Which of the following distinguishes apoptosis from necrosis at the ultrastructural level?
- A Mitochondrial swelling with flocculent densities
- B Chromatin condensation into crescents with membrane blebbing forming apoptotic bodies ✓
- C Nuclear pyknosis followed by karyorrhexis and karyolysis
- D Cell swelling with rupture of plasma membrane causing inflammation
Correct answer: B. Chromatin condensation into crescents with membrane blebbing forming apoptotic bodies
Explanation
Apoptosis is characterized ultrastructurally by chromatin condensation into crescent-shaped masses (pyknosis), cell shrinkage, membrane blebbing, and fragmentation into membrane-bound apoptotic bodies that are phagocytosed without inflammation. Necrosis shows cell swelling, organelle disruption, and plasma membrane rupture with inflammatory reaction. Flocculent mitochondrial densities and karyorrhexis/karyolysis are features of necrosis.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.