The Fluid Mosaic Model was proposed by S.J. Singer and Garth L. Nicolson. This model describes the structure of the plasma membrane of animal cells as a mosaic of components such as phospholipids, proteins, cholesterol, and carbohydrates.
Here are the key components of the plasma membrane according to the Fluid Mosaic Model:
- Phospholipids: These are the main fabric of the plasma membrane. Each phospholipid has a hydrophilic head pointing outside and a hydrophobic tail forming the inside of the bilayer.
- Cholesterol: It helps the plasma membrane to retain the fluidity. It is present between the phospholipids and prevents the compaction of hydrophilic tails at low temperatures and their expansion at high temperatures.
- Proteins: The plasma membrane has three types of proteins: Integral Proteins, Peripheral Proteins, and Glycoproteins.
- Carbohydrates: These are attached to proteins on the outside membrane layers.
The fluidity of the cell membrane is influenced by temperature, cholesterol, and the nature of fatty acids (saturated and unsaturated) in the phospholipids. The fluidity of the plasma membrane can also be restricted due to lipid rafts.