A Fact sheet specifically tailored for OCR AS Biology, however can be suitably applied to Edexcel and AQA specifications. This fact sheet focuses on HIV / AIDS. More fact sheets can be found on my channel.

1. HIV/AIDS FACT
SHEET
HI Virus
The human immunodeficiency virus is not cellular - it is a ball of
protein and lipid around a core containing RNA and the enzyme
‘reverse transcriptase’ which is required once the virus is inside the
cell.
What Is HIV/AIDS?
HIV/AIDS is a virus which invades the cells and takes over the genetic machinery and other organelles
of the cells. It is caused by the human immunodeficiency virus.
The virus could enter the body and remain inactive, which is known as being HIV positive.
Once the virus becomes active, it attacks and destroys the Th (T-Helper) cells in the immune cells. The
Th cells help prevent infection. Once these are destroyed, the bodies ability to resist infection is
drastically reduced. A range of opportunist infections could occur which could eventually kill a person
with HIV because you cannot fight the disease.
Transmission Of HIV
1) Exchange of bodily fluids
2) Blood to blood contact
3) Unprotected sexual intercourse
4) Shared hypodermic needles
5) Unscreened blood transfusions
6) Unsterilised surgical equipment
7) Accidents such as needle-sick
8) Across the placenta
9) During childbirth
10) Whilst breast feeding.
HIV - AIDS Confusion
AIDS (acquired
immunodeficiency
syndrome) is caused by HIV
(human immunodeficiency
virus).
HIV is a retrovirus which
contains RNA instead of
DNA.
• Enzyme produces DNA version of RNA
• Infected cell follows the code on the DNA
• Makes new viruses
• HIV can only reproduce inside a host cell
• HIV infects T-Lymphocytes.
AIDS
Most people who are infected with the human immunodeficiency
virus go on to develop acquired immunodeficiency syndrome.
At first the virus lies low, undetected in the T-lymphocytes.
The person may have no symptoms but when the virus is active
and kills the T-Cells, AIDS sets in where opportunistic infections
occur.