coated vesicle

Endocytosis is a critical active transport process that allows cells to engulf extracellular materials, playing a pivotal role in nutrient uptake, immune response, and cellular communication. The diagram illustrates three distinct forms—phagocytosis, pinocytosis, and receptor-mediated endocytosis—each with unique mechanisms and selectivity levels for internalizing substances. This article provides an in-depth exploration of these processes, their anatomical structures, and their significance in maintaining cellular function and physiological balance.