What chemical elements are included in the cell? The role and functions of chemical elements included in the cell. Presentation on biology on the topic "Chemical elements and their biological role in the body"

IN human organism Received 86. chemical elementsincluded in the periodic system of chemical elements D.I. Mendeleeva. These elements are conventionally divided into four groups:

• macroelements - elements that make up the bulk of the cell (approximately 98-99% in terms of dry mass), including carbon (C), hydrogen (H), oxygen (O) and nitrogen (N);
• elements whose content in the cell, in terms of dry mass, is about 1.9%. It is potassium (k), sodium (Na), calcium (CA), magnesium (Mg), sulfur (S), phosphorus (P), chlorine (CL) and iron (FE);
• elements, the content of which in the cell, in terms of dry mass, less than 0.01% - trace elements. This is zinc (zn), copper (Cu), fluorine (F), iodine (I), cobalt (CO), molybdenum (Mo), etc.
• elements, the content of which in the cell, in terms of dry weight, less than 0.00001% - ultramic-elements: gold (AU), uranium (U), radium (RA), etc.

The role of chemical elements in the cells of living organisms

Each element, which is part of a living organism, is responsible for performing a specific function (Table 1).

Table 1.Rol chemical elements in the cells of living organisms.

The lack of a item can lead to a disease, and even the death of the body, since each element plays a role. Macroelements of the first group form the basis of biopolymers - proteins, carbohydrates, nucleic acids, as well as lipids, without which life is impossible. The sulfur is part of some proteins, phosphorus - into the composition of nucleic acids, iron - into the composition of hemoglobin, and magnesium - chlorophyll. Calcium plays an important role in metabolism

A part of the chemical elements contained in the cell is part of inorganic substances - mineral salts and water. Mineral salts are in a cell, as a rule, in the form of cations (K +, Na +, Ca 2+, Mg 2+) and anions (HPO 4 2-, H 2 PO 4 -, Ci -, NSO 3 -), the ratio which determines the acidity of the medium important for the vital cells, so a weakly alkaline medium of many cells and its pH almost does not change, because it constantly supports a certain ratio of cations and anions.

Water plays a large role in chemical reactions occurring in a cage in aqueous solutions. It dissolves unnecessary organisms of metabolic products and thereby contributes to the derivation of them from the body. The large content of water in the cage gives it elasticity. Water contributes to the movement of various substances inside the cell or from the cell in the cell.

Examples of solving problems

Example 1.

Example 2.

Cells of living organisms in their chemical composition Significantly different from their surrounding inanimate media and in the structure of chemical compounds, and the set and content of chemical elements. In total, there are about 90 chemical elements in all living organisms, which, depending on their content, are divided into 3 main groups: macroelements , microelements and ultramicroelements .

Macroelements.

Macroelements In significant quantities are presented in living organisms, ranging from hundredths of percent to tens percent. If the content of any chemical in the body exceeds 0.005% of body weight, such a substance belongs to macroelements. They are part of the main fabrics: blood, bones and muscles. These include, for example, the following chemical elements: hydrogen, oxygen, carbon, nitrogen, phosphorus, sulfur, sodium, calcium, potassium, chlorine. Macroelements in the amount are about 99% of the mass of living cells, and most (98%) account for hydrogen, oxygen, carbon and nitrogen.

The table below shows the main macroelements in the body:

For all four elements common in living organisms (this is hydrogen, oxygen, carbon, nitrogen, as mentioned earlier) is characterized by one common property. These elements lack one or more electrons at an external orbit for the formation of stable electronic connections. Thus, the hydrogen atom for the formation of a stable electron communication lacks one electron at an external orbit, oxygen atoms, nitrogen and carbon - two, three and four electrons, respectively. In this regard, these chemical elements easily form covalent bonds due to the pairing of electrons, and can easily interact with each other, filling their external electronic shells. In addition, oxygen, carbon and nitrogen can form not only single, but also double bonds. As a result, the number of chemical compounds that can be formed from these elements are significantly increasing.

