HIV

Question 1

What cells does the HIV virus attack?

Answer 1

T(H) cells so it can make copies of itself

Question 2

What does HIV stand for?

Answer 2

Human immunodeficiency virus

Question 3

What does AIDS stand for?

Answer 3

Acquired Immune Deficiency syndrome

Question 4

What does reverse transcriptase do?

Answer 4

Catalyses the production of DNA from RNA (the opposite to transcriptase)

Question 5

What does the ability to make DNA from RNA make HIV also known as?

Answer 5

A retrovirus

Question 6

On what cell is the CD4 receptor which the HIV attaches to?

Answer 6

A T(h) cell’s surface membrane

Question 7

What type of genetic material does HIV have?

Answer 7

RNA

Question 8

What does HIV’s reverse transcriptase able it to do?

Answer 8

Insert DNA made from its RNA into the human genome

Question 9

What is the DNA spliced into the hosts DNA By?

Answer 9

An enzyme called Integrase

Question 10

What 3 viral protein types assemble together to make new viruses?

Answer 10

• Proteins, Viral RNA and Glycoproteins

Question 11

What do the new viruses take from the host cell as they “bud” out of the host cell?

Answer 11

-host lipids from the membrane to make a viral coat

Question 12

What two ways do The INFECTED Th cells get killed?

Answer 12

1) new viruses kill them as they leave
2) cytotoxic cells kill them

Question 13

When is a person said to have developed aids?

Answer 13

When their T cell count is so low that their ability to fight infection is compromised

Question 14

What does the loss of T-helper cells mean?

Answer 14

-Phagocytosis can’t occur
-So the B-cells aren’t activated so no antibodies
- so the T-killer cells kill the body cells

Question 15

Does an infected person have 200 Th cells per mm3 or lower?

Answer 15

Yes - unifected is 800-1200 per mm3

Question 16

What happens after the HIV virus enters the bloodstream and it’s proteins bind to the CD4 protein on the Th cell?

Answer 16

It’s protein capsid fuses with the cell surface membrane and the HIV RNA and enzymes enter the helper T-cell

Question 17

What happens to the new virus DNA after reverse transcriptase converts the virus RNA to DNA?

Answer 17

It is Inserted into the t-cell dna in the nucleus

Question 18

What does the mRNA created by HIV DNA and cell enzymes do?

Answer 18

It passes out of the nucleus and the T-cell now makes new HIV particles via protein synthesis

Question 19

What is left after the HIV particles break away surrounded by the T-cell surface membrane?

Answer 19

The lipid envelope on the new virus that forms