What is the function of a cell membrane?

A cell membrane protects the structures within the cell. Cell membranes are semipermeable, meaning that only certain objects are able to pass through them. Cell membranes also give shape to the cell and support its structure.

Proteins and lipids make up the composition of a cell membrane. There are three different types of proteins found within a cell membrane: structural protein, transport protein and glycoprotein. These support cell structure and shape, move molecules through the membrane and transmit signals between cells.

Cholesterol is a lipid found in cell membranes. This lipid is not found in plant cells. Glycolipids are also found in cell membranes. These have a carbohydrate component and help provide energy to cells.

Other structures found within a cell are the nucleus, mitochondria and chromosomes.