Cellular Adaptation & Cell Death

Question 1

E.g. of death receptor ligands

Answer 1

1. TNF-a
2. TRAIL
3. FasL

Question 2

E.g. of death receptors

Answer 2

1. TNF

2. Fas

Question 3

Describe apoptosis via extrinsic pathway

Answer 3

1. Ligands e.g., TNF-a, Fax-L & TRAIL bind death receptors e.g., TNF & Fax
2. Initiator caspases like caspase 8 activated
3. Executioner caspases like caspase 3 activated
4. Endonuclease activated & cytoskeleton degraded
5. Membrane bleb
6. Apoptotic body
7. Phagocytosis

Question 4

Describe apoptosis via intrinsic pathway

Answer 4

1. p53 activated
2. Pro-apoptotic Bcl-2 proteins like Bak, Bax & Bad activated
3. Outer membrane of mitochondria becomes more permeable
4. Cytochrome c released into cytosol
5. Cytochrome c forms complex called apoptosome w/ APAF-1
6. Apoptosome converts pro-caspase 9 into caspase 9
7. Caspase 9 activates executioner caspase like caspase 3
8. Endonuclease activated & cytoskeleton degraded
9. Membrane blebbing
10. Apoptotic body
11. Phagocytosis

Question 5

Sites of gangrenous necrosis

Answer 5

1. Lower limbs
2. Appendix
3. Gall bladder
4. Intestines

Question 6

How does fibrinoid necrosis happen?

Answer 6

1. Antigen-antibody complex formed
2. Ag-Ab complex deposits on blood vessel
3. Complement cascade initiated
4. Neutrophils release lysosomal enzymes
5. Fibrinoid necrosis