Any living organism functions fully only if it is sufficiently supplied with micro- and macroelements. They come only from the outside, are not synthesized independently, but help the absorption of other elements. In addition, such chemical elements ensure the uninterrupted functioning of the entire body and its restoration in case of “problems”. What are macro- and microelements, why do we need them, as well as a list of products containing one or another option, is offered in our article.

Our body's need for these chemicals, called "microelements", is minimal. That is why this name came about, but the benefits of this group are not in last place. Microelements are chemical compounds that are found in the body in negligible proportions (less than 0.001% of body weight). Their reserves must be replenished regularly, because they are required for daily work and normal functioning of the body.

Which foods contain essential microelements:

Name	Daily norm	Effect on the body	What products contain
Iron	From 10 to 30 mg.	Participates in the processes of hematopoiesis and supply of oxygen to all organs and tissues.	Pork, turkey, liver, legumes, nuts, vegetable oils, porcini mushrooms, buckwheat, eggs, cabbage, sea fish, cottage cheese, rose hips, apples, beets, carrots, garden and forest berries, greens.
Copper	Children up to 2 mg/day, adults about 3 mg, pregnant and lactating women an average of 4 - 5 mg.	Promotes the formation of hemoglobin and plays an important role in maintaining optimal blood composition.	Liver, legumes and grains, dried fruits, citrus fruits, eggs, dairy and fermented milk products, berries.
Iodine	The daily norm is 2 – 4 mcg/kg of human weight.	Promotes normal synthesis of thyroid hormones. Strengthens the immune system, regulates the functioning of the central nervous system and cardiovascular systems.	Sea and ocean fish, seafood, cod liver, carrots, cabbage, asparagus, beans, greens and leafy vegetables, grapes, strawberries, pineapple.
Zinc	From 10 to 25 mg, exceeding the norm up to 150 mg leads to toxic effects on the body.	Stimulation of brain activity, sexual activity, regeneration processes.	Sea fish and seafood, legumes, cottage cheese, eggs, carrots, beets, mushrooms, milk, figs, honey, apples, lemons, black currants and raspberries.
Chromium	Consumption ranges from 100 to 200 mcg/day. Excess leads to pulmonary diseases.	Strengthens bone tissue, promotes intoxication of the body and reduces cholesterol levels in the blood.	Meat and offal, legumes and grain bread, dairy products, potatoes, milk, onions, corn, cherries, plums, Jerusalem artichokes, blueberries and hazelnuts.
Cobalt	About 40 - 70 mcg.	Normalization of the pancreas.	Fermented milk products, eggs, fish, corn, liver and meat by-products, nuts, butter, legumes, strawberries, wild strawberries, cocoa and chocolate.
Selenium	The optimal dosage is from 5 mcg to 1 mg. An excess of more than 5 mg/day leads to poisoning of the body.	Neutralization of toxins and free radicals. Prevention of viral diseases.	Olive oil, brewer's yeast, legumes and grains, nuts, fish, organ meats, olives, garlic, mushrooms, sour cream.
Manganese	From 5 to 10 mg.	Stimulation of the immune system, formation of bone tissue, removal of toxins.	Leafy vegetables and greens, sea fish, legumes and grains, fruits, garden and forest berries, brewer's yeast, dairy products, nuts, eggs, seeds and chocolate.
Molybdenum	Children under 10 years old - no more than 20 - 150 mcg / day, adults - 75 - 300 mcg / day.	Ensuring cellular respiration, regulating metabolic processes and removing uric acid from the body.	Legumes and cereals, rice, corn, cabbage, garlic, rose hips, carrots, sunflower seeds, pistachios.
Bor	From 0.2 to 3 mcg.	Strengthening the skeleton and bone tissue, normalizing hormonal metabolism, the functioning of the endocrine system and lipid-fat metabolism.	Legumes, all types of cabbage, seafood, nuts, meat, fish, milk, prunes, apples and pears, dried fruits, grapes, raisins and honey.
Fluorine	From 0.5 to 4 mg/day.	Participates in the formation of bone and dental tissue.	Mineral water, cod liver, sea fish, meat, milk, seafood, nuts, leafy vegetables and herbs, eggs, pumpkin, fruits and berries.
Bromine	From 0.5 to 2 mg/day.	Regulation of the nervous system, increasing the activity of sexual function.	Dairy and bakery products, nuts, fish, legumes, dried fruits.
Lithium	The norm is up to 90 mcg/day, excess and intoxication occurs when up to 150 - 200 mcg/day is exceeded.	Prevention of nervous excitement, neutralization of the effects of alcohol in the body.	Meat and offal, fish, potatoes, tomatoes, herbs.
Silicon	From 20 to 50 mcg.	Provides tissue elasticity, strengthens bones and teeth, improves the functioning of the cardiovascular system.	Cereals, potatoes, Jerusalem artichoke, carrots, beets, bell peppers, caviar, fish, mushrooms, milk and dairy products, mineral water, nuts, grapes, wild berries, grapes, apricots, bananas, dried fruits.
Nickel	From 100 to 300 mcg/day.	Hormonal regulation, lowering blood pressure.	Sea fish, meat by-products, dairy and bakery products, carrots, leafy greens, mushrooms, berries and fruits.
Vanadium	From 10 to 25 mcg.	Regulation of carbohydrate metabolism, lowering cholesterol, providing the body with energy, normalizing the functioning of the pancreas.	Seafood, fish, nuts, legumes and grains, greens, cherries, strawberries, mushrooms, fatty meats, liver and meat by-products.

