Physical models for the early evolution of cell membranes

Cells use lipid membranes to organize and define their chemical environments. All cell membranes are based on a common structure: bilayers composed of phospholipids with two hydrocarbon chains. How did biology converge on this particular solution for cellular encapsulation? The first cell membranes are proposed to have assembled from simple, single-chain lipids, such as fatty acids and their derivatives, which would have been available in the prebiotic environment. Here we argue that the physical properties of fatty acid membranes would have made them well suited for a role as primitive cell membranes and predisposed their evolution to modern, phospholipid-based membranes.