In addition, carbon, hydrogen and oxygen are the easiest among elements capable of forming covalent bonds. Therefore, they turned out to be the most appropriate for the formation of compounds that are part of living matter. It should be noted separately another important property of carbon atoms - the ability to form covalent bonds at once with four other carbon atoms. Thanks to this ability, frameworks from a huge number of various organic molecules are created.

Trace elements.

Although content trace elements does not exceed 0.005% for each separate elementAnd in the amount they constitute only about 1% of the mass of the cells, trace elements are necessary for the vital activity of organisms. In their absence or insufficient content, various diseases may occur. Many trace elements are part of non-peculiar groups of enzymes and are necessary for the implementation of their catalytic function.
For example, iron is part of HEMA, which is part of cytochromes, which are components of the electron transfer chain, and hemoglobin - protein, which provides oxygen transport from the lungs to the tissues. Iron deficiency in the human body causes anemia development. And the disadvantage of iodine, which is part of the thyroid hormone - thyroxine, leads to diseases associated with the insufficiency of this hormone, such as endemic goiter or cretinism.

Examples of trace elements are presented in the table below:

Ultramic-elements.

The group ultramicroelements It includes elements, the content of which in the body is extremely small (less than 10 -12%). These include bromine, gold, selenium, silver, vanadium and many other elements. Most of them are also necessary for the normal functioning of living organisms. For example, a lack of selenium can lead to cancerous diseases, and the lack of boron is the cause of certain diseases in plants. Many elements of this group also, as well as trace elements, are part of enzymes.

Organisms consist of cells. Cells of different organisms have a similar chemical composition. Table 1 presents the main chemical elements found in the cells of living organisms.

Table 1. The content of chemical elements in the cell

By content in the cell, three groups of elements can be distinguished. The first group includes oxygen, carbon, hydrogen and nitrogen. They account for almost 98% of the entire cell composition. The second group includes potassium, sodium, calcium, sulfur, phosphorus, magnesium, iron, chlorine. Their content in the cell is the tenth and hundredths of the percent. The elements of these two groups refer to macroelements (from Greek. macro - large).

The remaining elements representing the cells in cell and thousands of percentage shares are included in the third group. it microelements (from Greek. micro - Small).

No elements inherent in wildlife in the cell is not detected. All listed chemical elements are included in the composition of inanimate nature. This indicates unity of living and inanimate nature.

The lack of a item can lead to a disease, and even the death of the body, since each element plays a role. Macroelements of the first group form the basis of biopolymers - proteins, carbohydrates, nucleic acids, as well as lipids, without which life is impossible. The sulfur is part of some proteins, phosphorus - into the composition of nucleic acids, iron - into the composition of hemoglobin, and magnesium - chlorophyll. Calcium plays an important role in metabolism.

A part of the chemical elements contained in the cell is in accordance with the inorganic substances - mineral salts and water.

Mineral salts are in a cell, as a rule, in the form of cations (K +, Na +, Ca 2+, Mg 2+) and anions (HPO 2- / 4, H 2 PO - / 4, Ci -, NSO 3), whose ratio Determines the acidity of the medium important for vital cells.

(In many cells, the medium is low-alkaline and its pH almost does not change, since it constantly supports a certain ratio of cations and anions.)

From inorganic substances in wildlife, a huge role is played water.

Without water, life is impossible. It is a significant mass of most cells. Many water is contained in human brain cells and human embryos: more than 80% water; In the cells of adipose tissue - only 40.% To the old age, the water content in cells is reduced. A person who lost 20% of the water dies.

The unique properties of water determine its role in the body. It participates in heat regulation, which is due to the high heat capacity of water - consumption large number Energy when heated. What determines the high heat capacity of water?

In the water molecule, an oxygen atom is covalently associated with two hydrogen atoms. Polarna water molecule, since the oxygen atom has a partially negative charge, and each of the two hydrogen atoms has

Partially positive charge. Between the oxygen atom of one water molecule and the hydrogen atom, the other molecule forms a hydrogen bond. Hydrogen bonds provide a large number of water molecules. When water heated, a significant part of the energy is consumed on the gap of hydrogen bonds, which determines its high heat capacity.

Water - good solvent. Due to the polarity, its molecules interact with positively and negatively charged ions, thereby contributing to the dissolution of the substance. In relation to water, all substances of the cells are divided into hydrophilic and hydrophobic.

