AP BIOLOGY

Detailed explanation-1: -HIV is a virus that can cause an HIV infection if it gets into our blood stream. It then goes on to infect our immune system – the part of our body that keeps you healthy. It does this by entering T-helper cells (also called CD4 cells) so that our immune system can’t find and destroy it.

Detailed explanation-2: -HIV binds to the CD4 molecule on the surface of helper T-cells and replicates within them. This results in destruction of CD4+ T-cells and leads to a steady decline in this population of T-cells.

Detailed explanation-3: -The newly released viruses (called virions) go on to infect new CD4 cells – to repeat the process over again. The old CD4 cell then dies. This continuous process happens millions of times every day when not on ART. Without ART, HIV is one of the most active and rapidly reproducing virus.

Detailed explanation-4: -The host’s normal transcription machinery transcribes HIV DNA into multiple copies of new HIV RNA. Some of this RNA becomes the genome of a new virus, while the cell uses other copies of the RNA to make new HIV proteins.

Detailed explanation-5: -After getting into the human body, HIV first enters macrophages [0.5]. In these cells reverse transcription occurs and subsequently they are referred to as the HIV factory [1]. The next group of cells HIV attacks are the helper T-lymphocytes or TH cells. [0.5]