HIV

Question 1

What is the structure of HIV?

Answer 1

• core: contains genetic material (RNA) and reverse transcriptase (needed for viral replication)
• capsid: outer protein coat
• envelope: extra outer layer, made out of membrane taken from the host’s cell membrane
• attachment protein: on the exterior of the envelope; enables virus to attach to the host’s t helper cells

Question 2

Where does HIV replication take place?

Answer 2

t helper cells

Question 3

Describe the process of HIV replication.

Answer 3

1. HIV is transported around the blood until it attaches to a protein on the t-helper cells
2. HIV protein capsule fuses with the t-helper cell membrane, enabling RNA and enzymes to enter
3. Reverse transcriptase copies the viral RNA (which has been injected) into a DNA copy and moves into the t helper cell nucleus
4. There, mRNA is transcribed, the t helper cell starts to create viral proteins to make new viral particles

Question 4

What is the difference between being HIV positive and having AIDS?

Answer 4

• HIV positive: person infected with HIV
• AIDS: replicating viruses in t helper cells interfere with their normal functioning of the immune system

Question 5

Describe AIDS.

Answer 5

• because the virus destroys the t helper cells, the host can’t produce an adequate immune response to other pathogens and is left vulnerable to infections and cancer.
• destruction of the immune system leads to death, not HIV directly