HIV

Question 2

What is a retrovirus?

Answer 2

A virus that contains the enzyme reverse transcriptase, which causes the reaction that turns viral RNA into a complementary strand of DNA.

Question 3

After infection, what is the first thing HIV does inside the body?

Answer 3

Binds to a CD4 protein on a host cell. Most typically this is a T-helper cell

Question 4

After binding to the CD4 protein, what does HIV do next?

Answer 4

The protein capsid fuses to the host cell’s cell-surface membrane and released its RNA and enzymes into the host cell

Question 5

When inside the cell, what do the RNA and enzymes do?

Answer 5

Turn the viral RNA into a complementary strand of DNA

Question 6

After the DNA is formed, where does it move to?

Answer 6

the host (T-helper) cell’s nucleus. Here it is inserted into the cell’s DNA

Question 7

Outline how HIV replicates using Th cells?

Answer 7

• HIV enters the bloodstream
• the attachment proteins on HIV bind to CD4 protein on Th cell’s cell-surface membrane
• the capsid fuses with the Th cell’s cell membrane
• the viral RNA and reverse transcriptase enter the Th cell
• HIV RNA converted into HIV DNA , using reverse transcriptase
• HIV DNA moves into nucleus and binds to Th cell DNA
• HIV mRNA is made, which contains the instructions for the formation of viral proteins (enzymes, attachment proteins, reverse transcriptase, capsid)
• new HIV particle formed
• HIV leaves the Th cell, taking some of it’s cell surface membrane with it (budding)

Question 8

Why do you wash in between steps in the ELISA test?

Answer 8

to remove any unbound antibodies, preventing false positive results