Fluid mosaic model of plasma membrane was given by Singer and Nicholson in year $1972$ . The biological membrane are considered to be a quasified structure in which the lipids and integral proteins are arranged in a mosaic manner.
Gorter and Grantal measured the lipid content of haemolyzed eythrocytes and concluded that cell membrane are chiefly formed of phospholipids arranged to form a bimolecular lipid sheet.