In total, there are about thirty microelements that are most important for our body. They are classified into vital for our body (they are often called essential) and conditionally essential, the lack of which does not lead to serious disorders. Unfortunately, most of us experience ongoing or recurring micronutrient imbalances, which can lead to poor health and well-being.

Macronutrients

Chemicals that the body needs higher than microelements are called “macroelements.” What are macronutrients? Usually they are not presented in pure form, but as part of organic compounds. They enter the body with food and water. The daily requirement is also higher than for microelements, so a lack of one or another macroelement leads to a noticeable imbalance and deterioration in a person’s well-being.

Value and sources of macronutrient replenishment:

Name	Daily norm	Effect on the body	What products contain
Magnesium	About 400 mg/day.	Responsible for the health of muscles, nerves and immune system.	Cereals and legumes, nuts, milk, cottage cheese, fresh vegetables.
Calcium	Adults up to 800 mg/day.	Participates in the processes of bone tissue formation, normalizes the activity of the cardiovascular system.	Dairy and fermented milk products, meat, fish and seafood.
Phosphorus	Daily dose up to 1200 mg.	Necessary for brain activity, construction of bone and muscle tissue.	Sea and ocean fish, meat and bakery products, legumes, cereals, hard cheese.
Sodium	No more than 800 mg/day. An excess is fraught with swelling and increased blood pressure.	Necessary for regulating water balance in the body, affects blood pressure levels, the formation of bone and muscle tissue.	Table and sea salt. Many pure foods contain minimal amounts of sodium.
Potassium	2500 – 5000 mg/day.	Provides balanced the functioning of internal systems, normalizes blood pressure and ensures the transmission of nerve impulses.	Potatoes, legumes and cereals, apples and grapes.
Chlorine	Approximately 2 g/day.	Participates in the formation of gastric juice and blood plasma.	Table salt and bakery products.
Sulfur	Up to 1 g/day.	It is part of proteins, normalizes their structure and internal exchange between body tissues.	Products of animal origin: eggs, meat and meat products, fish, dairy and fermented milk products.

If the body receives insufficient micro- and macroelements, the deficiency is compensated for with special multivitamin complexes. It is best to choose the appropriate drug together with your doctor, based on special tests. They will show you exactly what your body needs. It is also very important to prevent an overabundance of elements, because this can lead to much more complex consequences. For example, when the consumption rate of bromine, selenium or phosphorus increases, the body is poisoned and its normal functioning is disrupted.

The existence of essential macro- and microelements was discovered relatively recently, but the benefits for our body are difficult to overestimate. Macro and microelements are involved in important functioning processes and ensure the digestibility of food. The lack of one or another element negatively affects the overall functioning of the body's systems, so you should definitely pay attention to the maximum variety of diet and the supply of these elements from the outside.

Microelements are the active substance of microfertilizers.

Show all

Microelements are common in the earth's crust in concentrations not exceeding 0.1%, and in living matter they are found in quantities of 10 -3 -10 -12%. The group of trace elements includes metals, non-metals, and halogens. Their only common feature is their low content in living tissues.

Microelements take an active part in many life processes occurring in plants at the molecular level. By influencing the enzyme system or in direct connection with plant biopolymers, they stimulate or inhibit the occurrence of physiological processes in tissues.

To adjust the content of microelements in the soil, foliar feeding is practiced during the growing season, pre-sowing treatment of seeds and planting material, as well as the introduction of necessary substances into the soil in the form of fertilizers.

