According to the material, apoptosis is often accomplished by which of the following?

• A. By autophagy
• B. By leaky or popping lysosomes
• C. By mitochondria isolation
• D. By necrosis

Answer: (B)

Apoptosis can be triggered through multiple proteolytic pathways, not just the mitochondria-centered route. When lysosomes become destabilized, their membranes leak hydrolytic enzymes, notably cathepsins, into the cytosol. These proteases can either directly activate caspases or modify other pro-apoptotic proteins (for example, cleaving Bid to tBid), which then promotes mitochondrial outer membrane permeabilization and the release of cytochrome c. This activates the caspase cascade that executes programmed cell death. So, leaky lysosomes contribute to apoptosis by unleashing proteases that feed into the intrinsic death pathway, providing a viable route to the apoptotic program in addition to mitochondrial signals and death-receptor signaling.