AP BIOLOGY

Detailed explanation-1: -The two main pathways of apoptosis are extrinsic and intrinsic as well as a perforin/granzyme pathway. Each requires specific triggering signals to begin an energy-dependent cascade of molecular events. Each pathway activates its own initiator caspase (8, 9, 10) which in turn will activate the executioner caspase-3.

Detailed explanation-2: -Apoptosis, one of the better-known forms of regulated cell death, is activated when cell-surface death receptors like Fas are engaged by their ligands (the extrinsic pathway) or when BCL-2-family pro-apoptotic proteins cause the permeabilization of the mitochondrial outer membrane (the intrinsic pathway).

Detailed explanation-3: -In both the intrinsic and extrinsic pathway of apoptosis, signaling results in the activation of a family of Cys (Cysteine) proteases, named caspases, that act in a proteolytic cascade to dismantle and remove the dying cell (1).

Detailed explanation-4: -The members of the Bcl-2 family of proteins are the central regulators of the intrinsic apoptotic pathway.

Detailed explanation-5: -The intrinsic apoptosis pathway begins when an injury occurs within the cell. Intrinsic stresses such as oncogenes, direct DNA damage, hypoxia, and survival factor deprivation, can activate the intrinsic apoptotic pathway.