Immunity Flashcards
1
Q
how does HIV replicate once inside helper T cells
A
- RNA is converted into DNA by reverse transcription
- DNA is then inserted into the genome
- the host cell then transcribes it into mRNA
- it is then translated into viral proteins in the ribosomes
2
Q
what does immunodefiency mean
A
decrease or weaken the bodys ability to fight of infections
3
Q
give 3 ways which HIV can be transmitted
A
- unproctected sex
- mother to child during pregnancy
- transfusion with HIV infected blood
4
Q
what is intergrase
A
an enzyme which can insert viral DNA into host cell DNA
5
Q
how does HIV cause AIDS
A
- HIV attacks the immune system by destroying CD4 positive T helper cells
- this leaves people vulnerable
- over time HIV levels increase in the blood
6
Q
what are the 3 roles of T helper cells
A
- activate B cells to secrete antibodies
- activate macrophages
- activate cytotoxic T cells
7
Q
what are macrophages
A
a type of WBC which surrounds and kills organisms and removes dead cells
8
Q
why do antibiotics not work against HIV
A
- bacteria have murein cell walls
- viruses reproduce inside host cells. antibiotics cannot reach these cells
9
Q
how does a phagocyte destory a pathogen in the blood
A
- the phagocyte englufs the pathogen
- the vesicles in a phagocyte contain lysosomes which has lysozymes
- lysosomes fuse to the pathogen whilst lysozymes hydrolyse it
10
Q
give two types of cell other than pathogens which can stimulate an immune response
A
- foreign cells
- cancerous cells
11
Q
what is the role of a disulfide bridge in forming the quartenry structure
A
they join the polypeptide chains together
