The document discusses the differences between apoptosis and necrosis. Apoptosis is a highly regulated and programmed process where cells undergo controlled death without inflammatory consequences. It occurs through mitochondrial changes, DNA fragmentation, cellular shrinkage, and formation of membrane-bound apoptotic bodies that are phagocytosed. In contrast, necrosis is unregulated cell death caused by external factors that results in cell swelling and rupture, releasing intracellular contents and triggering inflammation. The document outlines the multi-step process of apoptosis and provides examples of where it is important, such as in development and elimination of damaged cells.