Programmed Cell Death; Active Cell Death
Apoptosis was initially characterized by morphological changes of dying cells. During apoptosis cells shrink, and microvilli on the plasma membrane disappear. The nucleus is also condensed and fragmented. At the final stage of apoptosis the cells themselves are fragmented with all cellular contents inside. One of the biochemical hallmarks of apoptosis is the fragmentation of chromosomal DNA into nucleosome size units (180 bp).