Thermodynamic Bounds Based on Time-Reversal Asymmetry in Living Systems: A Conceptual Framework for Molecular Motors

The three laws of thermodynamics (plus the zeroth) describe equilibrium and near-equilibrium systems but inadequately capture the far-from-equilibrium dynamics of living systems, characterized by active energy consumption, internal set points, and feedback mechanisms. This conceptual paper proposes a thermodynamic bound tailored to living systems: In living systems with internal set points and feedback control, the housekeeping entropy production rate $\Sigma_{hk}$ is bounded below by a function of time-reversal asymmetry $\Lambda$, ensuring biological stability and functionality: $\Sigma_{hk} \geq f(\Lambda)$, where $f$ incorporates thermodynamic uncertainty relations, information-theoretic measures, and information flow costs. We derive this rigorously using stochastic thermodynamics integrated with feedback control, support it with equations, analytical derivations, Python simulations of a kinesin motor model using real parameters, sensitivity analysis, Bayesian inference, uncertainty quantification, null model comparisons, and falsifiability. The framework draws on empirical data from actin cortex studies and recent research on kinesin thermodynamics, kinesin-8 and kinesin-14 specifics including their structures and roles in meiosis, kinesin-5's role in meiotic spindle bipolarity, the role of dynein in meiotic division including its structure, and thermodynamic laws in living cells, substantiated by peer-reviewed references from prestigious journals.