Modification of membrane lipids. Phenethyl alcohol-induced alteration of lipid composition in Tetrahymena membranes

Direct measurement of the partition coefficient of $\text{n-}\text{hexane}$ into phosphatidylcholine and phosphatidylcholine-cholesterol bilayers showed that (a) isotropic liquids are not good models for lipid bilayers and (b), Regular Solution Theory cannot, in general, be applied to lipid bilayer membranes at temperatures above their phase transition. Theoretical and experimental evidence is given.