The Chemical Elements of Life

Of the 117 elements currently known, relatively few are essential to living systems. Actually, only six nomnetallic elements form the building blocks of cells C, H, O, N, P, and S. They are the constituent elements of proteins, nncleic acids, and carbohydrates. Although the natural abundance of carbon is qrrite low (aborrt 0.1 percerrt by mass of Earth s crust), it is present in nearly all biological 

The metals play several different roles in hving systems. As cations (Na, K, Ca, and Mg ), they serve to maintain the balance between intracellular and extracellular fluids, nerve transmissions, and other activities. They ate also needed for protein functions. For example, the Fe ion binds oxygen in hemoglobin molecules and Cu, Zn, and Mg ions are essential for enzyme activity. In addition, calcium in the form of Ca5(P04)3(OH) and Ca3(P04)2 is an essential component of teeth and bones. 

The periodic table shown highlights the essential elements in the human body. Of special interest are the trace elements, such as iron (Fe), copper (Cu), zinc (Zn), iodine (I), cobalt (Co), selenium (Se), and fluorine (F), which together make up about 0.1 percent of the body s mass. Although the trace elements are present in veiy small amounts, they are cmdal for our health. In many cases, however, their exact biological role is still not fiilly understood. 

These elements are necessary for biological functions such as growth, the transport of oxygen for metabolism, and defense against disease. There is a delicate balance in the amounts of these elements in our bodies. Too much or too little over an extended period of time can lead to serious illness, retardation, or even death. 

1 Which of the foUowitig elements would you expect to have chemical properties most similar to those of S  

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The Chemical Elements of Life Radioactive Bone 265 The Power of Radicals 298 Why Is Carbon Monoxide Toxic ... 

A very readable paper which develops and enlarges the theme of this paragraph is The Chemical Elements of Life by R. J. P. Williams, J. Chem. Soc., Dalton Trans. (1991) 539. 

The cycling of the element Ccirbon depends primarily on its chemical properties. Like nitrogen and sulfur, but unlike phosphorus, silica, and iron, carbon forms volatile, soluble, and insoluble compounds and can thus circulate through the atmosphere, hydrosphere and lithosphere. Since carbon is the basic element of life its circulation through the biosphere is of particular importance. 

To form the chemical basis of life, an element ought to be able to form large and complex molecular structures, including branched rings and chains. It would be simplest if the element were able to do this by bonding to itself. 

Chemicals are the basic elements of life and the world around us. Chemical products fill our homes. Materials made from chemicals are found in cars, clothing, furniture, tools, food, and other things we use and contact daily. Most chemicals are not dangerous. Many chemicals and compounds are beneficial. Some are dangerous and may cause harm. There are many factors involved in deciding about risks related to chemicals. This chapter explores information for determining risks and preventing harm. 

Lining up these five balances with the elemental profiles of different geothermal hot spots, the chemicals outside at hot springs match the chemicals inside of life better than seawater does. In particular, the hot springs are rich in potassium, phosphate, and zinc and (relatively) poor in sodium. On each of these four counts, hot springs are close to the inside of cells in ways that seawater is not. 

Oxygen is the most abundant element on earth The earths crust is rich in carbonate and sili cate rocks the oceans are almost entirely water and oxygen constitutes almost one fifth of the air we breathe Carbon ranks only fourteenth among the elements in natural abundance but trails only hydro gen and oxygen in its abundance in the human body It IS the chemical properties of carbon that make it uniquely suitable as the raw material forthe building blocks of life Let s find out more about those chemi cal properties... 

The elemental composition of the fish otoliths is a potential source of the useful information to recreate environment history of the individual fish in some of the species. In-depth study of the chemical composition of the otolith center (formed eaidy in fish life) and otolith edge (formed later in fish life) ensures chronological and environmental information stored in the otoliths [1]. This infoiTnation may be achieved by X-ray electron probe microanalysis (EPMA). EPMA is the analytical method to determine the elemental composition of different otolith s parts, their sizes varying from ten up to some tens of microns. 

Mason, B. and Moore, C.B. (1982). Principles of Geochemistry (4th ed.). Wiley, New York Press, F.S. and Siever, R. (1986). Earth (4th ed.). W.H. Freeman and Company, New York Stanley, S.M. (2002). Earth System History. W.H. Freeman and Company, New York Wayne, R.P. (2002). Chemistry of Atmospheres (3rd ed.). Oxford University Press, Oxford Williams, R. J.P. and Frausto da Silva, J.J.R. (1996). The Natural Selection of the Chemical Elements - The Environment and Life s Chemistry. Clarendon Press, Oxford... 

Williams, R.J.P. and Frausto da Silva, J.J.R. (1996). The Natural Selection of the Chemical Elements - The Environment and Life s Chemistry. Clarendon Press, Oxford... 

The interstellar medium is thus a chemically diverse medium fed nearly all of the chemical elements by supernova explosions. Conditions in the interstellar medium produce a cocktail of molecules that ultimately find themselves back on the surface of planets during the formation of the new star and solar system. Does the interstellar medium seed life with molecules from space The nature of interstellar medium chemistry might then add credibility to the formation of life in many places within the Universe and act as a panspermia model for the origins of life. 

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