11 - Thermodynamics and biological systems

Abstract

This chapter analyzes biological processes using the basic tools of physics, chemistry, and thermodynamics. It provides a brief description of mitochondria and energy transduction in the mitochondrion. The study of proper pathways and multi-inflection points in bioenergetics are discussed. It also summarizes the concept of thermodynamic buffering caused by soluble enzymes and some important processes of bioenergetics using the linear nonequilibrium thermodynamics formulation. Biochemical reaction cyclic processes maintain the biological cell in a nonequilibrium state by controlling the influx of reactants and efflux of products. Biological systems do not decay toward an equilibrium state, but instead increase in size, developing organized structures and complexity. An evolved and adapted biological system converts energy in an efficient manner for the transport of substances across a cell membrane, the synthesis and assembly of proteins, muscular contraction, reproduction, and survival. The source of energy is adenosine triphosphate (ATP), which is produced by oxidative phosphorylation in the inner membrane of the mitochondria. Nonequilibrium thermodynamics formulations may provide a new approach of analyzing the results of experimental studies and guide the design of new experimental methods relating to biological energy conversions.