The "biological role of chemical elements" project. Functions of chemical elements in the human body

>> Chemistry: Chemical elements in the cells of living organisms

More than 70 elements have been found in the composition of substances that form the cells of all living organisms (humans, animals, plants). These elements are usually divided into two groups: macronutrients and micronutrients.

Macronutrients are found in cells in large quantities... First of all, these are carbon, oxygen, nitrogen and hydrogen. In total, they make up almost 98% of the total cell content. In addition to these elements, the macronutrients also include magnesium, potassium, calcium, sodium, phosphorus, sulfur and chlorine. Their total content is 1.9%. Thus, the share of other chemical elements is about 0.1%. These are trace elements. These include iron, zinc, manganese, boron, copper, iodine, cobalt, bromine, fluorine, aluminum, etc.

23 microelements have been found in mammalian milk: lithium, rubidium, copper, silver, barium, strontium, titanium, arsenic, vanadium, chromium, molybdenum, iodine, fluorine, manganese, iron, cobalt, nickel, etc.

The mammalian blood contains 24 microelements, and the human brain contains 18 microelements.

As you can see, there are no special elements in the cell that are characteristic only of living nature, that is, at the atomic level there are no differences between living and inanimate nature. These differences are found only at the level of complex substances - at molecular level... So, along with inorganic substances (water and mineral salts), the cells of living organisms contain substances that are characteristic only of them - organic substances (proteins, fats, carbohydrates, nucleic acids, vitamins, hormones, etc.). These substances are built mainly from carbon, hydrogen, oxygen and nitrogen, that is, from macronutrients. Trace elements are contained in these substances in insignificant quantities, however, their role in the normal life of organisms is enormous. For example, compounds of boron, manganese, zinc, cobalt sharply increase the productivity of individual agricultural plants and increase their resistance to various kinds of diseases.

Man and animals receive the trace elements they need for normal life through the plants they feed on. If there is not enough manganese in food, then growth retardation, a slowdown in the onset of puberty, metabolic disorders during the formation of the skeleton are possible. The addition of fractions of a milligram of manganese salts to the daily ration of animals eliminates these diseases.

Cobalt is part of vitamin B12, which is responsible for the work of the blood-forming organs. Lack of cobalt in food often causes serious illness, which leads to depletion of the body and even death.

The importance of trace elements for humans was first revealed in the study of a disease such as endemic goiter, which was caused by a lack of iodine in food and water. Taking salt containing iodine leads to recovery, and adding it to food in small amounts prevents disease. For this purpose, food table salt is iodized, to which 0.001-0.01% of potassium iodide is added.

Most biological enzyme catalysts contain zinc, molybdenum, and some other metals. These elements, contained in the cells of living organisms in very small quantities, ensure the normal functioning of the finest biochemical mechanisms, are true regulators of vital processes.

Many trace elements are found in vitamins - organic matter ah of various chemical nature, entering the body with food in small doses and having a great impact on the metabolism and general vital functions of the body. In their own way biological action they are close to enzymes, but enzymes are produced by the cells of the body, and vitamins are usually taken from food. Sources of vitamins are plants: citrus fruits, rose hips, parsley, onions, garlic and many others. Some vitamins - A, B1, B2, K - are obtained synthetically. Vitamins got their name from two words: vita - life and amine - containing nitrogen.

Trace elements are also part of hormones - biologically active substances that regulate the work of organs and systems of human and animal organs. They take their name from the Greek word harmao - I conquer. Hormones are produced by the endocrine glands and enter the bloodstream, which carries them throughout the body. Some hormones are produced synthetically.

1. Macronutrients and microelements.

2. The role of trace elements in the life of plants, animals and humans.

3. Organic matter: proteins, fats, carbohydrates.

4. Enzymes.

5. Vitamins.

6. Hormones.

At what level of forms of existence of a chemical element does the difference between living and inanimate nature begin?

Why are individual macronutrients also called biogenic? List them.

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

What is a cage?

