Question

Name the type of cells the AIDS virus first enters into after getting inside the human body. Explain the sequence of events that the virus undergoes within these cells to increase their progeny.

Answer 1

HIV first enters the T-helper cells (and macrophages) after getting inside the human body.

Sequence of events within the cell

1. HIV attaches itself and binds with the plasma membrane of the T-helper cell.
2. The RNA of HIV enters the cell and uses the enzyme reverse transcriptase to make a DNA copy (cDNA) of its genetic material.
3. This single strand replicates to produce double-stranded cDNA.
4. The double-stranded viral DNA integrates into the host cell's DNA, where it directs the production of viral RNA.
5. Each strand of viral RNA directs the synthesis of viral proteins.
6. Assembly of the RNA strands and viral proteins gives rise to many new viruses.
7. These viruses are released from the host cell before it dies. The T-helper cells and macrophages thus act like an 'HIV factory'.

The newly formed HIV particles attack more T-helper cells, replicate and produce more viruses. This repeated process leads to a progressive decrease in the number of T-helper cells, weakening the immune response and ultimately leading to AIDS.