Physical and chemical properties

Microelements differ in their physical and chemical properties. Among them there are metals (,), nonmetals (), halogens ().

Classification of trace elements

Chemical elements are divided into those necessary for plants and those useful to them.

Required

nutritional elements meet the following requirements:

• without the element the plant’s life cycle cannot be completed;
• physiological functions performed with the participation of a specific element are not carried out when it is replaced by another element;
• the element is necessarily involved in plant metabolism.

However, there are a number of conventions in using this term. The fact is that difficulties with its use arise when comparing the need for one or another element for the life of higher and lower plants and, especially, animals and humans. For example, the need for boron for some fungi has not been proven; the need for cobalt to carry out the physiological functions of a number of plants is controversial. The undeniably necessary elements include chlorine and nickel.

Useful

- these are nutritional elements that have the ability to stimulate the growth and development of plants, but do not fully meet the three requirements given above. This group also includes those elements that are necessary only in certain conditions and only for certain types of plants. Currently, selenium, silicon, aluminum, and others are considered beneficial for plants.

Currently, only about ten microelements are considered vital for plants, and several more are considered necessary for a narrow range of species. For the remaining elements, it is known that they can have a stimulating effect on plants, but their functions have not been established.

Some physical and chemical properties of trace elements, according to:
Microelement	Atomic number	Atomic mass					Physical condition under normal conditions
		10,81		non-metal	3700	2075	black powder
		50,94		metal	3400	1900	silver metal
		126,90		halogen	113,6	185,5	black and purple crystals
		54,94		metal	2095	1244	silver white metal
		59,93	VIII	metal	2960	1494	hard, malleable, shiny metal
		63,54		metal	2600	1083	red metal, pink when broken
		65,39		metal		419,5	bluish-silver metal
		95,94		metal	4800	2620	light gray metal

Microelements are found in small quantities almost everywhere: in rocks, soil, plants and, naturally, in the body of humans and animals.

Sod-

podzolic

1,5-6 ,6

0,08-0,38

0,1-47,9

0,05-5,0

20-67

0,12-20,0

40-7200

50,0-150

1,0-4,0

0,04-0 ,97

0,45-14,0

0,12-3,0

10-62

n.d.

0,5-4,4

n.d.

Chernozem

4-12

0,38-1,58

7-18

4,5-10,0

24-90

0,10-0,25

200-5600

1,0-75

0,7-8,6

0,02-0,33

2,6-13,0

1,10-2,2

37-125

n.d.

2,0-9,8

n.d.

Serozem

8,8-160,3

0,23-0,62

5-20

2,5-10,0

26-63

0,09-1,12

310-3800

1,5-125

0,7-2,0

0,03-0,15

n.d.

0,9-1,5

50-87

n.d.

1,3-38

n.d.

Chestnut

100-200

0,30-0,90

0,6-20

8,0-14,0

0,06-0,14

600-1270

1,5-75

0,2-2,0

0,09-0,62

0,1-6,0

n.d.

2,0-9,8

n.d.

Buraya

40,5

0,38-1,95

14-44,5

6,0-12,0

32,5-54,0

0,03-0,20

390-580

1,5-75

0,4-2,8

0,06-0,12

2,3-3,8

0,57-2,25

n.d.

0,3-5,3

n.d.

Role in the plant

Biochemical functions

The role of microelements for plants is multifaceted. They are designed to improve metabolism, eliminate functional disorders, promote the normal course of physiological and biochemical processes, and influence the processes of photosynthesis and respiration. Under the influence of microelements, plant resistance to bacterial and fungal diseases, adverse environmental factors (drought, increased or decreased temperature, heavy wintering, etc.) increases.

It has been established that microelements are part of a large number of enzymes that play an important role in plant life. All biochemical reactions of synthesis, decomposition, and metabolism of organic substances occur only with the participation of enzymes.

,

as part of microfertilizers, they increase the activity of peroxidase and polyphenoloxidase enzymes in both cotyledons and pea roots, but do not change their activity in seedlings. At the same time, in both peas and corn, the peroxidase oxidative system predominates over the polyphenoloxidase system.

