chapter  4
40 Pages

- Apoptotic Regulations

The various components of multicellular organisms involve large-scale reshaping facilitated by well-coordinated cell growth and cell death. Multicellular organisms have an evolved controlled mechanism for cell death, which is known as apoptosis or programmed cell death (PCD). Apoptosis is characterized by a series of biochemical and morphological changes like blebbing, loss of asymmetry and attachment of cell membrane, cell shrinkage, nuclear fragmentation, chromatin condensation, and chromosomal DNA fragmentation. Apoptosis is an integral part of the multicellular organism, having its presence right from developmental stages to adult life. Apoptosis is initiated by a variety of external or internal stimuli and happens by a well-controlled mechanism. The controlled and coordinated steps involved in apoptotic cell death make it different from other types of cell death, like necrosis, which involves uncontrolled cell death resulting in lysis of cells, and invoking inflammatory responses and causing potentially serious health problems. Apoptosis, along with cell proliferation, is responsible for shaping tissues and organs during developmental periods; for instance, apoptosis of cells located in between the toes allows for their separation (Zuzarte-Luis and Hurle, 2002). Apoptosis also plays an important role in the immune system by selective killing ineffective or self-reactive T-cells. T-cells are responsible for destroying damaged or infected cells in the body.