Plasma Membrane

Function Allows nutrients to pass into and out of the cell. Maintains homeostasis.

Structure Composed of a phospholipid bilayer called the fluid mosaic model.

Structure Structure of phospholipid bilayer: Each phospholipid contains a glycerol backbone, 2 fatty acid chains, and a phosphate group. A phosphate is formed by replacing one fatty acid in a lipid with a phosphate group.

Structure Structure of phospholipid bilayer: Each phosphate group has two fatty acid tails that are nonpolar and one head containing a polar phosphate group. The nonpolar tails stop water-soluble molecules form moving through the membrane. The polar head interacts with the watery environment inside and outside the cell.

Structure The phospholipid bilayer also contains: Cholesterol Transport Proteins Proteins Carbohydrates

Structure Function of cholesterol: Function of transport proteins: Stabilizes the membrane by preventing the fatty acid tails from sticking together. Function of transport proteins: Span the entire membrane to move substances through the plasma membrane.

Structure Function of carbohydrates: Stick out of the surface of the cell along with proteins in order to identify chemical signals. Function of proteins at inner surface: Attach the plasma membrane to the internal support structure of the cell. Give flexibility.