Energetics of Biological Systems

Living biological systems are metabolically active, open systems that constantly exchange matter and energy with their environment. At the core of this lies cellular metabolism, an interconnected network of chemical reactions that transforms environmental nutrients into the mass and free energy that supports homeostasis, growth, and development. Because the matter and energy fluxes sustained by metabolism keep cells far from thermodynamic equilibrium, it has long been speculated that energy dissipation poses essential constraints to cellular growth, homeostasis, and organismal development. Here, I will discuss our findings using a data-driven approach to infer unicellular microbial thermodynamics across life's domains by parsing existing data from more than 400 instances of balanced unicellular growth and analyzing them using a minimal non-equilibrium thermodynamics framework. I will elaborate on combining this framework with calorimetric heat dissipation measurements, perturbations, imaging, and metabolomics to determine the energetics driving mammalian cell growth and metazoan embryonic development.