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Senescence: Difference between revisions
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[[Image: | [[Image:Old Man.jpg|thumb|150px|right|The results of aging]] | ||
Senscence is the process of the aging of cells which eventually leads to cell death. Many people think that if senescence was prevented, people could live much longer, if not forever. There is even an area of science, called gerentology, that studies the aging process in order to prevent age-related diseases and disabilities. | Senscence is the process of the aging of cells which eventually leads to cell death. Many people think that if senescence was prevented, people could live much longer, if not forever. There is even an area of science, called gerentology, that studies the aging process in order to prevent age-related diseases and disabilities. | ||
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== Celular Senescence == | == Celular Senescence == | ||
[[Image:Telomere caps.gif|thumb|250px| | [[Image:Telomere caps.gif|thumb|250px|left|The white spots at the end of the chromosomes are telomere caps]] | ||
Cellular scenescence is the reproduction limits of normal cells. Most normal cells can divide up to 40 or 60 times before they are unable to divide anymore. This is referred to as he Hayflick Limit, after Dr. Leonard Hayflick who discovered cellular senscence. Some cells do not have this limit, though. These cells are cancer cells, and they can divide infinitely. [http://websites.afar.org/site/PageServer?pagename=IA_b_sene_01_what] | Cellular scenescence is the reproduction limits of normal cells. Most normal cells can divide up to 40 or 60 times before they are unable to divide anymore. This is referred to as he Hayflick Limit, after Dr. Leonard Hayflick who discovered cellular senscence. Some cells do not have this limit, though. These cells are cancer cells, and they can divide infinitely. [http://websites.afar.org/site/PageServer?pagename=IA_b_sene_01_what] | ||
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== Apoptosis == | == Apoptosis == | ||
[[Image:Apoptosis.jpg|thumb|150px| | [[Image:Apoptosis.jpg|thumb|150px|right|Flower dying through apoptosis]] | ||
Programmed cell death is called [[apoptosis]]. This is commonly seen in plants, but can happen in all kinds of organisms. There are two main reasons for an organism to kill its own cells: It is needed for proper dvelopment, and it is needed to destroy cells that pose a threat to the entire organism. This can be seen in the development of the human brain, where synapses must form by getting rid of surplus cells through apoptosis, or destroying cancer cells or cells infected with viruses through induced apoptosis. [http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/A/Apoptosis.html] | Programmed cell death is called [[apoptosis]]. This is commonly seen in plants, but can happen in all kinds of organisms. There are two main reasons for an organism to kill its own cells: It is needed for proper dvelopment, and it is needed to destroy cells that pose a threat to the entire organism. This can be seen in the development of the human brain, where synapses must form by getting rid of surplus cells through apoptosis, or destroying cancer cells or cells infected with viruses through induced apoptosis. [http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/A/Apoptosis.html] | ||
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== Senesence Hormones == | == Senesence Hormones == | ||
[[Image:Celldeath.JPG|thumb|350px|left|Cell death]] | |||
[[Ethylene]] is an important senescence hormone in plants because it stimulates plant growth and speeds up the process of apoptosis. Ethylene also is involved in the abscission of leaves and the fading of flowers. | [[Ethylene]] is an important senescence hormone in plants because it stimulates plant growth and speeds up the process of apoptosis. Ethylene also is involved in the abscission of leaves and the fading of flowers. | ||