It is the basic structural unit of living things. She has her own metabolism. A cell can also exist as an independent organism: an example of this is ciliates, amoeba, chlamydomonas, etc. This structure consists of a variety of substances, both organic and inorganic. Everything chemical substances cells play a specific function in its structure and metabolism.

Chemical elements

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

Oxygen

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

Carbon

This element, like hydrogen, is found in all organic substances. The chemical composition of the cell includes about 15-18 percent. Carbon in the form of CO is involved in the regulation of cellular functions; it also participates in photosynthesis in the form of CO 2.

Hydrogen

This element in the cell contains approximately 8-10 percent. Most of it is found in water molecules. Molecular hydrogen is oxidized by the cells of some bacteria for energy synthesis.

Potassium

The chemical composition of the cell includes about 0.15-0.4% of this chemical element. He performs very important role participating in the processes of generating a nerve impulse. That's why to strengthen nervous system it is recommended to use preparations containing potassium. Also, this element helps to maintain the membrane potential of the cell.

Phosphorus

The amount of this element in the composition of the cell is equal to 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. Its high concentration is observed in the cells of muscle and bone tissue. Besides, inorganic compounds containing 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 found 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 low concentration, it is present in the cytoplasm and intercellular substance in the form of ions.

Chlorine

Contains in the amount of 0.05-0.1%. Maintains cell electroneutrality.

Sodium

This element is present in the composition of the cell in an 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 release of certain substances from it (hormones, proteins, etc.)

Magnesium

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

Iron

The amount of this element is 0.01-0.015%. However, there is much more of it in erythrocytes, since it is the basis of hemoglobin.

Zinc

It is found in insulin as well as in many enzymes.

Copper

This element is one of the components of oxidative enzymes that are involved in the synthesis of cytochromes.

Squirrels

These are the most complex compounds in the cell, the main substances of which it is composed. They consist of amino acids, connected in a certain order in a chain, and then twisted into a ball, the shape of which is specific for each type of protein. These substances perform many important functions in the life of the cell. One of the most important is the enzymatic function. Proteins act as natural catalysts to speed up the process chemical reaction hundreds of thousands of times - splitting and synthesis of any substances is impossible without them. Each type of enzyme is involved in only one specific reaction and cannot enter into another. Proteins also have a protective function. Substances of this group, which protect the cell from the ingress of foreign proteins into it, are called antibodies. These substances also protect the entire body from disease-causing viruses and bacteria. In addition, these connections perform a transport function. It lies in the fact that there are transporter proteins in the membranes that carry certain substances outside or inside the cell. The plastic function of these substances is also very important. They are the main building material, of which the cell, its membranes and organelles are composed. Sometimes proteins also carry out an energy function - with a lack of fats and carbohydrates, the cell breaks down these substances.

Lipids

This group of substances includes fats and phospholipids. The first are the main source of energy. They can also accumulate as reserve substances in case of starvation. The latter serve as the main constituent of cell membranes.

Carbohydrates

The most common substance in this group is glucose. She and similar simple carbohydrates perform an energy function. Also carbohydrates include polysaccharides, the molecules of which consist of thousands of combined molecules - monosaccharides. They mainly play a structural role as part of membranes. The main polysaccharides of plant cells are starch and cellulose, animals - glycogen.

Nucleic acids

To this group chemical compounds includes DNA, RNA and ATP.

DNA

This substance performs an essential function - it is responsible for the storage and hereditary transmission of genetic information. DNA is found in the chromosomes of the nucleus. Macromolecules of this substance are formed from nucleotides, which, in turn, consist of a nitrogenous base, represented by purines and pyrimidines, a hydrocarbon and phosphoric acid residues. They are of four types: adenyl, guanyl, thymidyl and cytidyl. The name of the nucleotide depends on what purines are in its composition, it can be adenine, guanine, thymine and cytosine. The DNA molecule has the form of two strands twisted into a spiral.

