What are the roles of autophagy in cellular processes?

Autophagy plays a key role in several critical cellular processes by facilitating the degradation and recycling of malformed and dysfunctional cellular components. 

It serves as a quality control mechanism, selectively removing damaged or nonfunctional organelles, misfolded proteins, and other cellular debris. This recycling process helps maintain cellular homeostasis, adapt to stress conditions, and provides essential nutrients and energy sources during times of scarcity or metabolic demands. 

Autophagy also plays a key role in the survival of cellular organisms. It protects against cell death by providing the cells with essential nutrients and promotes cell survival by degrading damaged and dysfunctional proteins and organelles, and facilitating bio-energetic homeostasis. 

Another pivotal role of autophagy in cellular processes is as a host defense mechanism. Autophagy contributes to immunity by killing cells that are infected by foreign pathogens, preventing the infection from spreading.