Final answer:
The lysosome is the cell organelle responsible for engulfing and digesting bacteria. It destroys pathogens through a process called phagocytosis, using hydrolytic enzymes within a phagolysosome.
Step-by-step explanation:
The part of a cell that engulfs and digests bacteria is the lysosome. Lysosomes are membrane-bound organelles containing hydrolytic enzymes that play a crucial role in a variety of cell processes, including the destruction of pathogens through a process known as phagocytosis.
When a cell, such as a macrophage, encounters a bacterium, it extends parts of its plasma membrane to enclose the bacterium creating a vesicle known as a phagosome. The phagosome then fuses with a lysosome, forming a phagolysosome, where enzymes and acids from the lysosome degrade and digest the bacteria, effectively destroying the pathogen.