Abstract
To describe the lateral phase separation in biological membranes, we propose phenomenological models for binary and ternary lipid mixtures. We consider a coupling between the local lipid composition and internal membrane structure, and its influence on transitions between liquid and gel membrane phases. Assuming that the gel transition temperature of a pure lipid is shifted by the presence of other lipids, we obtained a variety of binary phase diagrams which are in semi-quantitative agreement with the experiments. With the use of the model parameters deduced from the binary cases, we predict the quantitative phase behaviour of the ternary lipid systems.