Role in the plant and the main functions of some essential micronutrients, according to:
Microelement	What components does it include?	Processes in which it participates
	Phosphogluconates	Metabolism and transport of carbohydrates, Synthesis of flavonoids, Synthesis of nucleic acids, Phosphate utilization, formation of polyphenols.
	Coenzyme cobamide	Symbiotic nitrogen fixation (possibly in non-nodule plants), stimulation of redox reactions during the synthesis of chlorophyll and proteins.
	Various oxidants, plastocyanins, cenoplasmin.	Oxidation, photosynthesis, protein and carbohydrate metabolism, Possibly involved in symbiotic nitrogen fixation and redox reactions.
	Tyrosine and its derivatives in angiosperms and algae
	Many enzyme systems	Photoproduction of oxygen in chloroplasts and indirect participation in the reduction of NO 3 -
	Nitrate reductase, nitrogenase, oxidases and molybdenoferridoxin	Nitrogen fixation, NO 3 reduction - Redox reactions
	Porphins, hemoproteins	Lipid metabolism, photosynthesis in green algae and possible participation in N2 fixation
	Anhydrases, dehydrogenases, proteinases and peptidases	Metabolism of carbohydrates and proteins

Lack (deficiency) of microelements in plants

If there is insufficient intake of any microelement from among essential nutrients plant growth deviates from normal or stops altogether, and further development of the plant, especially its metabolic cycles, is disrupted.

With a lack of microelements, the activity of many enzymes decreases sharply. For example, it has been found that with a lack of copper, the activity of enzymes that contain copper, namely polyphenol oxidase and ascorbate oxidase, sharply decreases.

Symptoms of insufficiency (deficiency) are difficult to reduce to one denominator, but, nevertheless, they are characteristic of specific microelements. Chlorosis is most often observed.

Visual symptoms are very important for diagnosing deficiency, but disturbances in metabolic processes and, as a consequence, loss of biomass production may occur before symptoms of deficiency are noticeable. To improve methods for diagnosing micronutrient deficiency, a number of authors propose biochemical indicators. Unfortunately, the widespread use of this method is limited due to the large variability of enzymatic activity and the difficulty of determining this indicator.

The most widely used tests are soil and plant analysis. But even in this case, immobile forms of trace elements located in old parts of the plant can distort the data. However, analysis of plant tissues has been successfully used to establish micronutrient deficiencies by comparison with the content of these compounds in the same tissues of normal plants of the same age and in the same organs.

When eliminating a deficiency of microelements with the help of fertilizers, one should take into account the fact that such a procedure is effective only if the content of the element in the soil or its availability is sufficiently low.

In any case, the formation of micronutrient deficiency in plants is the result of a complex interaction of several factors. Numerous observations have proven that the properties and genesis of soils are the main reasons causing a deficiency of microelements in the plant. Typically, a lack of microelements is associated with highly acidic soils (light sandy) and alkaline (calcareous) soils with an unfavorable water regime, as well as an excess of phosphates, nitrogen, calcium, iron and manganese oxides.

Symptoms of micronutrient deficiency nutrition in agricultural crops, according to:
Element	Symptoms	Sensitive toculture
	Chlorosis and browning of young leaves, Dead apical buds, Disturbance of flower development, Damage to the core of plants and roots, Animation during cell division	Cabbage and related species, Celery, Grape, Fruit trees (pear and apple trees)
	Melanism, White curled tops, Reducing the formation of panicles, Violation of lignification	Cereals (oats), Sunflower,
	Chlorosis spots, Necrosis of young leaves, Weakened turgor	Cereals (oats), Fruit trees (apple, cherry, citrus)
	Chlorosis of the edge of the leaf blade, Cauliflower clotting disorder Fiery edges and deformed leaves, Destruction of embryonic tissues.	Cabbage, related species,
	Interveinal chlorosis (in monocots), Stopping growth Rosette leaves on trees Purple-red dots on leaves	Cereals (corn), Grape, Fruit trees (citrus).

Excess of trace elements in plants

Metabolic disorders in plants are caused not only by a deficiency, but also by an excess of nutrients. Plants are more resistant to increased rather than decreased concentrations of microelements.

The main reactions associated with the toxic effects of trace elements:

• changes in cell membrane permeability;
• reactions of thiol groups with cations;
• competition with vital metabolites;
• high affinity for phosphate groups and active centers in ADP and ATP;
• capture of positions in molecules occupied by vital groups, such as phosphate and nitrate.

Assessing the effect of toxic concentrations of elements on a plant is quite complex, since it depends on many factors. The most important are the proportions in which ions and their compounds are present in the soil solution.

For example, the toxicity of arsenate and selenate decreases markedly with an excess of sulfate and phosphate. Organometallic compounds can be more toxic than cations of the same element. Oxygen anions of elements are generally more toxic than their simple cations.

The most toxic to higher plants are, nickel, lead, .

