Week 5 Apoptosis Flashcards Preview

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Flashcards in Week 5 Apoptosis Deck (17)
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1
Q

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

A

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

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

Nucleus dissolves in both!

2
Q

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

A

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

3
Q

name three diseases in which we see excessive apoptosis?

A

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

4
Q

name a disease associated with suppression of apoptosis

A

cancer

5
Q

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

A

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

Anti: Bcl-2 family

6
Q

what is the role of Bcl-2

A

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

7
Q

what is the role of Bid? activated?

A

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

8
Q

what is the role of Bax/Bak

A

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

9
Q

what is the role of Smac/Diablo

A

inhibits IAB which normally inhibits the caspase cascade

10
Q

what is the role of AIF

A

causes nuclear condensation and DNA fragmentation

11
Q

what is the role of Cyt C?

A

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

12
Q

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

A

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

13
Q

what is the extrinsic pathway of apoptosis?

A

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

14
Q

which caspase is seen in the extrinsic pathway? significance?

A

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

15
Q

what is Granzyme B? what is it released by?

A

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

16
Q

how does granzyme B function?

A

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

17
Q

what is the function of p53

A

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

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