the number of times a cell can divide before apoptosis usually 40
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what are the characteristics of apoptosis?
cell shrinkage, nuclear breakdown, require protein syn as act as control (progrmamed),phagocytosis
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what drug shows protein synthesis is needed for apoptosis why?
cycloheximide- drug that stops protein syntheis, apoptosis no longer happens
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what is necrosis associated with:
physical damage, infections, acute toxicity, acute hypoxia/ischaemia, rapid loss of cell energy
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what physical damage can there be for necrosis?
gut epithelium needs to be replaced, drying eg nasal epithelium, trauma eg cuts and burns
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what do most CED genes do?
recognition of engulfment (most)
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4 key CED genes?
EGL-1, CED9, CED 4, CED 3
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What CED genes are antiapoptotic (give excess adult cells)?
ced 3 and ced 4
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which CED genes gives massive cell death (pro-apoptosis)?
CED 9
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what is apoptosis initiated by?
EGL-1
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order of apoptosis in C.elegans?
EGL-1 -/ CED 9 -/ CED 4 ---> CED 3
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order of apoptosis in mammals?
BH3 -/ BCL-2 -/ APAF-1 ---> Caspase 9
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what are caspases activated by?
proteolysis -> cascade effect
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what are caspases?
executioners of cell death
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how many mammalian homologoes are there or CED3?`
10+
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what is caspase 3 important in?
development (YAMA)
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what does caspase 3 break down?
DNA repair enzyme, Lamin A, hungtindin (huntingtons disease gene product)
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what is the dna repair enzyme caspase 3 breaks down?
(PARP = poly ADP-ribosepolymerase)
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what are the 2 pathways that activate apoptosis?
intrinsic and extrinsic
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how many death receptors are?
5
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what do Fas-ligand mutations lead to?
autoimmune disorders, apoptosis of wanted cells
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what do the death receptors do?
indirectly (DISC) activate caspases
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what is DISC ?
death inducing signalling complex
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what happens in the intrinsic pathway?
cytochrome c released from mito, cytochrome c binds to Apaf-1, bind product to procaspase 9, activates procaspae 9, cproteolysis
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is there just one trigger for cytochrome c release?
no numerous triggers
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is Apaf-1 usually active?
no only becomes active when damage to mitochondria
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what stimulates progenitors in the haemopotic system to produce many offspring to increase nums if low?
colony stimulating factors
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what happens with the withdrawal of colony stimulating factors?
causes apoptosis
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what sort of stem cells are blood cells from the bone marow?
pluripotent
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what happens if theres little RBCs?
kidneys produce mpre erythropoeietin
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why does withdrawal of CSF's cause apoptosis?
PKB uses ATP are phosphorylated become active, induces phosphorylation of other genes like gene reg protein for cell death promoting genes
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whats going on with Bad and Bcl-2?
PKB gives phosphate to Bad, Bads bound to Bcl-2, when Bads phosphorylated Bad becomes inactive so Bcl2 is free and becomes active and inhibits apoptosis
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whats overcome leading to necrosis?
cell defences
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what is apoptosis associated with?
dev cell loss. senscence-hayflicks num, chronic toxicity, removal of growth factros, detatchmentfrom substrate (Anoikis = homeless cell)
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Other cards in this set
Card 2
Front
what is apoptosis?
Back
programmed cell death, cell suicide
Card 3
Front
are the cells in the middle of a isacehmiac brain necrosis or apoptosis cells?
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