Hydrophilic (from Greek. hydro - Water I. fillet - I love) Call substances that dissolve in water. These include ionic compounds (for example, salts) and some non-ionic compounds (for example, sugar).

Hydrophobic (from Greek. hydro - Water I. phobos - Fear) Call substances insoluble in water. These include, for example, lipids.

Water plays a large role in chemical reactions occurring in a cage in aqueous solutions. It dissolves unnecessary organisms of metabolic products and thereby contributes to the derivation of them from the body. Great water content in the cage gives her elasticity. Water contributes to the movement of various substances inside the cell or from the cell in the cell.

The bodies of living and inanimate nature consist of the same chemical elements. The composition of living organisms includes inorganic substances - Water and mineral salts. The vital numerous functions of water in the cell are due to the peculiarities of its molecules: their polarity, the ability to form hydrogen bonds.

Inorganic cell components

In the cells of living organisms there are about 90 elements, and approximately 25 of almost all cells are detected. By content in the cell, the chemical elements are divided into three large groups: macroelements (99%), microelements (1%), ultramic-elements (less than 0.001%).

Macroelements include oxygen, carbon, hydrogen, phosphorus, potassium, sulfur, chlorine, calcium, magnesium, sodium, iron.
Microelems include manganese, copper, zinc, iodine, fluorine.
Ultramicroelements include silver, gold, bromine, selenium.

Organic cell components

Enzymes.

The most important feature of proteins is catalytic. Protein molecules that increase by several orders of chemical reactions in the cell are called enzymes. No one biochemical process In the body does not occur without the participation of enzymes.

Currently, over 2000 enzymes have been discovered. Their effectiveness is many times higher than the effectiveness of inorganic catalysts used in production. Thus, 1 mg of iron in the composition of the catalase enzyme replaces 10 tons of inorganic iron. Catalase increases the rate of decomposition of hydrogen peroxide (H 2 O 2) at 10 11 times. The enzyme catalyzing the reaction of the formation of coalic acid (CO 2 + H 2 O \u003d H 2 CO 3), accelerates the reaction of 10 7 times.

An important property of enzymes is the specificity of their action, each enzyme catalyzes only one or a small group of similar reactions.

The substance on which the enzyme affects is called substrate. The structures of the enzyme and substrate molecule must accurately match each other. This explains the specificity of enzymes. When connecting a substrate with an enzyme, the spatial structure of the enzyme changes.

The sequence of enzyme and substrate interaction can be portrayed schematically:

Substrate + Enzyme - Enzyme-Substrate Complex - Enzyme + Product.

From the scheme it can be seen that the substrate is connected to the enzyme with the formation of the enzyme-substrate complex. In this case, the substrate turns into a new substance - the product. At the end stage, the enzyme is released from the product and reincons again with the next substrate molecule.

Enzymes function only at a certain temperature, the concentration of substances, the acidity of the medium. Changes in conditions leads to a change in the tertiary and quaternary structure of the protein molecule, and, consequently, to the suppression of the activity of the enzyme. How does this happen? Only a certain section of the enzyme molecule, called the catalytic activity, has a catalytic activity. active center. The active center contains from 3 to 12 amino acid residues and is formed as a result of the bending of the polypeptide chain.

Under influence of different factors The structure of the enzyme molecule changes. At the same time, the spatial configuration of the active center is violated, and the enzyme loses its activity.

Enzymes are proteins that play the role of biological catalysts. Thanks to enzymes, several orders of magnitude increases the speed of chemical reactions in cells. An important property of enzymes is the specificity of action under certain conditions.

Nucleic acids.

Nucleic acids were from the indoor in the second half of the XIX century. Swiss biochemist F. Misher, who allocated a substance with a high content of nitrogen and phosphorus from the cell nuclei and called it "nucleic" (from lat. nuclease - core).

In nucleic acids, hereditary information on the structure and functioning of each cell and all living beings on Earth is stored. There are two types of nucleic acids - DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). Nucleic acids, as well as proteins, have species specificity, that is, the organisms of each type are inherent in its type of DNA. To find out the causes of species specificity, consider the structure of nucleic acids.

