The following cellular process involves formation of double membrane vesicles that engulf and degrade the cellular organelles and macromolecules
The following cellular process involves formation of double membrane vesicles that engulf and degrade the cellular organelles and macromolecules
Select an option to attempt
Correct Answer: Option C
Explanation
Autophagy ('self-eating') is a lysosomal degradation pathway for cytoplasmic components including damaged organelles (mitophagy, reticulophagy), protein aggregates, and intracellular pathogens. Key feature: the formation of a DOUBLE-MEMBRANE structure (the phagophore/isolation membrane) that elongates and sequesters cargo, forming the AUTOPHAGOSOME (double-membrane vesicle). The autophagosome then fuses with lysosomes to form autolysosomes, where lysosomal enzymes (acid hydrolases) degrade the contents. Signals inducing autophagy: nutrient starvation (mTORC1 inhibition), hypoxia, ER stress, pathogen invasion. Necrosis — unregulated cell death (no vesicle). Apoptosis — programmed cell death by caspases, forms apoptotic bodies (single-membrane blebs). Macropinocytosis — large-scale actin-driven plasma membrane ruffling engulfing extracellular fluid; single-membrane macropinosomes.