Chapter 15 - Living Systems

Abstract

This chapter discusses membrane transport and biochemical oscillators' relation with living state. Living systems are characterized by a high structural order and ordered behavior in space and time. There appears to be a contradiction between the increasing complexity in the course of biological development and the second law of thermodynamics. However, it may be noted that a living system is an open system whose entropy may increase or decrease. Living systems are constantly exchanging matter and energy with the environment. In view of the complexity in biological systems, different theoretical techniques have to be applied for different non-equilibrium regions. The range of applicability of linear thermodynamics of irreversible processes is quite limited on account of very thin membranes, nano-pores, and large size of bio-molecules. However, the physical concepts of fluxes and forces are still useful for the non-linear region for comprehending the basic features of non-equilibrium phenomena. Fluxes can be non-linear. Beyond non-linear steadystate range, non-linear dynamics as well as non-linear kinetics can be applied profitably for investigating the far from equilibrium phenomena, using the concepts based on the corresponding studies of physico-chemical phenomena.