V3: HIV and AIDS

Question 1

What is the structure of the HIV virus? (6)

Answer 1

• Spherical particle
• Lipid bilayer membrane derived from host cell
• Glycoproteins
• Spherical shell of p17 proteins
• Inner conical capsule of p24 proteins
• Virus core (RNA & Reverse transcriptase)

Question 2

What is the median incubation period of HIV?

Answer 2

8-10 Years

Question 3

How does HIV bind to cells?

How does HIV fuse to the cell?

Answer 3

• HIV has proteins on its envelope that bind to the CD4+ surface receptor
• When HIV binds to a CD4+ surface receptor, it activates other proteins on the cell’s surface, allowing the HIV envelope to fuse to the outside of the cell

Question 4

Explain the retrovirus element of HIV

Answer 4

• A Viral enzyme called reverse transcriptase makes a DNA copy of the RNA.
• This new DNA is called ‘proviral DNA’

Question 5

What was the first drug license to treat HIV-1?

Answer 5

Zidovudine

Question 6

What was a disadvantage of Zidovudine?

Answer 6

High doses have marked toxic effects on bone marrow cells that necessitate transfusion in one third of patients

Question 7

How does Zidovudine work?

Answer 7

The triphosphate in the Zidovudine is a very potent inhibitor of viral RT enzyme and prevents nucleoside chain elongation

Question 8

What are the steps in HIV? (6)

Answer 8

1. Binding
2. Reverse Transcription
3. Integration
4. Transcription
5. Translation
6. Viral Assembly

Question 9

How many anti retroviral therapy medications need to used at the same time?

Answer 9

Always use 3 or more

Question 10

Anti retroviral therapy changes HIV from a fatal disease to what?

Answer 10

A chronic disease