Early Membrane Models
	• Lipid bilayer structure was postulated early • Quantity of  lipid in red cell membrane would form a monolayer about twice the area of the cell surface • Electrical and permeability properties of membrane were similar to those of artificial lipid bilayers • Electron micrographs showed a sandwich-like structure with low electron density in the middle, high on the edges, about the width of two lipid molecules • Early models had proteins associating with polar surface groups of the bilayer