Autophagy and Autolysis
Autophagy
is a housekeeping process in which old organelles are degraded and recycled.
Intracellular membrane wraps around the organelle to be degraded
↓
forms a double membrane structure called autophagosome
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autophagosome merges with lysosome
↓ Lysosomal hydrolases digest materials inside the autophagosome
↓ released nutrients are reused by the cell.
Autophagy also supplies vital nutrients to cells when their supply from outside is scarce.
Autolysis
Damaged cells are removed by autolysis.
Trauma/heat/cold/chemical etc
↓
damage to the cell
↓
Lysosomes rupture
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Hydrolase enzymes are released
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1. If the damage is limited → only damaged structures are digested → cell is repaired.
2. If the damage is widespread and severe → entire cell is digested and removed → new cell is formed by mitosis of adjacent cell.