I-Programmed Cell Death Apoptosis It is an important mode of cell death induced by suicide program through activation of some of its enzymes capable of degrading the cells' nuclear DNA and nuclear and cytoplasmic proteins.
A-PCD is as needed for proper development as mitosis (Physiological). B-PCD is needed to destroy cells that represent a threat to the integrity of the organisms (Pathological) and includes: 1-Cells infected with viruses. 2-Cells of the immune system. As Cell-mediated immune responses. the effector cells must be removed to prevent them from attacking body constituents. Defects in the apoptotic machinery are associated with autoimmune diseases as lupus erythematosus. 3-Cells with DNA damage. Cells respond to DNA damage by increasing their production of P53 (a potent inducer of apoptosis) 4-Cancer cells. Radiation and chemicals used in cancer therapy induce apoptosis.