Final answer:
Lysosomes function to destroy ingested bacterial cells through the process of phagocytosis (option A), where hydrolytic enzymes digest the pathogen within a macrophage.
Step-by-step explanation:
The function of lysosomes in destroying ingested bacterial cells is phagocytosis. Lysosomes are part of the endomembrane system of animal cells and they facilitate the destruction of pathogens. The process begins when a macrophage, which is a type of white blood cell in the immune system, extends its plasma membrane to engulf a pathogen in a sequence known as phagocytosis.
Once the bacterium is enclosed within a vesicle inside the macrophage, this vesicle, called a phagosome, fuses with a lysosome forming a phagolysosome. The lysosome's hydrolytic enzymes break down and digest the pathogen effectively. The lysosome attacks the captured material, preventing disease by the invading bacteria. After the digestion process, the remains are expelled from the cell through exocytosis.