The appearance, ultrastructure and function of lysosomes.

Lysosomes are sacs containing digestive enzymes. They are created by the golgi apparatus.

Not to scale

The enzymes in the lysosomes have many important functions

• Digest material that phagocytic cells engulf: commonly this would mean digesting a pathogen that had been engulfed by a white blood cell.
• Digest old organelles (if left to build up they can be toxic)
• Digest old cells (autolysis)
• Release enzymes outside the cell so they can digest things externally (exocytosis)
• Digesting food that is delivered to the cell into useful components

When a lysosome has digested something, including waste products like old organelles, and useful chemicals are absorbed into the cytoplasm to be used again by the cell.