HIV and AIDS

Question 1

what is HIV

Answer 1

human immunodeficiency virus which is transmitted by direct transfer of bodily fluids

Question 2

what is a retrovirus

Answer 2

a virus that contains RNA instead of DNA in its capsid, e.g HIV

Question 3

life cycle of HIV

Answer 3

1. viral gp120 receptors bind to CD4 receptors on T-helper cells
2. viral lipid envelop fuses with host csm
3. viral RNA and proteins enter the host cell
4. RNA is then reverse transcribed to cDNA using viral protein reverse transcriptase
5. the viral cDNA is then integrated into host cells DNA using viral enzyme intergrase
6. viral DNA is now transcribed and translated by host cell
7. this produces viral RNA and proteins which are assembled into viral particles
8. these viral particles then become enclosed in the host cells membrane creating the viruses lipid envelope
9. the host cell is eventually killed

Question 4

stages from HIV to AIDS

Answer 4

1. acute phase
   - fevers, sweats, headaches, swollen lymph node
   - rapid viral replication and loss of T-helper cells
2. chronic phase
   - no symptoms but increased risk of colds
   - dormant diseases such as TB can be reactivated
3. disease phase
   - increasing viral load and decreasing T-helper cell numbers
   - low T-helper cell numbers result in increased risk of opportunistic infections which can be fatal

Question 5

antiretroviral drugs

Answer 5

1. entry inhibitor
   - stops the HIV glycoprotein from binding to CD4 receptor so virus cannot enter a host cell
2. reverse transcriptase inhibitor
   - stops viral HIV RNA from being converted to DNA
3. intergrase inhibitor
   - viral DNA can not be incorporated into host DNA