Week 5 Apoptosis Flashcards Preview

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Flashcards in Week 5 Apoptosis Deck (17):

Contrast Necrosis and Apoptosis: stimuli, morphology, host response, insult severity, nucleus dissolution

Necrosis: pathologic, cell swelling and lysis, inflammation, greater insults

Apoptosis: physiologic or pahtologic, cell shrinking, no inflammation, lesser insult

Nucleus dissolves in both!


what is the general/morphological progresssion of a cell undergoing apoptosis

nucleus condenses and fragments-->part of the cell Bleb and form apopotic bodies that are eaten by phagocytes


name three diseases in which we see excessive apoptosis?

AIDs (excessive loss of lymphocytes), Alzheimers disease (neuron loss), stroke


name a disease associated with suppression of apoptosis



what are the pro-apoptotic and anti-apoptotic Bcl-2 subgroups

Pro: Bax family (Bax/Bak), BH2-only family (Bid)

Anti: Bcl-2 family


what is the role of Bcl-2

when there is not cell stress Bcl-2 binds and inhibits Bax/Bik preventing them from inducing apoptosis


what is the role of Bid? activated?

under cell stress Bid is cleaved (caspase -8 or granzyme-B) and inhibits Bcl-2 binding and thus frees Bax/Bak


what is the role of Bax/Bak

when not sequestered Bax/bak create a pore in the mitochondrial membrane and release Cyt C, AIF, and Smac/Diablo


what is the role of Smac/Diablo

inhibits IAB which normally inhibits the caspase cascade


what is the role of AIF

causes nuclear condensation and DNA fragmentation


what is the role of Cyt C?

complexes with Apaf-1 to form an apatosome that activates procaspase-9


Activated pro-caspase-9 (caspase-9) does what

initiates caspase cascade which eventually activates execution caspases that degrade cellular components and lead to apoptosis


what is the extrinsic pathway of apoptosis?

death receptors at cell surface are sensitive to external signals that mediate apoptosis.


which caspase is seen in the extrinsic pathway? significance?

caspase-8 (this is the same caspase that activates Bid of the intrinsic pathway, crosstalk!)


what is Granzyme B? what is it released by?

a Ser protease that is released by cytotoxic T cells and NK cells


how does granzyme B function?

granzyme-B is released with perforin which enables it to enter cells. once in the cell granzyme-B activates Bid, Caspase 3 and 8.


what is the function of p53

tumor suppressor: promotes apoptosis. (Increases Bid transcription, increases death receptors, promotes Bax/Bak activity)

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