreading so mutations mean gain OR loss of function
10
Q
rna virus sequence
A
- usually have sequenced rna so that gene is smaller than sum of all proteins (less weight!!)
11
Q
double stranded phage
A
- and - strang
- retrovirus convert rna to dna using reverse transcriptase
- if lysogenic, then then they transform host and become oncogenic virus (cancer)
- rna goes from 5= to 3= then the dna made is from 3’ to 5’
12
Q
viroids
A
rna only, plants, no protein coat
13
Q
priods
A
misfolded proteins, cause scrapie, kuru and cj diseaser
14
Q
rous sarcoma virus
A
- 4 genes
- found in normal cells because usually there are introns
- gag: protein coat
env: glycoprotein of coat
src: needed to cause tumors (causes cancer, w/o this it is NOT oncogenic)
pol: reverse transcriptase - codes for a protein kinase that phos tyros on proteins
- important in cell growth and division regulation
15
Q
other oncogenes
A
- gtp binding proteins
- growth factor receptor
- growth factor
- dna binding
- tumor suppressor genes that stop cell growth (p53)
