AIDS

Term paper definition suggestion: AIDS is the inability of the immune system to cope with infections and other pathological processes, and develops when the level of CD4 T lymphocyte declines below 200 cells per milliliter of blood. Normally, white blood cells and antibodies attack and destroy any foreign organism that enters the human body. This response is coordinated by one type of cells called CD4 lymphocytes. Unfortunately, HIV attacks specific cells that express the CD4 receptor, one of the most important are the CD4 + T cells and enters them. Once inside, the virus changes its genetic material from simple chain (RNA) to a double chain (DNA) for incorporation into the host's own genetic material (infected person) and uses it to replicate or make copies of itself. Then new copies of itself out of the cells get into the blood, looking for other cells to attack. Meanwhile, these cells are dying out. This cycle is repeated again and again. To defend the production of virus, the immune system produces a lot of CD4 cells daily. Gradually the number of CD4 cells decreases, so the person suffers from immunodeficiency, which means that the person can not defend themselves from other viruses, bacteria, fungi and parasites that cause disease, which leaves the person susceptible to diseases a healthy person would be able to cope, such as atypical pneumonia and meningitis atypical.

AIDS is a very popular custom essay topic. These diseases are mainly opportunistic infections. Since the body has mechanisms to control cell growth dependent on CD4 cells, the progressive destruction of these cells causes these mechanisms to be not adequately regulated, thus resulting in the presence of certain neoplasms (cancer) that do not occur in healthy people. HIV also can infect brain cells, causing some neurological disorders. Like other retroviruses, the genetic information of the virus is in the form of RNA, which contains the 'instructions' for the protein synthesis, which conform to join the new virus (virion), i.e. its heritable characteristics, which are needed to replicate. Usually, in nature DNA or deoxyribonucleic acid is a source of genetic material from which to produce a single copy of RNA, but in the case of HIV, it manages to reverse the sense of information, producing DNA from its simple RNA copies, an operation that is called reverse transcription, characteristic of retroviruses. The virus inserts its genetic information on the mechanism of replication of the cell (cell nucleus), thanks to the action of reverse transcriptase.