Visible symptoms of toxicity vary depending on the plant species, but there are also general, non-specific symptoms of phytotoxicity: chlorotic and brown spots on leaf blades and their edges, as well as brown, stunted roots of a coral-like configuration.

Symptoms of Micronutrient Toxicity in common agricultural crops, according to:
Element	Symptoms	Sensitive crops
	Chlorosis of the edges and ends of leaves, Brown spots on leaves Rotting of growth points, Curling and dying of old leaves	Potato, Tomatoes, Sunflower,
	White edges and tips of leaves, Ugly root tips	Potato, Tomatoes, Sunflower,
	Dark green leaves Roots are thick, short or barbed wire-like, Inhibition of shoot formation	Citrus seedlings, Gladioli
	Chlorosis and necrotic lesions on old leaves, Brownish-black or red necrotic spots, Accumulation of manganese oxide particles in epidermal cells, Dried tips of leaves Stunted roots	Potato,
	Yellowing or browning of leaves, Root growth inhibition Tillering inhibition		Chlorosis and necrosis of leaf tips, Interveinal chlorosis of young leaves, Stunted growth of the plant as a whole, The roots are damaged and look like barbed wire.

Content of microelements in various compounds

Microfertilizers are fertilizers in which the active ingredient is one (or more) microelements. They can be presented both in the form of mineral forms and organomineral compounds. Microfertilizers are classified according to the main element they contain (manganese, zinc, copper-containing, etc.).

Microelements can also be included in macrofertilizers in the form of impurities. A certain amount of microelements is added to the soil and as part of organic fertilizers. In practice, waste from various industries enriched with microelements is often used as microfertilizers.

Methods of using microfertilizers and fertilizers containing microelements

Microfertilizers are used for soil application, foliar feeding and pre-planting seed treatment. Doses of microfertilizers are small. This requires high dosing accuracy and uniformity of application.

Application to the soil

used to radically increase the content of microelements in the soil throughout the growing season. With this method, negative effects may be observed:

• formation of poorly soluble forms of microelements,
• leaching of microelements beyond the root layer.

It is not recommended to apply expensive types of microfertilizers to the soil, especially in the fall. In this case, it is better to use various macrofertilizers modified with microelements, hard-to-reach industrial waste and long-acting fertilizers.

Pre-sowing seed treatment

- the most common way to use microfertilizers. This method is technologically advanced and allows you to combine seed treatment with sowing. It is this form of processing that helps optimize the plant’s nutrition with microelements at the earliest stages of development. Often, seed treatment with microelements is combined with the use of film-forming substances, growth regulators and disinfectants. This process is called seed encrustation.

Foliar feeding

It is recommended to carry out when a microelement deficiency is directly detected. This method allows you to adjust the nutrition of plants with microelements, avoiding the negative consequences of introducing microfertilizers into the soil.

This is a group of chemical elements found in human or animal organs in small quantities.

The daily requirement for them is expressed in milligrams or milligram particles. They have high biological activity and are necessary for the life of the body. These elements include iron, copper, cobalt, nickel, iodine, manganese, fluorine, zinc, chromium.

A lack of these substances in products can lead to structural and functional changes in the body, and their excess has a toxic effect.

Main characteristics of microelements

Iron.

Found in hemoglobin in the blood, it takes part in oxidative-renewal processes, is part of enzymes, and stimulates intracellular metabolism.

Iron is found in liver, kidneys, rabbit meat, eggs, buckwheat, wheat groats, legumes, apples, peaches.

Copper.

Necessary for the synthesis of hemoglobin, enzymes, proteins, promotes the normal functioning of the endocrine glands, the production of insulin, adrenaline.

Copper is found in liver, seafood, buckwheat and oatmeal, and nuts.

Cobalt.

Activates the processes of creating red blood cells in hemoglobin, affects the activity of certain elements, takes part in the production of insulin, and is necessary for the synthesis of vitamin B.

Cobalt is found in sea plants, peas, beet, black currants, and strawberries.

It takes part in the creation of thyroid hormones - thyroxine, which controls the state of energy metabolism, actively influences physical and psychological development, the metabolism of proteins, fats, carbohydrates, water-salt metabolism. A lack of iodine in the human body leads to an increase in the amount of thyroglobulin, and this sharply reduces the function of the sex glands and causes mental retardation. As a result, the iron increases and a disease called goiter occurs.

In Ukraine, in the western regions far from the sea, according to the Institute of Endocrinology, 30% of children suffer from goiter; they lag behind in mental, physical and sexual development. In total, 1.5 million people in the country suffer from goiter.

