Every science is full of concepts, and if these concepts are not mastered, or indirect topics can be very difficult to learn. One of the concepts that should be well understood by every person who considers himself more or less educated is the division of materials into organic and inorganic. It doesn’t matter how old a person is, these concepts are on the list of those with the help of which they determine the general level of development at any stage of human life. In order to understand the differences between these two terms, you first need to find out what each of them is.

Organic compounds - what are they?

Organic substances are a group of chemical compounds with a heterogeneous structure, which include carbon elements, covalently linked to each other. The exceptions are carbides, coal, and carboxylic acids. Also, one of the constituent substances, in addition to carbon, are the elements of hydrogen, oxygen, nitrogen, sulfur, phosphorus, and halogen.

Such compounds are formed due to the ability of carbon atoms to form single, double and triple bonds.

The habitat of organic compounds is living beings. They can be either part of living beings or appear as a result of their vital activities (milk, sugar).

The products of the synthesis of organic substances are food, medicine, clothing items, building materials, various equipment, explosives, various types of mineral fertilizers, polymers, food additives, cosmetics and more.

Inorganic substances - what are they?

Inorganic substances are a group of chemical compounds that do not contain the elements carbon, hydrogen or chemical compounds whose constituent element is carbon. Both organic and inorganic are components of cells. The first in the form of life-giving elements, others in the composition of water, minerals and acids, as well as gases.

What do organic and inorganic substances have in common?

What could be common between two seemingly antonymous concepts? It turns out that they have something in common, namely:

1. Substances of both organic and inorganic origin are composed of molecules.
2. Organic and inorganic substances can be obtained as a result of a certain chemical reaction.

Organic and inorganic substances - what is the difference

1. Organic ones are better known and studied scientifically.
2. There are much more organic substances in the world. The number of organic ones known to science is about a million, inorganic – hundreds of thousands.
3. Most organic compounds are linked to each other using the covalent nature of the compound; inorganic compounds can be linked to each other using an ionic compound.
4. There is also a difference in the composition of the incoming elements. Organic substances consist of carbon, hydrogen, oxygen, and less commonly nitrogen, phosphorus, sulfur and halogen elements. Inorganic - consist of all elements of the periodic table, except carbon and hydrogen.
5. Organic substances are much more susceptible to the influence of hot temperatures and can be destroyed even at low temperatures. Most inorganic ones are less prone to the effects of extreme heat due to the nature of the type of molecular compound.
6. Organic substances are the constituent elements of the living part of the world (biosphere), inorganic substances are the nonliving parts (hydrosphere, lithosphere and atmosphere).
7. The composition of organic substances is more complex in structure than the composition of inorganic substances.
8. Organic substances are distinguished by a wide variety of possibilities for chemical transformations and reactions.
9. Due to the covalent type of bond between organic compounds, chemical reactions last slightly longer than chemical reactions in inorganic compounds.
10. Inorganic substances cannot be a food product for living beings; even moreover, some of this type of combination can be deadly to a living organism. Organic substances are a product produced by living nature, as well as an element of the structure of living organisms.

Our entire world: plants, fauna, everything that surrounds us, consists of the same microelements, which are present in different concentrations in everything and, of course, in our food.

Every element affects our health. The content of elements in food products is very variable. A more stable and constant value is the content of elements in the body of a healthy person, although it may also have variability (variability).

For the human body, the role of about 30 chemical elements has been definitely established, without which it cannot exist normally. These elements are called vital. In addition to them, there are elements that in small quantities do not affect the functioning of the body, but at certain levels are poisons.

Macronutrients- content in the body of more than one gram: phosphorus, potassium, sulfur, sodium, chlorine, magnesium, iron, fluorine, zinc, silicon, zirconium - 11 elements.

Microelements- content in the body of more than one milligram: rubidium, strontium, bromine, lead, niobium, copper, aluminum, cadmium, barium, boron (top ten microelements), tellurium, vanadium, arsenic, tin, selenium, titanium, mercury, manganese, iodine , nickel, gold, molybdenum, antimony, chromium, yttrium, cobalt, cesium, germanium - 28 elements. Every element affects our health. The content of elements in food products is very variable. A more stable and constant value is the content of elements in the body of a healthy person, although it may also have variability (variability).

The assumptions of some scientists go further. They believe that not only are all chemical elements present in a living organism, but each of them performs a specific biological function. It is quite possible that this hypothesis will not be confirmed. However, as research in this direction develops, the biological role of an increasing number of chemical elements is revealed.

