Fluid mosaic model

Fluid mosaic model was proposed in 1972 by S. Jonathan Singer and Garth L. Nicholson. It is a widely accepted model to explain the structural and physiological nature of the cell membrane. The model states that (1) Membranes are formed from both lipids and proteins and (2) Membrane proteins are of two types: peripheral protein and integral protein. The structure-forming unit is a lipid bilayer. Integral proteins are buried in the bilayer and peripheral proteins are attached on the surface.

Peripheral proteins are one that are loosely connected to the membrane surface and can be easily removed by mild treatment. They makes up 20 to 30 % of total membrane protein and are soluble in aqueous solutions. Integral proteins are buried in the lipid and they makes up 70 to 80 % of membrane protein. They can’t be extracted easily from the membrane and are insoluble in aqueous solutions. They are amphipathic in nature; with hydrophobic region buried in the lipid and hydrophilic region projects from the membrane surface.