Nucleic acid molecules are very long chains consisting of many hundreds and even millions of nucleotides. Any nucleic acid contains only four types of nucleotides. The functions of nucleic acid molecules depend on their structure included in their composition of the nucleotides, their numbers in the chain and the compound sequence in the molecule.

Each nucleotide consists of three components: a nitrogenous base, carbohydrate and phosphoric acid. The composition of each nucleotide of DNA includes one of the four types of nitrogen bases (adenine - A, Timin - T, Guanin - G or cytosine - C), as well as the angle of water deoxyribosis and the residue of phosphoric acid.

Thus, DNA nucleotides differ only by the type of nitrogen base.

The DNA molecule consists of a huge set of nucleotides connected into a chain in a certain sequence. Each type of DNA molecule has the number characteristic of it and the sequence of nucleotides.

DNA molecules are very long. For example, for an alphabetic recording of the nucleotide sequence in DNA molecules from one human cell (46 chromosomes), a book of about 820000 pages would be required. The alternation of four types of nucleotides can form an infinite set of variants of DNA molecules. The specified features of the structure of DNA molecules allow them to keep a huge amount of information about all signs of organisms.

In 1953, the American biologist J. Watson and the English physicist F. Creek created a model of the structure of the DNA molecule. Scientists have established that each DNA molecule consists of two chains interconnected and spirally twisted. It has a kind of double helix. In each chain, four types of nucleotides alternate in a certain sequence.

The nucleotide composition of DNA differs from different species Bacteria, mushrooms, plants, animals. But it does not change with age, it depends little on changes ambient. Nucleotides Pairies, that is, the number of adenine nucleotides in any DNA molecule is equal to the number of thymidine nucleotides (AA), and the number of cytosine nucleotides is equal to the number of guanine nucleotides (C-g). This is due to the fact that the connection of two chains among themselves in the DNA molecule is subordinate specified ruleNamely: the adenine of one chain is always associated with two hydrogen bonds only with a thimine of another chain, and a guanine is three hydrogen bonds with a cytosine, that is, the nucleotide chains of one DNA molecule complementary, complement each other.

Nucleic acid molecules - DNA and RNA consist of nucleotides. The composition of DNA nucleotides includes a nitrogen base (A, T, G, C), the carbohydrate deoxyribosis and the residue of the phosphoric acid molecule. DNA molecule is a double helix consisting of two chains connected by hydrogen bonds on the principle of complementarity. DNA function - storage of hereditary information.

In the cells of all organisms there are ATP - adenosintrifosphoric acid molecules. ATP is a universal cell substance, whose molecule has rich communication energy. ATP molecule is one kind of nucleotide, which, like other nucleotides, consists of three components: a nitrogen base - adenine, carbohydrate - ribose, but instead of one contains three residues of phosphoric acid molecules (Fig. 12). Connections marked in the figure icon - rich in energy and are called macroeergic. Each ATP molecule contains two macroeergic ties.

When the macroeergic bond break and cleavage with the help of the enzymes of one phosphoric acid molecule, 40 kJ / mole of energy is released, and the ATP is converted into ADF - adenosine-phosphate acid. With the cleavage of another phosphoric acid molecule, another 40 kJ / mol is released; AMP is formed - adenosine monophosphoric acid. These reactions are reversible, that is, AMP can turn into ADP, ADP - in ATP.

ATP molecules not only split, but also synthesized, on this, their content in the cell is relatively constant. The value of ATP in the life of the cell is huge. These molecules play a leading role in the energy exchange, necessary to ensure the vital activity of the cell and the body as a whole.

RNA molecule, as a rule, is a single chain consisting of four types of nucleotides - a, y, g, ts. Three main types of RNA are known: IRNA, RRNA, TRNA. The content of RNA molecules in the cell is impermanent, they are involved in protein biosynthesis. ATP is a universal cell energy substance in which there are rich communication energy. ATP plays a central role in the exchange of energy in the cell. RNA and ATP are contained both in the kernel and in cytoplasm cells.

Tasks and tests on the topic "Theme 4." Chemical composition of the cell "."

