Vacuoles engulf entering energy-producing materials via endocytosis. Lysosomes attach to these organelles, fusing as enzymes digest the vacuole's contents. Lysosomes and vacuoles work together to form a digestive system for a eukaryotic cell.
Matter used in the production of energy – such as starches, fat and glycogen – enter the cell via endocytosis. Vacuoles form by this pinching-off process from the cell's outer membrane. When the vacuole envelops the matter, it becomes an endosome. Surrounded by its own cellular membrane, endosomes store cellular materials until they are ready for processing by lysosomes.
While the structure is produced by the Golgi body, the strong enzymes are produced by the endoplasmic reticulum. Approximately 50 different enzymes, known as acid hydrolases, break down proteins, genetic materials, polysaccharides, lipids and organelles in a process called autophagy. Lysosomes attach to the endosome, creating another lysosome where matter digests. Surrounding lysosomes is a layer of cellular membrane to protect the rest of the cell from their internal contents. When materials have sufficiently been digested, they diffuse through the lysosome membrane into the cytoplasm.
Genetic conditions such as Tay-Sachs disease can result in dysfunction of this disposal system. Due to a lack of an enzyme, the buildup of undigested macromolecules becomes detrimental to the nervous system and other organs.