Entropy and life

A. Kleidon and R. D. Lorenz (eds.), Non-equilibrium Thermodynamics and the Production of Entropy Life, Earth, and Beyond, Springer, Berlin, 2005. 

As far as chemistry and life sciences are concerned, there are for me and many others two main reasons for this fascination, summarized in Figure 9.4 firstly, above a certain critical concentration, structural order is achieved starting from the chaotic mixture of disordered surfactant molecules. As discussed earlier, this increase of order is attended by an increase of entropy and a decrease of free energy. 

Since Ao, the area of the molecule in the surface, is roughly equal to the collision area, 4irr, we can say that if the simple gas collision formula (i) applies to the surface reaction, and that if the entropies and energies of activation of the two types of reaction are the same, their half-life times should be equal. This does not necessarily mean that the actual rates are equal these are given by (ii) and (iii), and are simply functions of the concentrations n, and rib. For these bimolecular reactions the bulk reaction will allow more molecules to react per second than will the surface reaction. 

Of course, life is not just a question of chemicals. Tlierefore, as stated, we will also discuss topics that are equally relevant, but on which misunderstandings and differences of opinion persist, such as the question of the quality of energy and its usefulness in achieving a possible optimal cyclic steady state the confusion around the concept of entropy and the applicability of the second law of thermodynamics to... 

Changes of entropy are occuring all around us, but for most of us, like M. Jourdain with his prose, awareness can come quite late in life. Although we cannot detect these changes with our physical senses, it is possible to calculate them from simple measurements. After defining entropy, and performing such calculations, the concept will become progressively more familiar. 

Another Way of Looking at Entropy, by Daniel Hershey in Chemical Engineering Education (1989, summer, p. 154), discusses entropy and aging. Write an expression for entropy production in the hnman body that is consistent with the following statement by Hershey The internal entropy production in living systems is a consequence of several irreversible chemical reactions which constitute the chemistry of life. ... 

Gladyshew. G.P. On thermodynamics, entropy and evolution of biological systems What is life from a physical chemist s viewpoint. Entropy 1999. L 9-20. 

Russell MJ The alkaline solution to the emergence of life Energy, entropy and early evolution. Acta Biotheoretica 2007, 55(2) 133—179. 

Shimokawa, S. Ozawa, H. (2005). Thermodynamics of the Ocean Circulation A Global Perspactive on the Ocean System and Living Systems. In Non-equilibrium thermodynamics and die production cf entropy life, earth and beyond, A. Kleidon, R. 

It is important to imderline these facts, because every transformation between energy and matter needs a catalisys through an information system, to increase the neg-entropy and to proceed toward ordered forms. We know that the exchanges energy-matter-information, which allowed the emergence of life on Earth, are of the maximum importance and changed completely the evolution of the entire Planet. A mutual interaction and an information... 

Earlier in this chapter, we saw that it is possible for a reaction to exhibit a decrease in entropy and still be spontaneous if and only if the entropy of the surroundings increases such that AS,o, for the process is positive. In other words, we have to take the whole picture into account when determining if a process will be spontaneous. Yes, it is true that many of the reactions employed by life are not spontaneous by themselves. But when they are coupled with other highly favorable reactions, such as the metabolism of food, the total entropy (system plus surroundings) does actually increase. As an example, consider the metabolism of glucose ... 

As is developed in Chapter 5 (Regulation of Protein Biosynthesis), this theorem states that the continued synthesis and degradation of proteins and enzymes constitutes the life process by enabling the metabolic network to achieve negative entropy and remain in a far-from-equilibrium condition. 

The protein synthetic mechanism is the fundamental project of life and is thus the embodiment of the life process. The continued synthesis and degradation of proteins and enzymes maintains the metabolic network in a state of negative entropy, so that all reactions occur under far-from-equilibrium conditions. This nonequilibrium state, in a sense, constitutes the life process. Enzymes are the functional entities of the life process, and, in accordance with the principle of nonequilibrium thermodynamics (see Chapter 2), semistable enzymes constitute the functional basis of life. A totally stable enzyme (denatured enzyme) is inert, having no catalytic function, and is incapable of interacting with its substrates and products. An unstable enzyme has too transient an existence to carry out a catalytic reaction in a steady-state network. Yet for catalytic action to persist for a sufficient time, there must be a certain degree of stability, and the catalytic function of an enzyme requires flexibility or conformity. It is in this sense that enzymes can be considered as semistable. 

Real Life Processes and Entropy Irreversible Processes... 

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