All eukaryotic cells have within them a variety of different structures called organelles. Organelles are small and function much like organs function in a large organism. Some organelles are responsible for gathering cell energy, others for controlling cell activities.Note-although this organelle is also found animal cells, the vacuoles from plant cells are drastically bigger and play a much more important role in the processes of the cell.
HIV crossed from chimps to humans in the 1920's in what is now the Democratic Republic of Congo. This was probably as a result of chimps carrying the Simian Immunodeficiency Virus (SIV), a virus closely related to HIV, being hunted and eaten by people living in the area.
Human immunodeficiency virus (HIV) is a virus that causes the condition acquired immunodeficiency syndrome (AIDS). The virus attacks a specific type of immune system cell in the body, known as CD4 helper lymphocyte cells. HIV destroys these cells, making it harder for your body to fight off other infections. When you have HIV, even a minor infection (like a cold) can be much more severe because your body has difficulty healing. HIV is transmitted through contact with the following bodily fluids: blood ; breast milk ; semen ; vaginal fluid