Free energy dissipation

Taking into consideration the main pressures channeling the evolution toward metabolic efficiency, that is, increasing free energy dissipation and energetic efficiency, one may single out... 

As to the mechanism explaining the evolutionary trend toward struc-turalization and therefore increased free energy dissipation and energetic efficiency, it still remains to be shown how the dynamic spatial order, so well described by Prigogine and so far the only principle that explains the biological order, became frozen in permanent biological structures. 

To characterize the system, in terms of state-independent properties, we need to impose initial and boundary conditions, as well as concentrations of nutrients, enzymes, metabolites, mRNA, temperature, and pressure. The state-dependent properties include rates of free energy dissipation, rates of heat production, nutrient uptake flows, and growth rates. System biology requires quantitative predictions on the degree of coupling, metabolic consequences of gene deletion, attenuation, and overexpression. 

As stated above, free-energy (C) dissipation does not imply that energy (t/) is dissipated it only implies that energy is (partly) transformed from free energy to pure heat, which equals the product of temperature and entropy. Consequently, the rate of free-energy dissipation is equal to the rate of entropy production multiplied by the absolute temperature. 

The so-called dissipation function () analyzes the rate of free energy dissipation in terms of the different processes in which free energy is dissipated. If, for instance, a chemical reaction occurs with a free-energy difference, AG, and at a rate, whereas at the same time a substance S flows from a space in which it has a high concentration to one where it has a low concentration, the rate at which the free energy is dissipated is ... 

It may be noted that we define AG such that it equals the chemical potential of the substrate minus the chemical potential of the product. We noted above that the possibility of free-energy dissipation drives a reaction. Free-energy differences like ACr and A/tg in the above equation embody such a possibility they act as forces that drive the reaction. Other examples are the contractile force on a muscle the voltage drop across an electrical resistance the osmotic pressure on a semipermeable membrane. The dissipation function consists of the sum of the products of fluxes (currents) and the (thermodynamic) forces that drive them [4]. 

The Irreversible Thermodynamics Model (Kedem and Katchalsky (1958)) is founded on coupled transport between solute and solvent and between the different driving forces. The entropy of the system increases and free energy is dissipated, where the free energy dissipation function may be written as a sum of solute and solvent fluxes multiplied by drivir forces. Lv is the hydrodynamic permeability of the membrane, AII v the osmotic pressure difference between membrane wall and permeate, Ls the solute permeability and cms the average solute concentration across the membrane. 

Heat generation, free energy dissipation, and growth. Energy balances, biocalorimetry, and monitoring of bioprocesses... 

The additional part of the free energy dissipation rate due to atomic jumps through the transformation boundary at the interface between ao and a phases is as follows ... 

The authors of [79] concluded that random electric noise generated by a free energy-dissipating process can do work. As long as the probability of the onset of a fluctuation is independent on the enzyme state, work is done. However, equilibrium noise is strongly state-dependent and consequently does not lead to work. ... 

Total deformation energy = Stored (Free) energy + Dissipated Energy... 

This equation shows that in isothennal biochemical reaction cycles, the entropy of the system changes because of the heat dissipation rate <(dis exchanged with the surrounding and the rate of free energy dissipation P due to entropy production. This equation also indicates the dissipative character of biochemical cycles. Dynamic equations similar to Eq. (11.5) can also be written for enthalpy and Gibbs ftee energy changes... 

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