Which of the following is a characteristic feature that distinguishes apoptosis from necrosis?

Explanation

## Distinguishing Features of Apoptosis vs Necrosis **Key Point:** Apoptosis is a controlled, energy-dependent process that maintains membrane integrity, while necrosis is an uncontrolled, passive process resulting in membrane rupture and inflammation. ### Apoptosis Characteristics - Cell membrane remains **intact** initially, forming apoptotic bodies (membrane-bound fragments) - Chromatin condenses (pyknosis) and DNA fragments at internucleosomal sites - No inflammatory response — contents are contained within membrane - Requires ATP and activation of caspase cascade - Cell shrinks (pyknosis) ### Necrosis Characteristics - Cell membrane **ruptures** early, releasing cellular contents - Chromatin shows random fragmentation (not internucleosomal) - Triggers inflammatory response due to release of danger-associated molecular patterns (DAMPs) - Passive process, does not require ATP - Cell swells (oncosis) due to loss of ion homeostasis | Feature | Apoptosis | Necrosis | |---------|-----------|----------| | **Membrane integrity** | Preserved initially | Ruptured early | | **Cell size** | Shrinkage | Swelling | | **DNA fragmentation** | Internucleosomal (180–200 bp ladder) | Random | | **Inflammation** | Absent | Present | | **Energy requirement** | ATP-dependent | ATP-independent | | **Morphology** | Apoptotic bodies | Cell lysis | **High-Yield:** The intact membrane in apoptosis is the KEY feature that prevents spillage of cellular contents and inflammation, making it a "clean death" compared to necrosis. **Clinical Pearl:** Apoptosis is the normal mechanism of cell death in development, immune regulation, and tissue homeostasis. Necrosis occurs in pathological conditions (ischemia, trauma, severe inflammation).