The human body consists of 60% water, 34% organic matter and 6% inorganic matter. The main components of organic substances are carbon, hydrogen, oxygen, they also include nitrogen, phosphorus and sulfur. Inorganic substances of the human body necessarily contain 22 chemical elements: Ca, P, O, Na, Mg, S, B, Cl, K, V, Mn, Fe, Co, Ni, Cu, Zn, Mo, Cr, Si, I ,F,Se.

For example, if a person weighs 70 kg, then it contains (in grams): calcium - 1700, potassium - 250, sodium - 70, magnesium - 42, iron - 5, zinc - 3.

Scientists have agreed that if the mass fraction of an element in the body exceeds 10-2%, then it should be considered a macroelement. The proportion of microelements in the body is 10-3-10-5%.

There are a large number of chemical elements, especially heavy ones, which are poisons for living organisms - they have adverse biological effects. These elements include: Ba, Ni, Pd, Pt, Au, Ag, Hg, Cd, Tl, Pb, As, Sb, Se.

There are elements that are poisonous in relatively large quantities, but have a beneficial effect in low concentrations. For example, arsenic, a strong poison that disrupts the cardiovascular system and affects the kidneys and liver, is beneficial in small doses, and doctors prescribe it to improve appetite. Oxygen, which a person needs for breathing, in high concentrations (especially under pressure) has a toxic effect. Among the impurity elements there are also those that in small doses have effective healing properties. Thus, the bactericidal (causing the death of various bacteria) property of silver and its salts was noticed long ago. For example, in medicine, a solution of colloidal silver (collargol) is used to wash purulent wounds, the bladder, for chronic cystitis and urethritis, as well as in the form of eye drops for purulent conjunctivitis and blennorrhea. Silver nitrate pencils are used to cauterize warts and granulations. In diluted solutions (0.1-0.25%), silver nitrate is used as an astringent and antimicrobial agent for lotions, and also as eye drops. Scientists believe that the cauterizing effect of silver nitrate is associated with its interaction with tissue proteins, which leads to the formation of protein salts of silver - albuminates. Silver is not yet classified as a vital element, but its increased content in the human brain, endocrine glands, and liver has already been experimentally established. Silver enters the body through plant foods, such as cucumbers and cabbage.

A very interesting question is about the principles of nature’s selection of chemical elements for the functioning of living organisms. There is no doubt that their prevalence is not a decisive factor. A healthy body itself is able to regulate the content of individual elements. Given a choice (food and water), animals can instinctively contribute to this regulation. The capabilities of plants in this process are limited.

Organic substances of the cell. The main vital compounds are proteins, fats and carbohydrates. Biopolymers.

Organic compounds make up on average 20-30% of the cell mass of a living organism. These include biological polymers, proteins, carbohydrates, lipids, hormones, nucleic acids, and vitamins.

Biological polymers– organic compounds that make up the cells of living organisms. A polymer is a multi-link chain of simple substances - monomers (n ÷ 10 thousand - 100 thousand monomers.

The properties of biopolymers depend on the structure of their molecules, on the number and variety of monomer units. If the monomers are different, then their repeated alternations in the chain create a regular polymer.

…A – A – B – A – A – B... regular

…A – A – B – B – A – B – A... irregular

Carbohydrates

General formula Сn(H 2 O)m

Carbohydrates play the role of energy substances in the human body. The most important of them are sucrose, glucose, fructose, and starch. They are quickly absorbed ("burned") in the body. The exception is fiber (cellulose), which is especially abundant in plant foods. It is practically not absorbed by the body, but is of great importance: it acts as ballast and helps digestion, mechanically cleansing the mucous membranes of the stomach and intestines. There are a lot of carbohydrates in potatoes and vegetables, cereals, pasta, fruits and bread.

Example: glucose, ribose, fructose, deoxyribose – monosaccharides. Sucrose – disaccharides. Starch, glycogen, cellulose - polysaccharides

Being in nature: in plants, fruits, pollen, vegetables (garlic, beets), potatoes, rice, corn, wheat grain, wood...

Their functions:

1) energy: during oxidation to CO2 and H2O, energy is released; excess energy is stored in liver and muscle cells in the form of glycogen;

2) construction: in a plant cell - a strong base of cell walls (cellulose);

3) structural: they are part of the intercellular substance of the skin and cartilage tendons;

4) recognition by other cells: as part of cell membranes, if separated liver cells are mixed with kidney cells, they will independently separate into two groups due to the interaction of cells of the same type.

