CELL DEATH

Question 1

What is apoptosis?

Answer 1

programmed cell death

Question 2

What is necrosis?

Answer 2

non-programmed cell death

Question 3

Describe fully the process of apoptosis

Answer 3

1) - chromatin condenses
- microvilli contract
- int ercellular functions break

2) cell shrinks
3) breaks up into enclosed apoptotic bodies
4) phagocytosed by roving macrophages

Question 4

Describe fully the process of necrosis

Answer 4

1) trauma causes cell and organelle swelling
- chromatin condenses
- fluid rushes in

2) causes disolution of cell compartments

3) cell lysis
phagocytic invasion
inflammation

Question 5

Key differences between apoptosis and necrosis

Answer 5

• apoptosis is programmed
• apoptosis affects single cells
• apoptosis shows no inflammation
• apoptosis involves specific gene activity
• necrosis responds to large scale trauma, DNA genomic damage
• necrosis affects clumps of cells
• necrosis shows inflammation
• necrosis shows no specific gene activity

Question 6

Key use of apoptosis in development

Answer 6

tissue remodelling

eg. digits

Question 7

How did C.elegans model system identify conserved apoptotic regulators?

Answer 7

• showed that 4 ced genes have roles in apoptotic development

Question 8

What was shown in ced-3 or ced-4 mutants in C.elegans?

Answer 8

cells that should’ve undergone apoptosis survived

Question 9

What about ced-9 mutants? What does this suggest about its WT function?

Answer 9

too much cell death

- usually suppresses cell death

Question 10

Ced-9 equivalent in humans?

In cancer cells ced-9 is over-expressed keeping them ___.

Answer 10

Bcl-2

alive

Question 11

Distinguish main factor between the intrinsic and extrinsic pathways.

Answer 11

INTRINSIC - signal comes from within the cell (cytochrome c)

EXTRINSIC - signal arrives from killer lymphocyte

Question 12

What is unique about procaspase-9?

Function?

Answer 12

it needs pro-domain to be cleaved to be activated

• activates executioner caspases

Question 13

What triggers the intrinsic suicide pathway?

Answer 13

too much tissue damage and stress

Question 14

What occurs in the intrinsic pathway?

Answer 14

1) change induced in the mitochondrial membrane that causes the release of cytochrome C
2) triggers apoptotic pathway
3) activates apoptosome pro domain removed from pro-caspase- 9 (Apaf1 involved somewhere)
4) executioner caspases can then chop up/ disassemble the cell

Question 15

What are caspases?

Answer 15

specialised proteases that celeave C terminal of aspartic residues

Question 16

What does DISC stand for?

Answer 16

death inducing signalling complex

Question 17

Extrinsic pathway ((a)) involves killer (b) which have Fas (c) that bind to Fas death (d). These then form a DISC, to recruit (e).

Answer 17

a) murder
b) lymphocytes
c) ligands
d) receptors
e) caspases

Question 18

What do survival factors do?

What does Bcl-2 do?

Answer 18

• prevent apoptosis

- keeps cytochrome c inside of cells

Question 19

CAD can degrade DNA’s ___ structure, usually inhibited by ___.

Answer 19

lamin

ICAD