HIV

Question 1

Describe how HIV is replicated once inside helper T cells

Answer 1

RNA is converted into DNA using reverse transcriptase
DNA is inserted into helper T cell nucleus
DNA is transcribed into HIV mRNA
HIV mRNA is translated into new HIV/viral proteins

Question 2

Do viruses have a cell wall?

Answer 2

No- so cant be destroyed by antibiotics

Question 3

What is the HIV core made out of?

Answer 3

Genetic matieral (RNA) and the enzyme reverse transcriptase- needed for viral replication

Question 4

What is the capsid?

Answer 4

The outer protein coat

Question 5

What is the envelope made out of?

Answer 5

The host cell membrane
(Lipid membrane)

Question 6

What are the protein attachments?

Answer 6

On the exterior of the envelope to enable the virus to attach to the hosts helper T cell

Question 7

What is AIDS?

Answer 7

Where the replicating viruses in the helper T cells interfere with the T cells normal functioning of the immune system
The helper T cells are being destroyed by the virus so the host is unable to produce an adequate immune response to other pathogens- left vulnerable to infections and cancer- this destruction of the immune system leads to death

Question 8

What is HIV?

Answer 8

Virus that affects the immune system

Question 9

What does HIV do?

Answer 9

Infects and kills helper T cells which acts as the host cells for the virus
People develop AIDS when the helper T cells numbers i the body reach a critically low level

Question 10

AIDS symptoms?

Answer 10

Initial symptoms- minor infections and recurring respiratory infections
As AIDS progresses, the number of immune system cells decrease further- serious infections e.g. diarrhoea

Question 11

HIV replication?

Answer 11

Attachment proteins attach to CD4 receptors on T helper cells.
HIV fuses with cell surface membrane and viral RNA enters the T helper cells
Reverse transcriptase converts viral RNA into DNA
DNA is inserted into the T helper cell’s DNA/nucleus via the enzyme integrase
DNA is transcribed into HIV mRNA, producing viral proteins
HIV mRNA is translated into HIV for assembly and are released from the T helper cells, causing the T helper cell to burst.