Lipids (lipoids, fats)

Lipids include various fats, fat-like substances, phospholipids... All of them are insoluble in water, but soluble in chloroform, ether...

Being in nature: in animal and human cells in the cell membrane; between the cells is the subcutaneous layer of fat.

Functions:

1) thermal insulation (in whales, pinnipeds...);

2) reserve nutrient;

3) energy: energy is released during the hydrolysis of fats;

4) structural: some lipids serve as an integral part of cell membranes.

Fats also serve as a source of energy for the human body. The body stores them “in reserve” and they serve as a long-term energy source. In addition, fats have low thermal conductivity and protect the body from hypothermia. It is not surprising that the traditional diet of northern peoples contains so much animal fat. For people engaged in heavy physical labor, it is also easiest (although not always healthier) to compensate for the energy expended with fatty foods. Fats are part of cell walls, intracellular formations, and nervous tissue. Another function of fats is to supply fat-soluble vitamins and other biologically active substances to the body tissues.

Squirrels

Drawing - Protein molecule

Squirrels– biopolymers whose monomers are amino acids.

The formation of linear protein molecules occurs as a result of reactions of amino acids with each other.

Sources of proteins can be not only animal products (meat, fish, eggs, cottage cheese), but also plant products, for example, legumes (beans, peas, soybeans, peanuts, which contain up to 22–23% proteins by weight), nuts and mushrooms . However, the most protein is in cheese (up to 25%), meat products (pork 8–15%, lamb 16–17%, beef 16–20%), poultry (21%), fish (13–21%), eggs (13%), cottage cheese (14%). Milk contains 3% proteins, and bread 7–8%. Among cereals, the champion in proteins is buckwheat (13% of proteins in dry cereals), which is why it is recommended for dietary nutrition. To avoid “excesses” and at the same time ensure the normal functioning of the body, it is necessary, first of all, to give a person a complete set of proteins with food. If there is not enough protein in the diet, an adult feels a loss of strength, his performance decreases, and his body is less resistant to infections and colds. As for children, if they have inadequate protein nutrition, they are greatly behind in development: children grow, and proteins are the main “building material” of nature. Every cell of a living organism contains proteins. Human muscles, skin, hair, and nails consist mainly of proteins. Moreover, proteins are the basis of life; they participate in metabolism and ensure the reproduction of living organisms.

Structure:

primary structure– linear, with alternating amino acids;

secondary– in the form of a spiral with weak bonds between the turns (hydrogen);

tertiary– a spiral rolled into a ball;

quaternary– when combining several chains that differ in their primary structure.

Functions:

1) construction: proteins are an essential component of all cellular structures;

2) structural: proteins in combination with DNA make up the body of chromosomes, and with RNA – the body of ribosomes;

3) enzymatic: chemical catalyst. reactions are performed by any enzyme - a protein, but a very specific one;

4) transport: transfer of O 2 and hormones in the body of animals and humans;

5) regulatory: proteins can perform a regulatory function if they are hormones. For example, insulin (a hormone that supports the functioning of the pancreas) activates the uptake of glucose molecules by cells and their breakdown or storage inside the cell. With a lack of insulin, glucose accumulates in the blood, developing diabetes;

6) protective: when foreign bodies enter the body, protective proteins are produced - antibodies, which bind to foreign bodies, combine and suppress their vital activity. This mechanism of resistance of the body is called immunity;

7) energy: with a lack of carbohydrates and fats, amino acid molecules can be oxidized.

The concept of "life". The main signs of living things: nutrition, respiration, excretion, irritability, mobility, reproduction, growth and development.

Biology– the science of the origin and development of living things, their structure, forms of organization and methods of activity. Currently, there are more than 50 sciences within the complex of biological knowledge, among them: botany, zoology, anatomy, morphology, biophysics, biochemistry, ecology, etc. This diversity of scientific disciplines is explained by the complexity of the object of study - living matter.

From this point of view, it is especially important to understand what criteria underlie the division of matter into living and nonliving.

In classical biology, two opposing positions competed, explaining the essence of living things in fundamentally different ways - reductionism and vitalism.

Supporters reductionism believed that all life processes of organisms can be reduced to a set of certain chemical reactions. Term "reductionism" comes from the Latin word redaction - to move back, to return. Ideas of biological reductionism relied on the ideas of vulgar mechanistic materialism, which became most widespread in the philosophy of the 17th and 18th centuries. Mechanistic materialism explained all processes occurring in nature from the point of view of the laws of classical mechanics. Adaptation of the mechanistic materialist position to biological cognition led to the formation of biological reductionism. From the point of view of modern natural science, a reductionistic explanation cannot be considered satisfactory, since it emasculates the very essence of living things. Most widely distributed reductionism received in the 18th century.

