briefly explain fluid mosaic model.
The fluid mosaic model is an interpretation of cell membrane structure. It was proposed in the early 1970s by S.J. Singer and Garth Nicolson. The fluid mosaic model says that cell membranes are composed of a double layer of lipids with associated proteins. The lipid bilayer, as it is commonly referred to, has a back to back structure - in the outer layer the hydrophilic heads of the lipid molecules are oriented outward, and in the inner layer they are oriented inward.
A variety of proteins are attached to and embedded in the lipid bilayer. The attached, or peripheral, proteins include identifiers, hormone receptors, and immune proteins. The embedded proteins create transport passageways for the many different molecules that need to be moved into and out of the cell. The "fluid" part of the term comes from the belief that the proteins are able to flow and move around in the membrane.