Apoptosis: Difference between revisions
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Apoptosis (or programmed cell death) is one of the methods by which the [[The cell cycle|cell cycle]] is regulated. It can be in response to many things, for example: [[DNA|DNA]] in the cell being badly damaged, removal of dangerous cells or controlling cell numbers. The process of apoptosis is activated by the [[P53|p53 gene]] which starts a [[Cascade|cascade]] of events that eventually leads to [[ | Apoptosis (or programmed cell death) is one of the methods by which the [[The cell cycle|cell cycle]] is regulated. It can be in response to many things, for example: [[DNA|DNA]] in the cell being badly damaged, removal of dangerous cells or controlling cell numbers. The process of apoptosis is activated by the [[P53|p53 gene]] which starts a [[Cascade|cascade]] of events that eventually leads to [[Caspase|caspases]] in the cells being activated <ref>Becker W.Bertoni G.Hardin J.Kliensmith L.(2009)The world of the cell,7th edition,San Fransisco:Pearson. p590</ref>. Any damage to [[Mitochondria|mitochondria]] can cause cell death. The damaged mitochondria leak cytochrome C from between the two cell membranes, activating the [[Caspase|caspases]].These [[Caspase|caspases]] can then cleave [[Nuclear lamins|nuclear lamins]], activate [[DNAase|DNAase]] as well as cleave the [[Cytoskeleton|cytoskeleton]]. Cleavage of the nuclear lamin by[[Endonucleases|endonucleases]] leads to nuclear fragmentation. in addition, cleavage of the [[Cytoskeleton|cytoskeleton]], and cell to cell adhesion proteins by the same enzyme causes the apoptotic cell to round up and disengage from neighbouring cells. <ref>Alberts et al (2008) Molecular Biology of the Cell, 6th Edition, New York: Garland Science</ref> The damaged cell is then engulfed by phagocytosis.<br> | ||
Apoptosis can be initiated other ways for example, in tadpoles a [[Hormone|hormone]] is produced from the [[Thyroid gland|thyroid gland]] that causes apoptosis to occur in their tail when they are becoming an adult frog. This causes the cells in the tail to die and their tail disappears. <ref>Alberts B.Johnson A.Lewis J.Raff M.Roberts K.Walter P.(2008) molecular biology of the cell,5th edition,New york:Garland science. p1119</ref><ref>Alberts B.Johnson A.Lewis J.Raff M.Roberts K.Walter P.(2008) Molecular Biology of The Cell,5th edition,New york:Garland science. p1118</ref>.<br> | Apoptosis can be initiated other ways for example, in tadpoles a [[Hormone|hormone]] is produced from the [[Thyroid gland|thyroid gland]] that causes apoptosis to occur in their tail when they are becoming an adult frog. This causes the cells in the tail to die and their tail disappears. <ref>Alberts B.Johnson A.Lewis J.Raff M.Roberts K.Walter P.(2008) molecular biology of the cell,5th edition,New york:Garland science. p1119</ref><ref>Alberts B.Johnson A.Lewis J.Raff M.Roberts K.Walter P.(2008) Molecular Biology of The Cell,5th edition,New york:Garland science. p1118</ref>.<br> | ||
Revision as of 18:55, 1 December 2011
Apoptosis (or programmed cell death) is one of the methods by which the cell cycle is regulated. It can be in response to many things, for example: DNA in the cell being badly damaged, removal of dangerous cells or controlling cell numbers. The process of apoptosis is activated by the p53 gene which starts a cascade of events that eventually leads to caspases in the cells being activated [1]. Any damage to mitochondria can cause cell death. The damaged mitochondria leak cytochrome C from between the two cell membranes, activating the caspases.These caspases can then cleave nuclear lamins, activate DNAase as well as cleave the cytoskeleton. Cleavage of the nuclear lamin byendonucleases leads to nuclear fragmentation. in addition, cleavage of the cytoskeleton, and cell to cell adhesion proteins by the same enzyme causes the apoptotic cell to round up and disengage from neighbouring cells. [2] The damaged cell is then engulfed by phagocytosis.
Apoptosis can be initiated other ways for example, in tadpoles a hormone is produced from the thyroid gland that causes apoptosis to occur in their tail when they are becoming an adult frog. This causes the cells in the tail to die and their tail disappears. [3][4].
References:
- ↑ Becker W.Bertoni G.Hardin J.Kliensmith L.(2009)The world of the cell,7th edition,San Fransisco:Pearson. p590
- ↑ Alberts et al (2008) Molecular Biology of the Cell, 6th Edition, New York: Garland Science
- ↑ Alberts B.Johnson A.Lewis J.Raff M.Roberts K.Walter P.(2008) molecular biology of the cell,5th edition,New york:Garland science. p1119
- ↑ Alberts B.Johnson A.Lewis J.Raff M.Roberts K.Walter P.(2008) Molecular Biology of The Cell,5th edition,New york:Garland science. p1118