cell death Flashcards
what are some of the key characteristics of necrosis?
inflammatory process - induces inflammatory cells
involves the leaking of cell contents out
pathological process
where does coagulative necrosis most commonly occur and what is it like?
occurs in most tissues e.g. the heart
where does colliquative necrosis commonly occur?
liquified mass (e.g. the brain)
where does caseous necrosis commonly occur?
commonly occurs with tuberculosis
what is apoptosis?
basically is cell fragmentation (sometimes DNA fragmentation) and does not involve inflammation or the spilling of cell contents
what is PARP involved in? (poly ADP ribose polymerase)
enzyme involved in DNA repair
what molecule is moved to present on the outside of cells undergoing apoptosis to promote nearby cells and macrophages phagocytosing it?
phosphatidylserine
what are the two types of extrinsic mediated apoptosis?
receptor mediated and NK (T cell) mediated
what are some examples of receptors and signally molecules which can induce apoptosis?
TNF alpha and beta
Fas CD95
what enzymes are activated by these receptor actions?
capsases (proteases which inactivate enzymes involved in DNA repair and break down cell contents and can cause DNA fragmentation)
what is the name of the protein CD8 T cells use to create a pore in the target cell?
perforin
what is the name of the molecule which activates caspases inside the cell to start apoptosis?
granzyme
what are two types of intrinsic mediated apoptosis?
mitochondrial damage and DNA damage (e.g. by radiation)
what molecule does the mitochondria release through the open PTP pore in response to stress?
cytochrome C
what does cytochrome C bind to once it has been released from the mitochondria?
Apaf-1
what does cytochrome C and Apaf bind to in the step before the activation of the CASPASE CASCADE?
inactive procaspase 9 (this is then activated to caspase 9)
what does the circular apoptosome (apaf-1 + procaspase 9 + cytochrome C + adaptor protein) do?
allows apoptosis to happen quickly and easily by having a high concentration to start the Capsize cascade
what can p53 recognise?
DNA damage
what are the three things p53 can do once it has detected DNA damage?
- DNA repair
- stop the cell cycle
- promote apoptosis by increasing BAX acting on the mitochondria
what does BCL2 promote?
anti-apoptosis (promotes cell survival)
what does BAX gene promote?
apoptosis
what type of mutation can cause an over expression of Bcl2 and therefore cause tumour formation?
translocation mutation of bcl2 gene next to a gene causing over expression
what are IAPs?
inhibitors of apoptosis
what is proptosis?
microbial trigger of apoptosis, final step is pro inflammatory
what is anoikis?
when cells lose contact with the BM, apoptosis is induced
