Lysosome: Definition & Function

Definition of Lysosome

Has anyone ever asked you to take out the trash? You probably did not consider that action as part of a team effort, but in a cell, it is. Inside a cell, numerous organelles function to remove wastes. One of the key organelles involved in digestion and waste removal is the lysosome. Lysosomes are organelles that contain digestive enzymes. They digest excess or worn out organelles, food particles, and engulfed viruses or bacteria. Lysosomes are like the stomach of the cell.

Structure of Lysosomes

Lysosomes are surrounded by a membrane composed of phospholipids that separate the inside of the lysosomes from the membrane’s external environment. Phospholipids are the same cellular molecules that make up the cell membrane surrounding the entire cell. Lysosomes range in size from 0.1 to 1.2 micrometers. Structurally, lysosomes are like a floating garbage bag that contains enzymes capable of digesting molecules. Their external membrane is like a gateway that allows molecules inside of the lysosome without allowing the digestive enzymes to escape into the cell.

Function

Cells produce waste like all living things. The lysosomes are the garbage disposals of the cell. When a part of the cell becomes damaged or obsolete, it is moved to the outer edge of the lysosome. The membrane of the lysosome opens and the molecule is moved into the lysosome. Once inside, the digestive enzymes produced by the lysosome break down the molecule. After it is has been completely broken down, the lysosome opens to release the remains back into the cell in the form of a vesicle that the cell can expel through its membrane. The final remains are much more compact and easier for the cell to manage than the original molecule. This process is also the same for invaders of the cell, such as bacteria and other foreign matter.