Order in living systems

We shall see many examples of the creation of order in living systems as we move forward. Life is utterly and completely dependent on such order, both in structure and function. 

The importance of the liquid crystal order in living systems and in model substances is well documented. The lyotropic mesomorphism usually observed in these systems is generally related to the presence of amphiphilic moieties embedded in an intrinsically chiral environment that may cause chiral smectic or, more frequently, cholesteric states. However, any comment on this special area is outside the scope of the present paper,... 

According to Stuart Kauffman, self-organisation processes initiate a trend which leads to more complex states of the system. In living systems, there are two forces which determine order (Kauffman, 1995) ... 

Given a NO/3NO- couple potential of 0.39 V, the effecter molecule of NOS would thus be expected to be ONOO, not NO. However, the direct detection of NO in living systems by a number of techniques (17,18,26) as well as the observation that activation of NOS results in antioxidant chemistry [briefly reviewed in (160-162)] suggest otherwise. The definitive mediation of vascular tone by NO (18, 31) and the discrete effects of HNO and NO donors observed in vitro, in vivo, and ex vivo corroborate the implications that NO cannot be readily reduced to NO- under physiological conditions (147). Additionally, the oxidation of methyl viologen by O2 was determined to be two orders of magnitude... 

Morovitz, H. (1955). Some Order- Disorder- Considerations in Living Systems. Bull.Math.Bio-phys., 17,81-86. 

Chemical reactions in living systems involve orderly release, storage, or utilization of energy. Knowledge of thermodynamics and kinetics is essential to appreciate how this occurs. Thermodynamics deals with the changes in energy content between reactants and products, whereas kinetics is concerned with the reaction rates. 

Morovitz, H. (1955) Some order-disorder considerations in living systems. Bull Math. Biophys., 17, 81-86. 

The total number of proteins found in nature is extremely large. The 1992 edition of the Enzyme List (Webb, 1992) lists 3196 enzymes. The total number of proteins in a eukaryotic cell has been estimated to be between 10,000 and 20,000 (Alberts et al., 1989), based upon the number of different messenger RNAs in a typical eukaryotic cell. This number does not reflect the thousands of natural mutants of any one protein that may occur. (Approximately 500 naturally occurring mutants of human hemoglobin have been identified to date.) Nor does it take into account the fact that there are often very substantial differences in homologous proteins that perform the same function in different species. A minimal estimate of the number of different proteins in living systems on earth would be on the order of 10,000 x 500 X the number of species i.e., literally, billions. 

Many reactions are catalysed by acids. Hydrolysis of esters and the reverse reaction, esterification, are important examples both in the laboratory and in living systems (reaction 5.38). In the forward direction, the initial rate is proportional to [H30 + ][71] in the reverse direction the kinetic dependence is on [H30+][74][Et0H]. By the principle of microscopic reversibility (Chapter 1), the reaction must have the same mechanism in both directions. The third-order kinetic dependence of... 

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