HIV

Question 1

What is HIV?

Answer 1

HIV is a virus that weakens the immune system

Question 2

What does ‘HIV’ stand for?

Answer 2

Human immunodeficiency virus

Question 3

What are the 5 components of the HIV virus?

Answer 3

• Envelope
• Attachment proteins
• Capsid
• RNA
• Reverse transcriptase (enzyme)

Question 4

What is the role of the attachment proteins?

Answer 4

They allow the virus to bind to host cells

Question 5

What is the role of reverse transcriptase?

Answer 5

Converts viral RNA into DNA

Question 6

What kind of cell does HIV use as a host cell?

Answer 6

Helper T cells

Question 7

How does HIV replicate? (6)

Answer 7

1. Attachment proteins on the surface of the virus bind to CD4 receptors on a helper T cell and the virus will fuse with the helper T cells membrane
2. The capsid of the HIV is released into the helper T cell where it uncoats and releases its RNA and enzymes
3. The enzyme reverse transcriptase copies the viral RNA into a DNA copy
4. The viral DNA is inserted into the helper T cells DNA
5. The helper T cell will make viral proteins that are used to assemble new viral particles
6. The HIV virus particles then leaves the helper T cell to infect other cells

Question 8

What does ‘AIDS’ stand for?

Answer 8

Acquired immunodeficiency syndrome

Question 9

What is the difference between HIV positive and AIDS?

Answer 9

HIV positive = when a person is infected with HIV
AIDS = when helper T cell numbers drop critically low which interferes with immune system function

Question 10

What are the 4 stages of HIV infection?

Answer 10

1 - Transmission
2 - Acute infection
3 - Latency period
4 - AIDS development

Question 11

Why are antibiotics ineffective against viruses?

Answer 11

Antibiotics only target and inhibit bacterical enzymes and ribosomes; this prevents damage to human cells
However viruses use human enzymes and ribosomes in human cells to replicate as they do not have their own