Found in sea water, seafood - fish, seaweed.

Manganese.

Takes part in the creation of cells, blood circulation, functions of the endocrine system, vitamin metabolism, and in stimulating growth processes.

Manganese is found in cereals and legumes, coffee, and nuts.

Fluorine.

Takes part in the development of teeth, the creation of cells, normalizes phosphorus-calcium metabolism.

Found in fish, lamb, veal, oatmeal, and nuts.

Zinc.

It is part of many enzymes, insulin, takes part in blood circulation, the synthesis of amino acids, is necessary for the normal functioning of the endocrine glands, and normalizes fat metabolism.

Found in liver, meat, egg yolk, mushrooms, cereals, legumes, garlic, potatoes, beet, nuts.

Chromium.

Takes part in the regulation of carbohydrates and mineral metabolism, cholesterol metabolism, and activates some enzymes.

Chromium is found in beef, liver, poultry, grains, legumes, pearl barley, and barley flour.

17. Metabolism and energy during nutrition

The life processes of an organism are associated with the constant absorption of substances in the environment and the release of final decay products into the same environment.

The set of chemical transformations in organisms that ensure their growth, vital activity and reproduction is called metabolism (metabolism).

It occurs between living organisms and the environment. Metabolism is inherent in both living and inanimate nature. However, there is a fundamental difference between them in the process of metabolism of nonliving bodies; the latter are certainly destroyed, while the metabolism of living organisms and the environment creates the basis for their existence.

Metabolism is based on 2 (two) interconnected processes of synthesis (anabolism) and breakdown (catabolism).

First– assimilation (anabolism); plastic metabolism (assimilation of substances and synthesis of compounds specific to each tissue).

Second– dissimilation (catabolism); energy metabolism (enzymatic breakdown of organic substances and release of decay products from the body).

Metabolism of substances and energy in the cell is carried out in the form of:

Plastic metabolism (assimilation, anabolism), i.e., a set of biosynthesis reactions (the creation of substances occurs with the absorption of energy);

Energy metabolism (dissimilation, catabolism), i.e., a set of reactions of the breakdown of substances and the release of energy.

As a result of the processes of dissimilation of food products, seedling products and energy are created, which ensures the progress of assimilation processes. The interaction of these processes ensures the existence of the organism.

Metabolism is based on a large number of chemical reactions that occur in a certain sequence and are closely related to the arc. These reactions are catalyzed by enzymes and are controlled by the nervous system. Metabolism can be roughly divided into external exchange, which involves finding nutrients in the body and removal of end products of decomposition, and internal exchange, which converts all nutrient changes into the body's cells.

What chemical elements are classified as microelements and what are their functions in the human body?

Microelements - contained in small quantities (in units of mg or less). These include:

Undoubtedly recognized microelements - the deficiency of which in the diet causes specific manifestations of metabolic disorders and clinical symptoms of deficiency in humans. These microelements can be considered irreplaceable (essential) micronutrients, the need for which is determined to one degree or another. Of course, iron, copper, manganese, zinc, cobalt, iodine, fluorine, chromium, molybdenum and selenium are recognized.

Conventionally recognized microelements are those whose deficiency in the diet caused certain disorders in experimental animals. In humans, manifestations of deficiency of these microelements have not yet been established, although they cannot be excluded. Currently, the need for conventionally recognized microelements is tentative. Vanadium, nickel, strontium, silicon, and boron are conventionally recognized.

The importance of minerals for the body is extremely diverse. Main functions of minerals:

plastic function, especially in the construction of bone tissue;

regulation of water-salt metabolism;

maintaining osmotic pressure in cells and intercellular fluids, which is necessary for the movement of nutrients and metabolic products between them;

protective functions (participation in immunity);

are part of or activate the action of enzymes, hormones, vitamins and thus participate in all types of metabolism;

participation in the processes of hematopoiesis and blood coagulation - they cannot occur without iron, copper, manganese, calcium and other mineral elements.

The normal function of the nervous, cardiovascular, digestive and other systems is impossible without minerals.

Long-term deficiency or excess of minerals in the body leads to various metabolic disorders and diseases.

Iron is necessary for normal hematopoiesis and tissue respiration. It is part of the hemoglobin of erythrocytes, which delivers oxygen to organs and tissues, muscle myoglobin, enzymes involved in the transfer of electrons through the respiratory chain and redox processes.

