What is the term for the process by which a cell engulfs large particles or cells?

Phagocytosis is the term used to describe the process by which a cell engulfs large particles or even other cells. It is a specialized form of endocytosis, where the cell membrane extends around the particle and then internalizes it into a vesicle known as a phagosome. This process is essential for immune cells, such as macrophages and neutrophils, which utilize phagocytosis to engulf and destroy pathogens and debris within the body. It plays a crucial role in the body's defense mechanisms and in maintaining tissue homeostasis by removing dead and damaged cells.

Other processes listed, such as exocytosis, involve the expulsion of material from the cell rather than engulfing it. Osmosis refers specifically to the movement of water across a semipermeable membrane, whereas pinocytosis is the process by which cells take in small amounts of liquid along with dissolved substances. Hence, phagocytosis is uniquely identified by its function of encapsulating larger particles, clearly distinguishing it from these other cellular processes.