Apoptosis is programmed cell death, the body's normal method of disposing of damaged, unwanted, or unneeded cells. The usual characteristics that define a cell undergoing apoptosis is nuclear defragmentation by endogeneous nucleases, the production of apoptotic bodies and enhanced synthesis of cyclic AMP and reduced NAD in the rough endoplasmic reticulum, in addition to augmented secretion of vacuoles (primarily of the aforementioned apoptotic bodies and glycoproteins). Mitchondria and chloroplasts, the chief sites of photosynthesis and aerobic respiration respectively, are secreted.
Apoptosis and subsequent autolysis of cell organelles, such as the cytoskeleton, is the converse of necrosis. Necrosis is disorganised cell death, often excuted by uncontrolled autoimmune responses and terracinogenics.