Lysosomes serve as storage vesicles for the hydrolytic enzymes that digest materials taken into the cell via endocytosis. Produced by the Golgi apparatus, lysosomes have single-layered membranes that are impermeable to the enzymes they contain and resistant to the enzymes' digestive action. Ordinarily, lysosomes only release their enzymes when they come into contact with endocytic vesicles, for, if they were to release their enzymes into the cytoplasm directly, the enzymes would digest the cell itself.