• polymer, monomer;
• carbohydrate, monosaccharide, disaccharide, polysaccharide;
• lipid, fatty acid, glycerin;
• amino acid, peptide bond, protein;
• catalyst, enzyme, active center;
• nucleic acid, nucleotide.

Algorithm for solving problems.

Type 1. DNA self-copying.

One of the DNA chains has such a sequence of nucleotides:
Agtazgatztzgattatsg ...
What sequence of nucleotides has the second chain of the same molecule?

To write a sequence of nucleotides of the second chain of the DNA molecule, when the sequence of the first chain is known, it is enough to replace Timin on adenin, adenine to Timin, guanine-for cytosine and cytosin to guanine. By producing such a replacement, we get a sequence:
Tatstggztaghagtstaatg ...

Type 2. Protein coding.

The amino acid chain of the ribonuclease protein has the following beginning: lysine-glutamine-threonine-alanine-alanine-alanine-lysine ...
From which sequence of nucleotides begins the gene corresponding to this protein?

To do this, use the genetic code table. For each amino acid, we find its code designation in the form of the corresponding three nucleotides and write it down. Posing these three in each other in the same order, in which the corresponding amino acids corresponding to them, we obtain the formula for the structure of the information RNA section. As a rule, such triples are several, the choice is made according to your solution (but only one of the triples is taken). Decisions can respectively be several.
Ahatsaatsugzgzgzghaaga

From which sequence of amino acids begins the protein, if it is encoded by such a sequence of nucleotides:
Accentshatggzqgth ...

According to the principle of complementarity, we find the structure of the area of \u200b\u200binformation RNA formed on this section of the DNA molecule:
UGTSGGGUCHTSGGTSCA ...

Then we appeal to the genetic code table and for each top of the nucleotide, starting from the first, we find and write out the corresponding amino acid appropriate:
Cysteine-glycine-tyrosine-arginine proline -...

Ivanova T.V., Kalina GS, Software A.N. " General biology". Moscow," Enlightenment ", 2000

• Theme 4. "Chemical composition of the cell." §2-§7 p. 7-21
• Topic 5. "Photosynthesis." §16-17 p. 44-48
• Topic 6. "Cellular breathing." §12-13 p. 34-38
• Topic 7. "Genetic information." §14-15 p. 39-44

All living organisms, with the exception of viruses, consist of cells. Let's figure it out what it is and what is its structure.

What is a cell?

This is the main structural unit of living beings. She has its own metabolism. The cell may exist as an independent organism: an example of this is infusories, amoebs, chlamondonads, etc. This structure consists of various substances, both organic and inorganic. All cell chemicals play a specific feature in its structure and exchange.

Chemical elements

The cell includes about 70 different chemical elements, but the main of them are oxygen, carbon, hydrogen, potassium, phosphorus, nitrogen, sulfur, chlorine, sodium, magnesium, calcium, iron, zinc, copper. The first three are the basis of all organic compounds. All chemical cell elements play a role.

Oxygen

The amount of this element is 65-75 percent of the mass of the entire cell. It is part of almost all organic compounds, as well as water, this is due to its high content. This element performs a very important function in organisms cells: oxygen serves as an oxidizing agent in the process of cellular respiration, as a result of which the energy is synthesized.

Carbon

This element, like hydrogen, is contained in all organic substances. IN chemical composition Cells include it about 15-18 percent. Carbon in the form of CO takes part in regulation processes cellular functionsAlso, in the form of CO 2 participates in photosynthesis.

Hydrogen

This element in the cell contains approximately 8-10 percent. Its largest amount is in water molecules. Cells of some bacteria molecular hydrogen oxidizes for energy synthesis.

Potassium

The chemical composition of the cell includes about 0.15-0.4% of this chemical element. It performs a very important role, participating in the processes of generating a nervous impulse. That is why to strengthen nervous system It is recommended to use preparations with potassium content. Also, this element contributes to the maintenance of the membrane cell potential.

Phosphorus

The amount of this element as part of the cell is 0.2-1% of its total weight. It is part of ATP molecules, as well as some lipids. Phosphorus is present in the intercellular substance and in the cytoplasm in the form of ions. His big concentration is observed in the cells of muscle and bone tissue. In addition, inorganic compounds include this element are used by the cell for the synthesis of organic substances.

