4C Apoptosis

Question 1

What is apoptosis/programmed cell death

Answer 1

The controlled death of
cells in the body.

Question 2

Purpose

Answer 2

When a cell begins to:
- Malfunction
- Damaged
- Unnecessary

Remove them

Question 3

Identify + outline the mitochondrial pathway/intrinsic pathway

Answer 3

1. Cell stress (damage/malfunctioning)
2. Mitochondria detect this
3. Mitochondria release cytochrome C
4. Cytochrome C binds to cytosolic proteins to form an apoptosome
5. Apoptosome activates capase enzymes

Question 4

Identify + outline the death receptor pathway

Answer 4

• Death Signalling molecules released by other cells (e.g. immune cells)
• These molecules are recognised by death receptors
• When these molecules bind to the receptors, caspase enzymes is released into the cell
• Caspase enzyme triggers apoptosis

Question 5

Outline the three stages of apoptosis now that it has been activated

Answer 5

1. Capase enzyme activated
2. Digestion of cell contents
   - Capase cleave proteins
   - Organelles break down
3. Cell shrinks as contents break down
4. Membrane blebbing and breakage
   - Cytoskeleton digested
   - Membrane wraps and detaches from cell in apoptotic bodies

Question 6

After - Phagocytosis

Answer 6

• Endocytosis of apoptotic bodies by phagocytes