Iodine. The body of a healthy adult contains about 15-20 mg of iodine, 80% of which is found in the thyroid gland. The biological significance of iodine lies in its participation in the formation of thyroid hormones - thyroxine (T4) and triiodothyronine (T3), which are 65 and 59% iodine, respectively.

Fluorine, together with calcium and phosphorus, is involved in the construction of bones and teeth and ensures their hardness and strength. A lack of fluoride in water and food products contributes to the development of dental caries and a decrease in bone strength, while an excess leads to fluorosis (bone damage, mottling of tooth enamel, brittle teeth). A special feature of fluorine is the narrow upper and lower limits of its positive effect on the body. If drinking water contains less than 0.5 mg of fluoride per liter (0.5 mg/l), dental caries may occur, if more than 1.5-2 mg/l (according to some data, more than 1.2 mg/l ) - fluorosis.

Zinc is part of more than 200 enzymes involved in a wide variety of metabolic reactions. It is necessary for the activity of the gonads, pituitary gland, and adrenal glands; is an integral part of the pancreatic hormone - insulin. Zinc ensures normal hematopoiesis and bone formation, maintaining the immune status of the body. It helps stabilize cell membranes and is an antioxidant protection factor.

Copper. The adult human body contains about 150 mg of copper, of which 15-20 mg is in the liver, and the rest in other organs and tissues. The biological role of copper is associated with its participation in the construction of approximately 25 enzymes. Copper is part of cytochrome oxidase, monoamine oxidase, tyrosinase, superoxy-dismutase and other vital enzymes. As part of the ceruloplasmin protein, copper is involved in the oxidation of catecholamines, serotonin and other aromatic amines, as well as in the oxidation of ferrous iron into ferric iron, which can bind to transferrin and thus be transported to organs and tissues. Copper is considered a hematopoietic element involved in the formation of hemoglobin and red blood cells.

Selenium is one of the key micronutrients of the body's antioxidant system. It is part of glutathione peroxidases and other enzymes. Selenium and vitamin E are considered synergists. Selenium has a positive effect on the immune system, increases resistance to radiation exposure, and is involved in maintaining the function of the thyroid gland and reproductive organs. Selenium is especially characterized by a dose-dependence of action: on the one hand, its toxicity and carcinogenicity have been identified, on the other, its therapeutic activity and anticarcinogenicity.

Chromium. The human body contains predominantly trivalent chromium compounds. Hexavalent chromium salts have no physiological significance and, according to some data, are extremely toxic to humans. The adult body contains less chromium than other microelements (6-12 mg). A significant portion of chromium (up to 2 mg) is concentrated in the skin, as well as in bones and muscles. With age, the chromium content in the body, unlike other trace elements, progressively decreases.

The importance of manganese, molybdenum, cobalt and conditionally essential microelements such as silicon, vanadium, strontium, boron, and nickel for the normal metabolism and vital functions of the body has been established. The content of these microelements in food products is usually sufficient to meet the body's needs. In this regard, in humans (unlike some animals, including experimental ones), diseases caused by a deficiency of these microelements practically do not occur.

1. In which group do all elements belong to macroelements? To microelements?

a) Iron, sulfur, cobalt; b) phosphorus, magnesium, nitrogen; c) sodium, oxygen, iodine; d) fluorine, copper, manganese.

Macroelements include: b) phosphorus, magnesium, nitrogen.

Microelements include: d) fluorine, copper, manganese.

2. What chemical elements are called macroelements? List them. What is the importance of macronutrients in living organisms?

Macroelements are chemical elements whose content in living organisms is more than 0.01% (by weight). Macroelements are oxygen (O), carbon (C), hydrogen (H), nitrogen (N), calcium (Ca), phosphorus (P), potassium (K), sulfur (S), chlorine (Cl), sodium (Na ) and magnesium (Mg). For plants, silicon (Si) is also a macronutrient.

Carbon, oxygen, hydrogen and nitrogen are the main components of organic compounds of living organisms. In addition, oxygen and hydrogen are part of water, the mass fraction of which in living organisms averages 60-75%. Molecular oxygen (O2) is used by most living organisms for cellular respiration, during which the energy necessary for the body is released. Sulfur is part of proteins and some amino acids, phosphorus is part of organic compounds (for example, DNA, RNA, ATP), components of bone tissue, and tooth enamel. Chlorine is part of the hydrochloric acid in the gastric juice of humans and animals.