The opposite of reductionism is vitalism, whose supporters explain the specificity of living organisms by the presence of a special vital force in them. Term "vitalism" comes from the Latin word vita - life. The philosophical basis of vitalism is idealism. Vitalism did not explain the specifics and mechanisms of the functioning of living things, reducing all the differences between the organic and the inorganic to the action of a mysterious and unknown “vital force”.

Modern biology considers the main properties of living things to be:

1) independent metabolism,

2) irritability,

4) ability to reproduce,

5) mobility,

6) adaptability to the environment

Based on the totality of these properties, living things differ from non-living things. Biological systems- These are holistic open systems that constantly exchange matter, energy, information with the environment and are capable of self-organization. Living systems actively respond to environmental changes and adapt to new conditions. Certain qualities of living things may also be inherent in inorganic systems, but none of the inorganic systems possesses the totality of the listed properties.

There are transitional forms that combine the properties of living and nonliving, for example viruses. Word "virus" derived from the Latin virus - poison. Viruses were discovered in 1892 by the Russian scientist D. Ivanovsky. On the one hand, they consist of proteins and nucleic acids and are capable of self-reproduction, i.e. have signs of living organisms, but on the other hand, outside a foreign organism or cell they do not show signs of living things - they do not have their own metabolism, do not react to stimuli, and are not capable of growth and reproduction.

All living beings on Earth have the same biochemical composition: 20 amino acids, 5 nitrogenous bases, glucose, fats. Modern organic chemistry knows more than 100 amino acids. Apparently, such a small number of compounds that form all living things is the result of selection that occurred at the stage of prebiological evolution. Proteins that make up living systems are high-molecular organic compounds. In any given protein, the order of amino acids is always the same. Most proteins act as enzymes - catalysts for chemical reactions occurring in living systems.

A significant achievement of classical biology was the creation of the theory of the cellular structure of living organisms. In the complex of modern biological knowledge, there is a separate discipline that deals with the study of cells - cytology.

The concept of “cell” was introduced into scientific use by the English botanist R. Hooke in 1665. Examining the media of dried cork, he discovered many cells, or chambers, which he called cells. However, two centuries passed from the moment of this discovery to the creation of the cell theory.

In 1837, the German botanist M. Schleiden proposed a theory of the formation of plant cells. According to Schleiden, the cell nucleus plays an important role in the reproduction and development of cells, the existence of which was established in 1831 by R. Brown.

In 1839, M. Schleiden’s compatriot, anatomist T. Schwann, based on experimental data and theoretical conclusions, created a cellular theory of the structure of living organisms. The creation of cell theory in the mid-19th century was a significant step in the establishment of biology as an independent scientific discipline.

Basic principles of cell theory

1. A cell is an elementary biological unit, the structural and functional basis of all living things.

2. The cell carries out independent metabolism, is capable of division and self-regulation.

3. The formation of new cells from non-cellular material is impossible; cell reproduction occurs only through cell division.

The cellular theory of the structure of living organisms has become a convincing argument in favor of the idea of ​​the unity of the origin of life on Earth and has had a significant influence on the formation of the modern scientific picture of the world.

Substances such as sand, clay, various minerals, water, carbon oxides, carbonic acid, its salts and others found in “inanimate nature” are called inorganic or mineral substances.

Of the approximately one hundred chemical elements found in the earth's crust, only sixteen are necessary for life, and four of them - hydrogen (H), carbon (C), oxygen (O) and nitrogen (N) are the most common in living organisms and account for 99% masses of living things. The biological significance of these elements is associated with their valency (1, 2, 3, 4) and the ability to form strong covalent bonds, which are stronger than the bonds formed by other elements of the same valency. The next most important are phosphorus (P), sulfur (S), sodium, magnesium, chlorine, potassium and calcium ions (Na, Mg, Cl, K, Ca). Iron (Fe), cobalt (Co), copper (Cu), zinc (Zn), boron (B), aluminum (Al), silicon (Si), vanadium (V), molybdenum ( Mo), iodine (I), manganese (Mn).