Nitrogen

This element is included in the chemical composition of the cell in the amount of 2-3%. It is contained in proteins, nucleic acids, amino acids and nucleotides.

Sulfur

It is part of many proteins, as it is contained in sulfur-containing amino acids. In the low concentration is present in the cytoplasm and the intercellular substance in the form of ions.

Chlorine

Contained in an amount of 0.05-0.1%. Supports cell electronically.

Sodium

This element is present in the composition of the cell in the amount of 0.02-0.03%. It performs the same functions as potassium, and also takes part in the processes of osmoregulation.

Calcium

The amount of this chemical element is 0.04-2%. Calcium is involved in the process of maintaining the membrane potential of the cell and exocytosis, that is, the allocation of certain substances from it (hormones, proteins, etc.) from it

Magnesium

The chemical composition of the cell includes 0.02-0.03% of this element. It takes part in the energy exchange and synthesis of DNA, is the component of enzymes, chlorophyll, is contained in ribosomes and mitochondria.

Iron

The amount of this element is 0.01-0.015%. However, in red blood cells it is much greater, as it is the basis of hemoglobin.

Zinc

It is contained in insulin, as well as in many enzymes.

Copper

This element is one of the component of oxidative enzymes that participate in the synthesis of cytochromes.

Proteins

These are the most complex compounds in the cell, the basic substances of which it consists. They consist of amino acids connected in a certain order into a chain, and then twisted in the ball, the form of which is specific for each type of protein. These substances perform many important functions in the vital cells of the cell. One of the most important is the enzymatic function. Proteins act as natural catalysts, accelerating the process of chemical reaction in hundreds of thousands of times - splitting and synthesis of any substances are impossible without them. Each type of enzymes participates only in one specific reaction and cannot enter the other. Also proteins are performed protective function. The substances of this group guarding the cell from foreign proteins from entering it are called antibodies. These substances are also protected from pathogenic viruses and bacteria the entire body as a whole. In addition, these compounds perform transport function. It lies in the fact that in the membranes there are proteins-conveyors that carry out or inside the cell certain substances. The plastic function of these substances is also very important. They are the main building materialFrom which the cell consists, its membranes and organelles. Sometimes proteins also carry out the energy function - with a lack of fats and carbohydrates, the cell splits these substances.

Lipids

This group of substances include fats and phospholipids. The first is the main source of energy. They can also accumulate as spare substances in case of fasting the body. The second serve the main component of cell membranes.

Carbohydrates

The most common substance of this group is glucose. It and similar, alone carbohydrates perform an energy function. Also, carbohydrates include polysaccharides, whose molecules consist of thousands of combined molecules - monosaccharides. They mainly perform a structural role, entering the membrane. The main polysaccharides of vegetable cells are starch and cellulose, animal - glycogen.

Nucleic acids

This group of chemical compounds includes DNA, RNA and ATP.

DNA

This substance performs the most important function - it is responsible for storing and hereditary genetic information. DNA is in kernel chromosomes. The macromolecules of this substance are formed from nucleotides, which, in turn, consist of a nitrogenous base represented by purines and pyrimidines, hydrocarbon and phosphoric acid residues. They are four species: adenyl, guanilla, thymidyl and cytidyl. The name of the nucleotide depends on which Purines are included in its composition, it may be adenine, guanine, thymine and cytosin. DNA molecule has the shape of two chains swam in the spiral.

RNA

This compound performs the function of implementing the information that is in DNA, through the protein synthesis, the composition of which is encrypted. This substance is very similar to the nucleic acid described above. Their essentials are that RNA consists of one chain, and not two. Also, the nucleotide RNA includes a nitrogenous base of uracil instead of thimine and ribose. Therefore, this substance is formed from such nucleotides as adenyl, guanilla, uridyl and cytidyl.

ATF

Any energy obtained by vegetable cells in the process of photosynthesis or animals due to the oxidation of fats and carbohydrates is ultimately stored in ATP, from which the cell receives it when it is necessary.

The biological role of chemical elements in the human body is extremely diverse.

