Chemistry and physics of primitive membranes

A membrane boundary structure was essential for the advent of cellular life. The membranes of contemporary cells are composed of a mosaic of proteins embedded in a bimolecular layer of phospholipids, each of which requires a complex enzymatic pathway for its synthesis. The earliest forms of life could not have had such a highly evolved pathway in place. Amphiphilic monocarboxylic acids are present in carbonaceous meteorites and can be synthesized under simulated geochemical conditions. Such compounds have physical and chemical properties that allow them to assemble into bilayer membranes and are therefore plausible components of the first cellular membranes.