What is the term for the homeostatic process enabling targeted destruction of damaged proteins and organelles?

• A. Autophagy
• B. Apoptosis
• C. Necrosis
• D. Phagocytosis

Answer: (A)

Autophagy is the cellular cleanup pathway that targets damaged proteins and organelles for destruction inside lysosomes, helping maintain cellular homeostasis and quality control. In this process, a membrane structure engulfs cargo to form an autophagosome, which then fuses with a lysosome where enzymes degrade the contents and recycle the constituents. It can be selective, such as mitophagy for mitochondria, ensuring specifically damaged components are removed. This is different from apoptosis, which is programmed cell death; necrosis, which is uncontrolled cell death; and phagocytosis, which is uptake of extracellular material by immune cells. So autophagy best fits the described homeostatic targeting and degradation of intracellular components.