The main function of macroelements consists in building tissues, maintaining the constancy of osmotic pressure, ionic and acid-base composition.

Microelements, entering the enzymes, hormones, vitamins, biologically active substances as complex renowners or activators, are involved in the exchange of substances, reproduction processes, tissue respiration, neutralizing toxic substances. Microelements actively affect the processes of blood formation, oxidation - restoration, permeability of vessels and tissues. Macro- and microelements - calcium, phosphorus, fluorine, iodine, aluminum, silicon - determine the formation of bone and dental fabrics.

It is evidence that the content of some elements in the human body changes with age. Thus, the content of cadmium in the kidneys and molybdenum in the liver to the old age increases. The maximum zinc content is observed during puberty, then it decreases and in old age reaches a minimum. Decreases with age and the content of other trace elements, such as vanadium and chromium.

Many diseases associated with the disadvantage or excess accumulation of various trace elements were revealed. Fluorine deficiency causes caries teeth, the deficit of the iodine is the endemic goiter, an excess of molybdenum is an endemic gout. Such regularities are associated with the fact that in the human body, the balance of optimal concentrations of biogenic elements is maintained - chemical homeostasis. Violation of this balance after

lack or excess element can lead to various diseases

In addition to six main macroelements - organohels - carbon, hydrogen, nitrogen, oxygen, sulfur and phosphorus, of which carbohydrates, fats, proteins and nucleic acids are required, for normal nutrition of man and animals, "inorganic" macroelements are needed - calcium, chlorine, magnesium, potassium , sodium - and trace elements - copper, fluorine, iodine, iron, molybdenum, zinc, and also, possibly (for animals it is proved), selenium, arsenic, chrome, nickel, silicon, tin, vanadium.

The disadvantage in the food diet of such elements such as iron, copper, fluorine, zinc, iodine, calcium, phosphorus, magnesium and some others leads to serious consequences for human health.

However, it is necessary to remember that the body is harmful not only the disadvantage, but also an excess of biogenic elements, since chemical homeostasis is violated. For example, when an excess of manganese with food in the plasma increases the level of copper (synergism of MP and SI), and in the kidneys it decreases (antagonism). Increasing the content of molybdenum in food products leads to an increase in the amount of copper in the liver. Excess zinc in food causes the oppression of the activity of iron-containing enzymes (2P and RE antagonism).

Mineral components that are vital in negligible, with higher concentrations become toxic.

The vital necessity, deficiency, the toxicity of the chemical element is presented in the form of the dependence curve "The concentration of the element in food products - the reaction of the body" (Fig. 5.5). Approximately horizontal portion of the curve (plateau) describes the area of \u200b\u200bconcentrations corresponding to optimal growth, health, playback. The big length of the plateau indicates not only the small toxicity of the element, but also on the greater ability of the body to adapt to significant changes in the content of this element. On the contrary, a narrow plateau indicates a significant toxicity of the element and a sharp transition from the required amount of quantity to life-threatening. When leaving the plateau (increasing the concentration of the trace element), all elements become toxic. Ultimately, a significant increase in the concentration of trace elements can lead to a fatal outcome.

A number of elements (silver, mercury, lead, cadmium, etc.)

machine toxic, as they get into the body already in microcolivities leads to severe pathological phenomena. The chemical mechanism of the toxic effects of some trace elements will be discussed below.

Biogenic elements were widely used in agriculture. Adding insignificant amounts of trace elements to the soil - boron, copper, manganese, zinc, cobalt, molybdenum - dramatically increases the yield of many cultures. It turns out that trace elements, increasing the activity of enzymes in plants, contribute to the synthesis of proteins, vitamins, nucleic acids, sugars and starch. Some of the chemical elements have a positive effect on photosynthesis, accelerate the growth and development of plants, the ripening of seeds. Microelements are added to animal feed to increase their productivity.

Widely used various elements and their compounds as medicines.

Thus, the study of the biological role of chemical elements, clarifying the relationship of the exchange of these elements and other biologically active substances - enzymes, hormones, vitamins - contributes to the creation of new drugs and the development of optimal modes of their dosing both with therapeutic and prophylactic purposes.