(Campbell and Reese, 2002)
Episode 8 - Lysosomes
Lysosomes are a special type of vesicle, which contains hydrolytic enzymes that work best in the acidic medium enclosed by the lysosome membrane. The lysosome is the main organelle of the intracellular digestion of organic compounds; their enzymes can hydrolyze nearly all polysaccharides, proteins, nucleic acids, and some lipids. The products of digestion, like monosaccharides, amino acids, and other monomers are transported into the cytosol and become available for assimilation by the cell. Lysosomes may even digest entire cells or cell parts, once those parts become damaged or prove no longer functional, to recycle nutrients in the cell (Autophagy). Thus, lysosomes allow the cell to continually renew itself.
(Campbell and Reese, 2002)
Lysosome enzymes and membrane are first created in the Rough ER, transported to the Golgi for final touch-ups, and then are budded from the ends of the Golgi body of animal and fungi cells. They often fuse with transport vesicles formed at the cell membrane, to digest the food particles or bacteria that was brought in by endocytosis or phagocytosis.
TEM image of a lysosome of a human eosinophilic granulocyte (Source: Mader, 2007).
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