fluid-mosaic model


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Fig. 162 Fluid-mosaic model . Cell membrane structure.

fluid-mosaic model

a hypothetical model of the structure of CELL MEMBRANES as observed with the ELECTRON MICROSCOPE, and proposed by Singer and Nicholson in 1972. The model proposes two phospholipid layers with proteins floating within the membrane like icebergs and sometimes projecting into the outer layer in a haphazard ‘mosaic’ pattern. See Fig. 162 . The membrane structure is not static: lipid molecules can move laterally and rotate on their axis (due to weak bonds between molecules) as can the protein molecules, although to a lesser extent. Some membrane proteins function as carriers in ACTIVE TRANSPORT and as cell ANTIGENS.