Chapter 23 - Cell Death Flashcards
Physiological process - Cell death
Apoptosis
The difference between necrosis and apoptosis is;
- Necrosis is passive and damage neighbouring cells. Necrosis is caused by injury or disease -> NOT programmed cell death
- Apoptosis is an active process where no neighbouring cells are damaged. Apoptosis is programmed cell death.
What enzymes is used to generate ATP from glucose?
Lactate dehydrogenase (LDH)
Which enzyme is used for a general marker for necrotic cell death?
Lactate dehydrogenase (LDH)
What does the mitochondria of apoptopic cells release?
Cytochrome c
What happens with chromatin of apoptotic cells?
Segments and condence
Apoptotic cells are engulfed by;
- phagocytic cells
- macrophages
- dendritic cells
What cytokines are released by phagocytic cells that reduce the risk of inflammation from the cell death?
- Interleukin-10 (IL-10)
- Transforming growth factor- “Beta” (TGF-“beta”)
What does p53 do with a damaged cell?
P53 halt the cell cycle and stimulate apoptosis
What triggers programmed cell death?
The normal p53 binds to a p53-responsive element within the gene promoter of the proapoptotic protein Bax.
What happens if we have an abdnormal p53?
The Bax is not produced which means that the cell continues to survive and divide => it does not undergo apoptosis
Sonic hedgehog and apoptosis
During the embryonic development Shh has to attach to Patched 1(Ptc1) in order for the target cell to survive. If the Shh does not bind to Ptc then the target cell dies by undergoing apoptosis
Hemostasis
Is a balance between the cell death and proliferation
Cell death
- apoptosis
- necrosis
Cell proloferation
- cell replacement
- cell growth
Apoptosome
A large protein complex that requires ATP for its formation.
Internal cell death program
What triggers apoptosome?
Cytochrome c in the cytoplasm
Bax
- A proapoptotic protein
- Form a channel on the mitochondria which allows the cytochrom c to exit ->triggers the formation of apoptosome
What happens with the cytochrome c when it is in the cytoplasm?
- cytochrome c activates Apaf-1 adaptor protein
- Apaf-1 adaptor protein activates caspase 9 of the caspase proteolytic cascade that will cleave and destroy cellular proteins and DNA in order to cause cell death by apoptosis
What initiates apoptosis from external signals?
Death receptors belonging to the Tumour Necrosis Factor Receptor(TNFR) gene superfamily
What is the homologous cytoplasmic sequence possessed by those TNF members that do initoate cell death termed?
Death domain (DD)
Give examples of adaptor molecules that do contain DDs (death domains)?
- FADD (Fas-associated death domain)
- ## TRADD (TNFR-associated protein)The interact with the death receptors to transmit the apoptotic signal to death machinery, via activation of caspase 8 or 10
Pathological process - cell death
Necrosis
