Final answer:
Autophagy, which means "self-eating", is the process by which a cell degrades its worn out organelles through lysosomal enzymes. It is vital for cellular renewal and the overall cell cycle, as well as for destroying pathogens by phagocytosis, and contributes to controlled cell death called apoptosis.
Step-by-step explanation:
By the process called autophagy, which literally means "self-eating", worn out organelles are destroyed, and then replaced. Autophagy is a lysosomal breakdown of a cell's own components. During this process, cellular structures like damaged organelles are enveloped by autophagosomes, which are vesicles that then fuse with lysosomes. The hydrolytic enzymes within the lysosomes degrade the content enveloped by autophagosomes.
This process is crucial for the cell cycle, which is the life cycle of a single cell, from its birth until its division into two new daughter cells. The autophagic process ensures that cells can renew themselves and maintain healthy functioning by removing and recycling cellular components. Additionally, the lysosomes are part of the endomembrane system and perform vital roles such as destroying pathogens through phagocytosis, where infectious agents are engulfed and digested. Lysosome-induced cell autolysis is also a form of controlled cell death, known as apoptosis.