All chemical elements in the form of ions or as part of certain compounds participate in the construction of the body. For example, carbon, hydrogen and oxygen are found in carbohydrates and fats. In the composition of proteins, nitrogen and sulfur are added to them, in the composition of nucleic acids - nitrogen, phosphorus, iron, which are involved in the construction of the hemoglobin molecule; magnesium is found in chlorophyll; copper is found in some oxidative enzymes; iodine is contained in the thyroxine molecule (thyroid hormone); sodium and potassium provide electrical charge on the membranes of nerve cells and nerve fibers; zinc is included in the molecule of the pancreatic hormone - insulin; Cobalt is found in vitamin B12.

Compounds of nitrogen, phosphorus, calcium and other inorganic substances serve as a source of building material for the synthesis of organic molecules (amino acids, proteins, nucleic acids, etc.) and are part of a number of supporting structures of the cell and organism. Some inorganic ions (for example, calcium and magnesium ions) are activators and components of many enzymes, hormones and vitamins. With a lack of these ions, vital processes in the cell are disrupted.

Inorganic acids and their salts perform important functions in living organisms. Hydrochloric acid is part of the gastric juice of animals and humans, accelerating the process of digesting food proteins. Residues of sulfuric acid, joining foreign substances insoluble in water, give them solubility, facilitating their removal from the body. Inorganic sodium and potassium salts of nitrous and phosphoric acids serve as important components of the mineral nutrition of plants; they are added to the soil as fertilizers. Calcium and phosphorus salts are part of animal bone tissue. Carbon dioxide (CO2) is constantly formed in nature during the oxidation of organic substances (rotting plant and animal remains, respiration, combustion of fuel) in large quantities, it is released from volcanic cracks and from the waters of mineral springs.

Water is a very common substance on Earth. Almost the surface of the globe is covered with water, forming oceans and seas. Rivers, lakes. Much water exists as a gaseous vapor in the atmosphere; it lies in the form of huge masses of snow and ice all year round on the tops of high mountains and in the polar countries in the bowels of the Earth there is also water that saturates the soil and rocks.

Water is very important in the life of plants, animals and humans. According to modern ideas, the very origin of life is connected with the sea. In any organism, water is the medium in which chemical processes take place that ensure the life of the organism; in addition, it itself takes part in a number of biochemical reactions.

The chemical and physical properties of water are quite unusual and are associated mainly with the small size of its molecules, with the polarity of its molecules and with their ability to connect with each other through hydrogen bonds.

Let's consider the biological significance of water. Water - excellent solvent for polar substances. These include ionic compounds, such as salts, in which charged particles (ions) dissociate (separate from each other) in water when the substance is dissolved, as well as some non-ionic compounds, such as sugars and simple alcohols, which contain charged molecules. (polar) groups (in sugars and alcohols these are OH groups). When a substance goes into solution, its molecules or ions are able to move more freely and, accordingly, its reactivity increases. For this reason, most chemical reactions in a cell occur in aqueous solutions. Non-polar substances, such as lipids, do not mix with water and therefore can separate aqueous solutions into separate compartments, just as membranes separate them. The non-polar parts of the molecules are repelled by water and, in its presence, are attracted to each other, as happens, for example, when oil droplets merge into larger droplets; in other words, nonpolar molecules are hydrophobic. Such hydrophobic interactions play an important role in ensuring the stability of membranes, as well as many protein molecules and nucleic acids. The inherent properties of water as a solvent also mean that water serves as a medium for the transport of various substances. It performs this role in the blood, in the lymphatic and excretory systems, in the digestive tract and in the phloem and xylem of plants.

Water has great heat capacity. This means that a significant increase in thermal energy causes only a relatively small increase in its temperature. This phenomenon is explained by the fact that a significant part of this energy is spent on breaking hydrogen bonds that limit the mobility of water molecules, i.e., on overcoming its stickiness. The high heat capacity of water minimizes the temperature changes occurring in it. Thanks to this, biochemical processes occur in a smaller temperature range, at a more constant speed, and the danger of disruption of these processes from sudden temperature deviations threatens them less strongly. Water serves as a habitat for many cells and organisms, which is characterized by a fairly significant constancy of conditions.

Water is characterized by large heat of vaporization. The latent heat of evaporation (or relative latent heat of evaporation) is a measure of the amount of thermal energy that must be imparted to a liquid in order for it to transform into vapor, that is, to overcome the forces of molecular cohesion in the liquid. Evaporation of water requires quite significant amounts of energy. This is explained by the existence of hydrogen bonds between water molecules. It is because of this that the boiling point of water, a substance with such small molecules, is unusually high.

