5.7: Human immunodeficiency virus (HIV)

Question 1

What does HIV cause

Answer 1

AIDS

Question 2

What is the basic structure of HIV

Answer 2

Lipid Envelope

Attachment proteins that are embedded in the envelope

A protein layer inside the envelope called the Capsid

RNA and enzymes that are enclosed by the Capsid

Reverse Transcriptase - catalyses the production of DNA from RNA

Question 3

What group of viruses does HIV belong to

Answer 3

Retroviruses

Question 4

By being a virus what does it mean HIV cant do and has to do as a result

Answer 4

HIV cannot replicate itself so it has to use its genetic material to instruct a host cell to produce the components required for new HIV

Question 5

How does HIV replicate itself (Process)

Answer 5

1. Following infection, HIV enters the blood stream and circulates around the body
2. An attachment protein on the HIV readily binds to a protein called CD4, this is most often on a helper T cell
3. The protein capsid of the HIV fuses with the cell-surface membrane. The RNA and enzymes of HIV enter the Helper-T cell
4. The HIV reverse transcriptase converts the viruses RNA into DNA
5. The newly made DNA enters the host cells nucleus where it is inserted into the cells DNA
6. The HIV DNA in the nucleus creates mRNA. This contains the instructions to make new HIV
7. mRNA passes out of the nucleus through a nuclear pore and uses the cells protein synthesis mechanisms to make HIV particles
8. HIV particles break way from the helper T cell with a piece of its cell-surface membrane surrounding them forming its lipid envelope