Which of the following features histologically and biochemically distinguishes apoptosis from necrosis?

• A Apoptosis: random DNA fragmentation, cell swelling, organelle disruption, inflammation present
• B Apoptosis: internucleosomal (ladder) DNA fragmentation, cell shrinkage, apoptotic bodies, NO inflammation ✓
• C Necrosis: condensed chromatin, nuclear fragmentation into apoptotic bodies, membrane blebbing
• D Necrosis: ATP-dependent process, caspase activation, lipid asymmetry with phosphatidylserine exposure

Explanation

Apoptosis is characterized by: internucleosomal (oligonucleosomal ladder pattern) DNA cleavage by caspase-activated DNase (CAD); nuclear pyknosis and karyorrhexis; cell shrinkage with condensed cytoplasm; membrane blebbing and fragmentation into apoptotic bodies that are phagocytosed without triggering inflammation (phosphatidylserine flips to outer leaflet signaling macrophage recognition). Necrosis shows random (non-ladder) DNA digestion, cell swelling and rupture, organelle dissolution, and prominent inflammation due to leakage of DAMPs. Necrosis is typically passive; apoptosis is energy (ATP)-dependent and caspase-mediated.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.