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Apoptosis: Difference between revisions
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Apoptosis, programmed cell death, is hot issue to biologist and scientists. It occurs in multicellular organisms with active process. Apoptosis occurs by cell shrinkage, protein fragmentation, chromatin condensation, DNA degradation and collapse of cell. [http://www.nature.com/nature/insights/6805.html] | |||
Cell dies two different ways: apoptosis and necrosis. Apoptosis and necrosis could be similar, but they are very different. Apoptosis is controlled process for number of cells, but necrosis is dying cells by swelling and bursting. Unlikely necrosis, apoptosis is integral process. Body weight is balanced, body, body shape, separating digits, and making right neuronal connections occur by apoptosis. [http://www.scq.ubc.ca/?p=350] | |||
Apoptosis has two pathways: extrinsic and intrinsic. Extrinsic pathway delivers apoptotic message, and intrinsic pathway transmits death signals. [http://www.apoptosisworld.com/] | |||
Since 1990s, research on apoptosis becomes hot issue. Apoptosis is defective process, so it might bring cancer, ischemic damage, and cell-lose disease. Usually 50 billion to 70 billion cells die each day. [http://en.wikipedia.org/wiki/Apoptosis] | |||
Labeling nuclear DNA fragmentation and gel electrophoresis are methods to identify apoptosis.[http://www.esi-topics.com/apoptosis/] | |||
==Development== | |||
Origin of apoptosis is Greek. In Greek, apoptosis means falling off. Apoptosis is very necessary part of life cycle of organisms. Apoptosis is active process and plays important role in multicellular organisms. It regulates and adjusts population of cells. [http://www.celldeath.de/encyclo/aporev/aporev.htm] | |||
Programmed cell death, Apoptosis, is necessary process in both animal tissue and plants tissue developments. The cells grow and produces other cells, but also, they cell are dying. The cells’ death could occur by Apoptosis or cell injuries. Dead cells are used by other cells. | |||
Different tissues use different signals for apoptosis. BMP, bone morphogenetic proteins, induces apoptosis in interdigital tissue which is in birds. [http://en.wikipedia.org/wiki/Apoptosis] | |||
==Process== | |||
Cell signals control process of apoptosis. The cell signals are extracellular or intracellular. | |||
Hormones, growth factors, nitric oxicers, and cytokines are extracellular signals, and they cross plasma membranes. Intercellular signals are cell stress, cell suicide, heat, radiation, nutrient deprivation, and viral infection. [http://en.wikipedia.org/wiki/Apoptosis] | |||
===Pathways=== | |||
Apoptosis occurs within extrinsic pathway and intrinsic pathway. Extrinsic pathway occurs by simulation of death receptor which is located on plasma membrane. (Ligands are signal molecules that they simulate death receptor.) Intrinsic pathway occurs by releasing of signals within mitochondria cell. (Cellular stress triggers intrinsic pathway. Cell stress is caused by DNA damage and heat shock.) [http://www.scq.ubc.ca/?p=350] | |||
Studying and understand pathways of apoptosis will help to prevent and treat diseases. | |||
====Defective Apoptotic Pathways=== | |||
Diseases appear by disorder or modification of apoptotic pathways. Disorder and modification prevent normal function of apoptosis. Because apoptosis does not notice “use-by-date”, cells live longer or replicate and produce more cells. When unnecessary cells live longer, they can be cancer or disease. | |||
=====HIV===== | |||
HIV, Human Immunodeficiency Virus, has gene that cannot kill infected cells by apoptosis pathway. It happens when host’s immune system becomes weak. The host’s immune system becomes weak, because of wrong pathway of apoptosis programs to kill immune cells. In other words, number of immune cells is decreased by wrong pathway of apoptosis. [http://www.scq.ubc.ca/?p=350] | |||
==Function of Apoptosis== | |||
Even though apoptosis is programmed cell death, it is used for medical reason. Apoptosis helps to form body shape and shape of organs. In immune system, apoptosis plays important role that eliminate aggressive immune cells. [http://www.nature.com/nature/insights/6805.html] | |||
==Cell damage or Infection== | |||
The reason is that apoptosis is important process is it prevents diseases and contronls unnecessary cells in body. When cells are damaged, apoptosis occurs and the cells die. If apoptosis does not occur, the damaged cells will be nutrients to other organisms. Later these organisms will grow and become diseases. Therefore, apoptosis is integral process in immune system. Apoptosis prevents cancer. When apoptosis does not occur well, the cells divide and develop more cells. Later those cells will be cancer or diseases. [http://en.wikipedia.org/wiki/Apoptosis] | |||
* [http://www.celldeath.de/encyclo/aporev/aporev.htm Introduction to Apoptosis] Celldeath | |||
* [http://www.apoptosisworld.com/ Apoptosis/] World Apoptosis World | |||
* [http://en.wikipedia.org/wiki/Apoptosis Apoptosis] Wikipedia | |||
* [http://www.scq.ubc.ca/?p=350 Apoptosis] The Science Creative Quarterly | |||
* [http://www.nature.com/nature/insights/6805.html Apoptosis] Nature.com | |||
* [http://www.esi-topics.com/apoptosis/ Apoptosis] Essential Science Indicators Special Topics | |||
[[Category:Cell biology]] | [[Category:Cell biology]] | ||
