Mitochondrial outer membrane permeabilization (MOMP), also known as the mitochondrial outer membrane permeability, is one of two ways apoptosis (a type of programmed cell death) can be activated.[1] It is part of the intrinsic pathway of apoptosis, also known as the mitochondrial pathway. MOMP is known as the point of no return in apoptosis. Once triggered, it results in the diffusion of proteins from the space between the inner and outer mitochondrial membranes into the cytosol.[2]