The energy required for water molecules to evaporate comes from their environment. Thus, evaporation is accompanied by cooling. This phenomenon is used in animals during sweating, during thermal dyspnea in mammals or in some reptiles (for example, crocodiles), which sit in the sun with their mouths open; it may also play a significant role in cooling transpiring leaves. The latent heat of fusion (or relative latent heat of fusion) is a measure of the thermal energy required to melt a solid (ice). Water needs a relatively large amount of energy to melt (melt). The opposite is also true: when water freezes, it must release a large amount of thermal energy. This reduces the likelihood of the cell contents and surrounding fluid freezing. Ice crystals are especially harmful to living things when they form inside cells.

Water is the only substance that has more density, than in solid. Since ice floats in water, it forms when it freezes first on its surface and only finally in the bottom layers. If the freezing of ponds occurred in the reverse order, from bottom to top, then in areas with a temperate or cold climate, life in freshwater bodies could not exist at all. Ice covers the water column like a blanket, which increases the chances of survival for the organisms living in it. This is important in cold climates and during the cold season, but undoubtedly it played a particularly important role during the Ice Age. Being on the surface, ice melts faster. The fact that layers of water whose temperature has fallen below 4 degrees rise upward causes their movement in large bodies of water. The nutrients contained in it circulate along with the water, due to which water bodies are populated by living organisms to great depths.

The water has a big surface tension and cohesion. Cohesion- this is the adhesion of molecules of a physical body to each other under the influence of attractive forces. There is surface tension on the surface of a liquid - the result of cohesive forces acting between molecules, directed inward. Due to surface tension, the liquid tends to take a shape such that its surface area is minimal (ideally, a spherical shape). Of all liquids, water has the highest surface tension. The significant cohesion characteristic of water molecules plays an important role in living cells, as well as in the movement of water through xylem vessels in plants. Many small organisms benefit from surface tension: it allows them to float on water or glide across its surface.

The biological significance of water is also determined by the fact that it is one of the necessary metabolites, i.e., it participates in metabolic reactions. Water is used, for example, as a source of hydrogen in the process of photosynthesis, and also participates in hydrolysis reactions.

The role of water for living organisms is reflected, in particular, in the fact that one of the main factors of natural selection influencing speciation is the lack of water (limiting the distribution of some plants with motile gametes). All terrestrial organisms are adapted to obtain and conserve water; in their extreme manifestations - in xerophytes, in desert-dwelling animals, etc. This kind of adaptation seems to be a true miracle of nature’s ingenuity.

Biological functions of water:

In all organisms:

1) ensures the maintenance of structure (high water content in protoplasm); 2) serves as a solvent and medium for diffusion; 3) participates in hydrolysis reactions; 4) serves as a medium in which fertilization occurs;

5) ensures the dispersal of seeds, gametes and larval stages of aquatic organisms, as well as the seeds of some terrestrial plants, such as the coconut palm.

In plants:

1) determines osmosis and turgidity (on which many things depend: growth (enlargement of cells), maintenance of structure, movement of stomata, etc.); 2) participates in photosynthesis; 3) provides transport of inorganic ions and organic molecules; 4) ensures seed germination - swelling, rupture of the seed coat and further development.

In animals:

1) provides transport of substances;

2) determines osmoregulation;

3) promotes body cooling (sweating, thermal shortness of breath);

4) serves as one of the components of lubrication, for example in joints;

5) has supporting functions (hydrostatic skeleton);

6) performs a protective function, for example in tear fluid and mucus;

7) promotes migration (sea currents).



Excretory functions are carried out by the gastrointestinal tract; external respiratory organs; sweat, sebaceous, lacrimal, mammary and other glands, as well as kidneys (Fig. 1.14), with the help of which decay products are removed from the body.

Rice. 1.14.

An important organ of the excretory system is the kidneys, which are directly involved in the regulation of water and mineral metabolism, ensure acid-base balance (balance) in the body, and form biologically active substances, such as renin, which affects blood pressure levels.

Chemical structure of the human body

The human body contains organic and inorganic substances. Water makes up 60% of body weight, and minerals average 4%. Organic substances are represented mainly by proteins (18%), fats (15%), carbohydrates (2-3%). All substances of the body, as well as inanimate nature, are built from atoms of various chemical elements.

Of the 110 known chemical elements, the human body contains mainly 24 (Table 1.2). Depending on their quantity in the body, chemical elements are divided into basic, macro-, micro- and ultramicroelements.

Note that individual chemical elements accumulate unevenly in various organs and tissues of the human body. For example, bone tissue accumulates calcium and phosphorus, blood - iron, thyroid gland - iodine, liver - copper, skin - strontium, etc.

