Apoptosis is a normal and controlled form of cell death that plays an important role in multicellular organisms. It occurs through either an intrinsic or extrinsic pathway. The intrinsic pathway involves signals within the cell such as mitochondrial or endoplasmic reticulum damage, while the extrinsic pathway involves death receptors on the cell surface that activate caspases when bound by ligands. Apoptosis helps shape tissues and organs during development, eliminates unnecessary or harmful cells, and prevents diseases like cancer from developing.

2. internet

3. internet

4.  The death of cells which occurs as a normal
and controlled part of an organism's growth
or development. (medical dic .)
 Form of cell death in which a programmed
sequence of events leads to the elimination
of cells without releasing harmful substances
into the surrounding area. (medical dic .)
 In Greek, apoptosis means falling off(national
library of medicene) 1

5. Apoptosis is an active process and plays an
important role in multicellular organisms in that it
regulates and adjusts cell population. (national library of
medicene)
Apoptosis, is a necessary process in both animal
tissue and plant tissue development. (national library of
medicene)
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Apoptosis VS. NecrosisApoptosis VS. Necrosis

8. Mitochondrial pathway
Endoplasmic reticulum pathway
TNF receptor
Fas(CD95)
TRAIL
Extrinsic pathway
Intrinsic pathway
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9.  involves transmembrane death receptors that are members of the
tumor necrosis factor (TNF) receptor gene superfamily.
 Members of this receptor family bind to extrinsic ligands and transduce
intracellular signals that ultimately result in the destruction of the cell.
 The most well characterized ligands of these receptors to date are:
FasL, TNF-alpha, Apo3L, and Apo2L.
 Corresponding receptors are:
FasR, TNFR1, DR3, and DR4/DR5, respectively.
The signal transduction of the extrinsic pathway involves several
caspases which are proteases with specific cellular targets.
Ref. : slide share
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10. DD
DED
FADD
FLIDs
Pro casp 8
casp 8
Effector
casp
Apoptosis
Death receptor
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11.  involves non-receptor–mediated intracellular signals
 inducing activities in the mitochondria that initiate apoptosis.
 Stimuli for the intrinsic pathway include viral infections or damage to the
cell by:
toxins, free radicals, or radiation.
Damage to the cellular DNA can also induce the activation of the
intrinsic pathway for programmed cell death.
Intrinsic pathway occurs by releasing of signals within mitochondria
cells.
Ref. : slide share
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12. (Hashemi et all. 2003)

13. Ref. : Biochemistry of Signal Transduction and Regulation
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internet

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internet

19.  Apoptosis helps to form the overall body shape and the shape of
organs
 Apoptosis plays an important role that eliminates aggressive
immune cells.
 Apoptosis is an important process in that it prevents diseases and
controls unnecessary cells within the body.
 If apoptosis does not occur, the damaged cells will be nutrients to
other organisms.
 Apoptosis prevents cancer.
(When apoptosis does not occur well, the cells divide and develop
more cells.)
Ref. : national library of medicine
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20. End show
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21. national library of medicine

22. klinphys.charite.de

23. internet