Turnstiles and bifurcators: The disequilibrium converting engines that put metabolism on the road

► A model for the origin of life is discussed in thermodynamic and geochemical terms. ► Its geochemical basis is the alkaline vent, serpentinization, Hadean ocean model. ► Its thermodynamic approach is framed in terms of non-equilibrium thermodynamics. ► It emphasizes processes of free energy conversion and their mechanistic requirements. ► Living systems are seen as a network of disequilibria linked in driver-driven pairs.