The quantitative and qualitative composition of the chemical elements of the body depends both on external environmental factors (nutrition, ecology, etc.) and on the functions of individual organs.

Macronutrients and their importance in the body is determined by the fact that they are necessary for the implementation of many biological

Table 1.2

Chemical elements that make up the human body

(according to N.I. Volkov)

	Chemical element
Basic	Oxygen (O)		Total 99.9%
elements	Carbon (C)
	Hydrogen (H) Nitrogen (N)
Macronutrients	Calcium (Ca)
	Phosphorus (P)
	Sodium (Na)
	Magnesium (Mg)
Micro and ultra
microelements	Fluorine (F) Silicon (Si) Vanadium (V) Chromium (Cr) Manganese (Mn) Iron (Fe) Cobalt (Co) Copper (Cu) Zinc (Zn) Selenium (Se)
	Molybdenum (Mo) Iodine (J)

chemical processes. They are essential nutritional factors, as they are not produced in the body. The mineral content is relatively low (4-10% of dry body weight) and depends on the functional state of the body, its age, nutritional status and environmental conditions.

Calcium in the human body makes up 40% of the total amount of all minerals. It is part of teeth and bones, giving them strength. A decrease in the flow of calcium into the body’s tissues leads to its release from the bones, which causes a decrease in their strength (osteoporosis), as well as dysfunction of the nervous system, blood circulation, including muscle activity.

Phosphorus makes up 22% of the amount of all minerals. About 80% of its amount is found in tissues in the form of calcium phosphate. Phosphorus plays an important role in the processes of energy formation, since in the form of phosphoric acid residues it is included in the composition of energy sources - ATP, ADP, CrP, various nucleotides, as well as in the composition of hydrogen carriers and some metabolic products.

Sodium and potassium found in all tissues and fluids of the body. Potassium is predominantly inside cells, sodium - in the extracellular space. Both are involved in the conduction of nerve impulses, tissue stimulation, creation of osmotic blood pressure (osmotic active ions), maintaining acid-base balance, and also affect the activity of the enzymes Naf, Kf, ATPase. These elements regulate water exchange in the body: sodium ions retain water in tissues and cause swelling of proteins (formation of colloids), which leads to edema; Potassium ions, on the contrary, enhance the excretion of sodium and water from the body. Insufficiency of sodium and potassium in the body causes disruption of the central nervous system, muscle contractile apparatus, cardiovascular and digestive systems, which leads to a decrease in physical performance.

Magnesium in the tissues of the body is in a certain ratio with calcium. It affects energy metabolism, protein synthesis, since it is an activator of many enzymes, which are called kinases and perform the function of transferring a phosphate group from an ATP molecule to various substrates. Magnesium also affects muscle excitability and helps remove cholesterol from the body.

Its deficiency leads to increased neuromuscular excitability, the appearance of cramps and muscle weakness.

Chlorine refers to osmotic active substances and is involved in the regulation of osmotic pressure and water metabolism of body cells, used for the formation of hydrochloric acid (HC1) - an essential component of gastric juice. Lack of chlorine in the body can lead to a decrease in blood pressure, contributes to myocardial infarction, and causes fatigue, irritability, and drowsiness.

Micro- and ultra-microelements. Iron plays a very important role in the processes of aerobic energy formation in the body. It is part of the proteins hemoglobin and myoglobin, which transport 0 2 and CO 2 in the body, as well as cytochromes - components of the respiratory chain in which the processes of biological oxidation and formation of LTP occur. Iron deficiency in the body leads to impaired formation of hemoglobin and a decrease in its concentration in the blood. This can lead to the development of iron deficiency anemia, a decrease in the oxygen capacity of the blood and a sharp decrease in physical performance.

Zinc is part of many energy metabolism enzymes, as well as carbonic anhydrase enzymes, which catalyze the exchange of H 2 CO 3 and lactate dehydrogenase, which regulate the oxidative breakdown of lactic acid. It participates in the creation of the active structure of the insulin protein - the pancreatic hormone, and enhances the effect of pituitary (gonadotropic) and gonadal hormones (testosterone, estrogen) on the processes of protein synthesis. Zinc deficiency can lead to weakened immunity, loss of appetite, and slower growth processes.

Copper promotes body growth, enhances hematopoietic processes, affects the rate of glucose oxidation and glycogen breakdown. It is part of the enzymes of the respiratory chain, increases the activity of lipase, pepsin and other enzymes.

