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The study of the chemistry of living processes has traditionally centered on the behavior of organic compounds in water; together they account for 99 per-cent of the matter in living systems. However, we also know that about 20 "inorganic" elements are also essential for life, and that they are found in similar amounts in most living systems. This book's objective is to examine and explain the importance of these elements. The authors begin with a survey of the chemical and physical factors controlling the elements of life. The essential functions of individual inorganic elements are then detailed. A final section consolidates a major theme of the book -- the cooperative interaction of elements in living systems. These chapters discuss the relationships between chemical activity and morphology and the effect that changes in the availability of elements have on life -- not only in providing evolutionary pressures but also in the context of the use of medicines and the spread of pollutants. This major graduate-level chemistry text provides a completely new way of looking at the chemistry of living processes. It is essential reading for all scientists interested in bioinorganic chemistry, including biologists, biochemists, chemists and physicists
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Preface
The majority of present-day living organisms require rather strict environmental conditions: temperature from 0 to about 40°C, pressure of the order of 1 atm., salinity up to about 4 per cent, pH in the range 4 to 9, redox potential in the region of stability of water (- 0.4 to + 0.8 V at pH= 7 versus the standard H+ /H 2 electrode), water activity between 0.7 and 1.0 mole fraction. In a few cases these limits can be greatly exceeded and it is known that, in the earth's past, conditions existed which were quite different from the present ones but did not hinder the development of life, although they did impose constraints upon the forms of life that could exist. Indeed, this is an essential feature oflife itself: the continuous adaptation ofliving organisms to changing environmental conditions through the development of defence devices and mechanisms against those changes, while sometimes turning new (adverse) factors into favourable ones. The result was, and still is, the survival and predominant proliferation of the fittest, and the history of evolution, which started as development under constraints of fixed conditions, became the history of the continuous adaptation of living organisms to changing conditions. In fact, and as we shall see, organisms themselves have caused much of the chemical environmental change. Although ideas concerning the evolution of species and forms are well accepted, they are less recognized when transferred to the small molecule chemistry scale, even though it has become customary to call 'chemical evolution' the series of events which is thought to have taken place between the beginnings of prebiotic synthesis of large organic molecules and the appearance of the first vesicles ('protocells') to which one might assign some 'vital' properties. Throughout the (unfinished) biological evolution there has been, in addition, a continual selection toward the best chemical components for the necessary functions and a continuous improvement in the conditions of their utilization, leading to the formation of separate compartments in cells, to the functional separation of cells, to the specialization of different multicellular organisms and to their diversification and development. As the species became more complex, so did their chemistry, as evidenced by the increased complexity ofthe materials used and the manipulation of dynamic factors. The development of materials is again well recognized in the evolution of biological polymers but it can only be thoroughly appreciated, we believe, in terms of the structures and patterns of the flow of