Potassium and sodium are involved in the generation of bioelectric potentials and ensure the maintenance of the normal rhythm of cardiac activity in humans and animals. Potassium is also involved in the process of photosynthesis. Calcium and magnesium are part of bone tissue and tooth enamel. In addition, calcium is necessary for blood clotting and muscle contraction, it is part of the cell wall of plants, and magnesium is part of chlorophyll and a number of enzymes.

3. What elements are called microelements? Give examples. What is the role of microelements for the life of organisms?

Microelements are called vital chemical elements, the mass fraction of which in living organisms is 0.01% or less. This group includes iron (Fe), zinc (Zn), copper (Cu), fluorine (F), iodine (I), manganese (Mn), cobalt (Co), molybdenum (Mo) and some other elements.

Iron is part of hemoglobin, myoglobin and many enzymes, and is involved in the processes of cellular respiration and photosynthesis. Copper is part of hemocyanins (respiratory pigments in the blood and hemolymph of some invertebrate animals), participates in the processes of cellular respiration, photosynthesis, and hemoglobin synthesis. Zinc is part of the hormone insulin, some enzymes, and is involved in the synthesis of phytohormones. Fluorine is part of tooth enamel and bone tissue, iodine is part of thyroid hormones (triiodothyronine and thyroxine). Manganese is part of a number of enzymes or increases their activity, participates in the formation of bones, and in the process of photosynthesis. Cobalt is necessary for hematopoietic processes and is part of vitamin B12. Molybdenum is involved in the processes of binding molecular nitrogen (N 2) by nodule bacteria.

4. Establish a correspondence between a chemical element and its biological function:

1 – d (calcium is necessary for muscle contraction and blood clotting);

2 – c (magnesium is a component of chlorophyll);

3 – e (cobalt is part of vitamin B 12);

4 – b (iodine is part of thyroid hormones);

5 – a (zinc is involved in the synthesis of plant hormones and is part of insulin);

6 – g (copper is part of the hemocyanins of some invertebrate animals).

5. Based on the material about the biological role of macro- and microelements and the knowledge gained from studying the human body in the 9th grade, explain what consequences a lack of certain chemical elements in the human body can lead to.

For example, with a lack of calcium, the condition of the teeth worsens and caries develops, there is an increased tendency of bones to deform and fracture, cramps appear, and blood clotting decreases. Lack of potassium leads to the development of drowsiness, depression, muscle weakness, and cardiac arrhythmia. With iron deficiency, a decrease in hemoglobin levels is observed, and anemia (anemia) develops. If there is insufficient intake of iodine into the body, the synthesis of triiodothyronine and thyroxine (thyroid hormones) is disrupted, an enlargement of the thyroid gland in the form of a goiter may be observed, fatigue develops, memory deteriorates, attention decreases, etc. Long-term iodine deficiency in children can lead to delays in physical and mental development. With a lack of cobalt, the number of red blood cells in the blood decreases. Fluoride deficiency can cause tooth decay, tooth loss, and gum damage.

6. The table shows the content of the main chemical elements in the earth’s crust (by mass, in %). Compare the composition of the earth's crust and living organisms. What are the features of the elemental composition of living organisms? What facts allow us to draw a conclusion about the unity of living and inanimate nature?

Element	Content, %	Element	Content, %	Element	Content, %
Oxygen	49,13	Sodium	2,4	Carbon	0,35
Silicon	26	Magnesium	2,35	Chlorine	0,2
Aluminum	7,45	Potassium	2,35	Phosphorus	0,125
Iron	4,2	Hydrogen	1	Sulfur	0,1
Calcium	3,25	Titanium	0,61	Nitrogen	0,04

Living organisms are more than 98% (by mass) composed of four elements - oxygen (O), carbon (C), hydrogen (H) and nitrogen (N). In the earth's crust, the total mass fraction of these elements is slightly more than 50%. At the same time, both in the composition of the earth’s crust and in living organisms, the predominant chemical element is oxygen. However, the share of the three remaining elements (C, H and N), necessary for the construction of molecules of organic substances, in the composition of living organisms accounts for more than 28%, and in the earth’s crust their total content does not reach 1.5%. On the other hand, some chemical elements that are widespread in the earth's crust (silicon, aluminum, iron) are contained in very small quantities by living organisms.

Living organisms contain the same chemical elements that make up inanimate objects, only in a different ratio. For living organisms, the initial (primary) sources of these elements are substances that make up the atmosphere, hydrosphere and lithosphere - H 2 O, CO 2, O 2, N 2, various ions, etc. Chemical elements are returned to the environment during the life of organisms (respiration, excretion) and after their death. This testifies to the unity and interconnection of living and inanimate nature.