10.4.1 differentiate between necrosis and apoptosis with examples
| Feature | Necrosis | Apoptosis |
| Definition | Uncontrolled, accidental cell death caused by external factors, leading to cell rupture and inflammation. | Programmed, controlled cell death that eliminates unnecessary or damaged cells without inflammation. |
| Cause | External injuries or stressors such as trauma, infection, toxins, or lack of oxygen/blood supply. | Internally regulated process triggered by developmental signals, DNA damage, or immune responses. |
| Mechanism | – Cell membrane ruptures due to swelling. – Organelles and cytoplasm are damaged. – Contents leak, causing inflammation. | – Cell shrinks, chromatin condenses. – DNA fragments in an orderly manner. – Cell forms apoptotic bodies, which are phagocytosed. |
| Energy Requirement | Passive process; no energy required. | Active process; requires ATP. |
| Inflammation | Causes inflammation due to release of cellular contents. | No inflammation; apoptotic bodies are cleared by phagocytes. |
| Regulation | Unregulated, chaotic process. | Highly regulated by genetic and biochemical pathways (e.g., caspase activation). |
| Impact on Tissue | Damages surrounding tissue due to inflammation. | Does not harm surrounding tissue; often beneficial. |
| Examples | – Tissue death from frostbite. – Heart muscle damage during a heart attack (myocardial infarction). | – Removal of tadpole tail cells during frog metamorphosis. – Elimination of damaged cells in response to DNA damage (e.g., in cancer prevention). |