Biochemistry

CHAPTER 1. BIOCHEMICAL CHARACTERISTICS OF LIVING ORGANISMS 1.1 CHEMICAL COMPOSITION OF A HUMAN BODY In the organisms that inhabit our planet, more than 60 chemical elements of the Periodic Table of D.I. Mendeleev are found, however, only about 30 elements are constantly found in their composition. The chemical elements that make up the basis of living matter are called biogenic or organogenic. Among the biogenic chemical elements, approximately half are metals'. Na, K, Ca, Ba, Mg, Zn, Fe, Mn, Cu, Co, Mo, Cr, Li, Ni, V; they are figuratively called the "metals of life." Non-metal biogenic elements are C, N, H, O, S, P, B, Se, Si, Cl, F, I, Br. Other elements found in wildlife arc intermittent and their biological role is not entirely clear. According to the content in living matter, a group of macroelements is isolated, the concentration of which exceeds 0.001%: О, С, H, Ca, N, P, S, Mg, K, Na, Cl, Fe. The group of microelements consists of such chemical elements, which account for less than 0.001%: Mn, Zn, Cu, B, Co, and others. Ultramicroelements are contained in even smaller amounts. The content of elements in living matter, in general, is proportional to the composition of the living environment of organisms, adjusted for the biological value of chemical elements and, therefore, the need for them in organisms. The bulk of the biosphere is made up of just such chemical elements - with a small atomic mass, forming gaseous and readily soluble compounds in water (С, О, H, N, P, S). These elements account for more than 98% of the biomass of the organisms of our planet. Another important property of widespread biogenic elements is their ability to form multiple chemical bonds. And this, in turn, significantly increases the number of various chemical compounds that form living matter. Two chemical elements of this group - phosphorus and sulfur - are able to form compounds rich in energy. The decomposition of such compounds is accompanied by the release of a large amount of energy, and their synthesis by its absorption. Among nutrients carbon is one of the most important; life on our planet has a carbon base. Unlike all other chemical elements, carbon atoms can be connected by various bonds (single, double, triple) both among themselves and with the atoms of many other elements, thus forming carbon chains of theoretically any length. These chains are able to branch, as well as lock into rings of various structures and sizes. 7