Manganese, cobalt, chromium are used by the body as activators of many enzymes that take part in the metabolism of carbohydrates, proteins, lipids, cholesterol synthesis, affect hematopoietic processes, and increase the body's defenses. Chromium also enhances protein synthesis, exhibiting an anabolic effect. Manganese is involved in the synthesis of vitamin C, which is very important for athletes.

Iodine necessary for the construction of thyroid hormones - thyroxine and its derivatives. Its deficiency in the body leads to diseases of the thyroid gland (endemic goiter): 150 mcg satisfies the body's daily need for iodine.

Fluorine is part of tooth enamel and dentin. Its excess suppresses the processes of tissue respiration and fatty acid oxidation. Insufficient fluoride causes dental disease (caries), and excess causes enamel staining (fluorosis).

Selenium has an antioxidant effect, i.e. protects cells from excessive lipid peroxidation, which leads to the accumulation of harmful hydrogen peroxides in tissues. The latest research suggests that selenium strengthens the immune system and prevents the occurrence of cancer cells, and is involved in the transfer of genetic information.

Inorganic substances are chemical compounds that, unlike organic ones, do not contain carbon (except for cyanides, carbides, carbonates and some other compounds traditionally belonging to this group).

The classification of inorganic substances is as follows. There are simple substances: nonmetals (H2, N2, O2), metals (Na, Zn, Fe), amphoteric simple substances (Mn, Zn, Al), noble gases (Xe, He, Rn) and complex substances: oxides (H2O, CO2, P2O5); hydroxides (Ca(OH)2, H2SO4); salts (CuSO4, NaCl, KNO3, Ca3(PO4)2) and binary compounds.

Molecules of simple (single-element) substances consist only of atoms of a certain (one) type (element). They do not decompose in chemical reactions and are not capable of forming other substances. Simple substances, in turn, are divided into metals and non-metals. There is no clear boundary between them due to the ability of simple substances to exhibit dual properties. Some elements simultaneously exhibit properties of both metals and non-metals. They are called amphoteric.

Noble gases are a separate class of inorganic substances; they stand out among others by their special originality. VIIIA-groups.

The ability of some elements to form several simple ones, differing in structure and properties, is called allotropy. Examples include the elements C, diamond-forming carbine and graphite; O - ozone and oxygen; R - white, red, black and others. This phenomenon is possible due to the different number of atoms in the molecule and due to the ability of atoms to form different crystalline forms.

In addition to simple ones, the main classes of inorganic substances include complex compounds. Complex (two- or multi-element) substances mean compounds of chemical elements. Their molecules are made up of different types of atoms (different elements). When decomposed in chemical reactions, they form several other substances. They are divided into bases and salts.

In bases, metal atoms are connected to hydroxyl groups (or one group). These compounds are divided into soluble (alkali) and insoluble in water.

Oxides consist of two elements, one of which is necessarily oxygen. They are non-salt-forming and salt-forming.

Hydroxides are substances that are formed by interaction (direct or indirect) with water. These include: bases (Al(OH)3, Ca(OH)2), acids (HCl, H2SO4, HNO3, H3PO4), (Al(OH)3, Zn(OH)2). When different types of hydroxides interact with each other, oxygen-containing salts are formed.

Salts are divided into medium salts (consist of cations and anions - Ca3(PO4)2, Na2SO4); acidic (contain hydrogen atoms in the acidic residue, which can be replaced by cations -NaHSO3, CaHPO4), basic (contain a hydroxo or oxo group - Cu2CO3(OH)2); double (contain two different chemical cations) and/or complex (contain two different acidic residues) salts (CaMg(CO3)2, K3).

Binary compounds (a fairly large class of substances) are divided into oxygen-free acids (H2S, HCl); oxygen-free salts (CaF2, NaCl) and other compounds (CaC2, AlH3, CS2).

Inorganic substances do not have a carbon skeleton, which is the basis of organic compounds.

The human body contains both (34%) and inorganic compounds. The latter include, first of all, water (60%) and calcium salts, of which the human skeleton mainly consists.

Inorganic substances in the human body are represented by 22 chemical elements. Most of them are metals. Depending on the concentration of elements in the body, they are called micro-elements (the content of which in the body is not more than 0.005% of body weight) and macroelements. Microelements essential for the body are iodine, iron, copper, zinc, manganese, molybdenum, cobalt, chromium, selenium, and fluorine. Their intake from food into the body is necessary for its normal functioning. Macroelements such as calcium, phosphorus and chlorine are the basis of many tissues.