What is the process called when large particles are engulfed by the cell membrane?

The process by which large particles are engulfed by the cell membrane is known as phagocytosis. This is a specific type of endocytosis, where the cell membrane extends around a particle, forming an enclosed vesicle, or phagosome, which is then brought into the cell. Phagocytosis is essential for various cellular functions, including the immune response, where immune cells like macrophages and neutrophils engulf pathogens and debris.

While endocytosis broadly encompasses all processes where the cell membrane engulfs substances to bring them into the cell, phagocytosis specifically refers to the uptake of large particles. Exocytosis, on the other hand, is the process of vesicles fusing with the cell membrane to expel contents from the cell, and osmosis pertains to the passive movement of water across a semipermeable membrane, not the engulfing of particles. Understanding these distinctions helps clarify the specific role of phagocytosis in cellular processes and immune defense mechanisms.