A Macroscopic Quantum Heat Engine: Nested Resonant Structures and the Entropic Stability of Life

Biological systems are fundamentally containers of thermally fluctuating atoms that through unknown mechanisms are structurally layered across many thermal scales from atoms to amino acids to primary, secondary, and tertiary structures to functional proteins to functional macromolecular assemblies and up. Understanding how chemical thermodynamics sc ales across these layered structures is central to describing biological structure and function. Muscle - with chemical thermodynamics well-defined on two different thermal scales - provides a clear solution to this problem. In 1938, A.V. Hill made the extraordinary observation that the mechanics and chemistry of muscle contraction is defined independent of the structural components of muscle, implying that the mechanics and chemistry of myosin motor proteins within muscle do not classically scale up to muscle. We have demonstrated experimentally that thermal scaling bridges Hills top-down thermodynamics and the bottom-up philosophy of molecular biologists. That is, with thermal scaling N individual myosin motor switches physically collapse into an ensemble of N myosin motor switches creating a functional entropy within the ensemble well defined by the statistical mechanics of a binary system of switches. This ensemble entropy stabilizes the resonant ensemble structure of muscle and energetically drives the irreversible kinetics and energetics of muscle contraction. Here I develop a general model of thermal scaling and show that it occurs when the ensemble state of a system is defined, at which point the number of ways constituent molecules can account for the ensemble state contributes to the entropy of the ensemble state. At that point, the statistical occupancy of molecular states physically replaces the physical occupancy of molecular states. This is not a classical mechanism and as shown here results in many quantum-like phenomena, which consistent with Hills observation means that biological function cannot be described by classical molecular mechanisms.