Final answer:
In phagocytosis, the cell membrane's extensions, pseudopodia, engulf particles to form a vesicle known as a phagosome, which is vital for cellular digestion and immunity.
Step-by-step explanation:
In phagocytosis, pseudopodia encloses materials to be engulfed in a vesicle called a phagosome.
During phagocytosis, the cell's plasma membrane extends outward to form pseudopodia, which engulfs the target particle. This action creates a phagosome, or a food vacuole, inside the cell. Phagocytes, such as white blood cells, use this process to eliminate foreign particles from the body.
After engulfment, the phagosome fuses with a lysosome, where activated hydrolytic enzymes digest the material. Eventually, the remnants are released from the cell via exocytosis. This process is vital to the immune system and occurs in different forms of endocytosis, including pinocytosis and receptor-mediated endocytosis, which deal with liquids and specific molecules respectively.