This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
Internucleosomal cleavage of DNA is characteristic of- 
Select and explain. 
A. Reversible cell injury, B. Irreversible cell injury, C. Necrosis, D. Apoptosis
D: Apoptosis
Answer: D: Apoptosis 
Explanation: Ans. is 'd' i.e., Apoptosiso In apoptosis first there is breakdown of DNA into large 50-300- kilobase pieces.o Subsequently these DNA pieces undergogo internucleosomal cleavage to yield oligonucleosomes in multiples of 180-200 base pairs.o These Oligonucleosomes fragments are visualized by agarose gel electrophoresis as DNA ladders. o The internucleosomal cleavage is brought about by Cal+ and Mg2+ dependent endonucleases. Note: Internucleosomal DNA cleavage is not specific for Apoptosis. (can be seen in necrosis too)