Final answer:
The process by which cells capture proteins released by other cells is called endocytosis. It is an active transport process that can take several forms, including receptor-mediated endocytosis, pinocytosis, and phagocytosis.
Step-by-step explanation:
Cells communicate with each other by releasing chemicals and proteins, and the process by which they capture these proteins is called endocytosis. This mechanism involves internalizing large extracellular molecules such as proteins or even microorganisms. It is an active transport process where the cell membrane engulfs the substance to form a vesicle that then moves into the cytoplasm. There are different types of endocytosis, including phagocytosis, which targets large particles, pinocytosis which is non-specific ingestment of extracellular fluid, and receptor-mediated endocytosis which is highly specific to substances recognized by cell surface receptors. On the other hand, exocytosis is the process where cells export material, such as hormones and digestive enzymes, outside the cell by fusing vesicles with the plasma membrane and releasing the vesicle's contents.