The fluid mosaic model is a biological concept that describes the structure of cell membranes. It is composed of a lipid bilayer that is flexible and allows for the diffusion of molecules across the membrane. The model was proposed by S.J. Singer and Garth Nicolson in 1972, and since then, it has become a widely accepted theory in cell biology. There are several synonyms for the fluid mosaic model, including the membrane model, the lipid bilayer model, and the cell membrane model. Regardless of the name, the concept remains the same; the cell membrane is a flexible structure that allows for the movement of molecules in and out of the cell.