HIV

• read the notes on HIV below, and take the following quiz on HIV
• Human Immunodeficiency Virus
• HIV is the virus that leads to AIDS
• HIV is a retrovirus that contains RNA, and uses reverse transcriptase to copy its genome into DNA
• the viral DNA is then incorporated into the host DNA
• HIV infects Helper T lymphocytes (a type of white blood cell) which have the CD4 protein on their surface
• to a lesser extent, it also attacks any other immune cell that has the CD4 protein
• the virus contains an envelope that binds to CD4 proteins, resulting in receptor-mediated endocytosis in which the host cell engulfs the virus
• in transcribing and translating the viral genes, the host cell reproduces the virus, and it buds out of the cell to infect other cells
• the Helper T lymphocytes are disabled and destroyed, often with no symptoms, causing a significant decrease in levels of these cells
• gradual deterioration of the immune system and the destruction of the lymphoid organs triggers the immunosuppression that leads to AIDS
• Acquired Immunodeficiency Syndrome (AIDS) is the final stage of HIV infection
• one of the signs of AIDS is opportunistic infections, which take advantage of the body´s weakened immune system and lead to premature death