RNA

This connection performs the function of realizing the information that is in DNA through the synthesis of proteins, the composition of which is encrypted. This substance is very similar to the nucleic acid described above. Their main difference is that RNA consists of one strand, not two. Also, the composition of RNA nucleotides includes the nitrogenous base of uracil instead of thymine and ribose. That's why this substance is formed from nucleotides such as adenyl, guanyl, uridyl and cytidyl.

ATF

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

1. Give definitions of concepts.
Element- a set of atoms with the same nuclear charge and the number of protons, which coincides with the ordinal (atomic) number in the periodic table.
Trace element - an element that is found in very low concentrations in the body.
Macronutrient - an element that is found in high concentrations in the body.
Bioelement- a chemical element participating in the life of a cell is the basis of biomolecules.
Elemental composition of the cell - the percentage of chemical elements in the cell.

2. What is one of the proofs of the commonality of animate and inanimate nature?
Unity of chemical composition. There are no elements characteristic only of inanimate nature.

3. Complete the table.

ELEMENTAL COMPOSITION OF THE CELL

4. Give examples of organic substances, the molecules of which consist of three, four and five macronutrients.
3 elements: carbohydrates and lipids.
4 elements: proteins.
5 elements: nucleic acids, proteins.

5. Fill in the table.

BIOLOGICAL ROLE OF ELEMENTS

6. Study in § 2.2 the section "The role of external factors in the formation of the chemical composition of living nature" and answer the question: "What are biochemical endemics, and what are the reasons for their origin?"
Biochemical endemics are diseases of plants, animals and humans, caused by a sharp deficiency or excess of any element in a certain area.

7. What diseases do you know associated with micronutrient deficiencies?
Iodine deficiency is an endemic goiter. A decrease in the synthesis of thyroxine and the growth of thyroid tissue as a result.
Iron deficiency - iron deficiency anemia.

8. Remember on what basis chemical elements are divided into macro-, micro- and ultramicroelements. Suggest your own, alternative classification of chemical elements (for example, according to their functions in a living cell).
Micro-, macro- and ultramicroelements are divided according to the characteristic based on their percentage in the cell. In addition, it is possible to classify the elements according to the functions that regulate the activity of certain organ systems: nervous, muscular, circulatory and cardiovascular, digestive, etc.

9. Choose the correct answer.
Test 1.
What chemical elements are the majority of organic substances formed by?
2) C, O, H, N;

Test 2.
Macronutrients do not include:
4) manganese.

Test 3.
Living organisms need nitrogen, as it serves:
1) an integral component of proteins and nucleic acids; 10. Determine the attribute by which all of the following elements, except for one, are combined into one group. Underline this "extra" element.
Oxygen, hydrogen, sulfur, iron, carbon, phosphorus, nitrogen. Only DNA is included. And the rest are all in proteins.

11. Explain the origin and total value words (term), based on the meaning of the roots that make it up.

12. Choose a term and explain how much it is modern meaning corresponds to the original meaning of its roots.
Selected term- organogen.
Correspondence: the term, in principle, corresponds to its original meaning, but today there is a more precise definition. Previously, the meaning was such that the elements take part only in the construction of tissues and cells of organs. Now it has been found that biologically important elements not only form chemical molecules in cells, etc., but also regulate all processes in cells, tissues and organs. They are found in hormones, vitamins, enzymes and other biomolecules.

13. Formulate and write down the main ideas § 2.2.
The elemental composition of a cell is the percentage of chemical elements in the cell. Cell elements are usually classified, depending on their percentage, into micro-, macro- and ultramicroelements. Those elements that are involved in the life of the cell, form the basis of biomolecules, are called bioelements.
Macronutrients include: C N H O. They are the main components of all organic compounds in the cell. In addition, P S K Ca Na Fe Cl Mg - are part of all the most important biomolecules. The functioning of the body is impossible without them. Lack of them leads to death.
To trace elements: Al Cu Mn Zn Mo Co Ni I Se Br F B, etc. They are also necessary for the normal functioning of the body, but not so critical. Lack of them causes illness. They are part of biologically active compounds, affect metabolism.
There are ultramicroelements: Au Ag Be and others. The physiological role has not been finally established. But they are important for the cell.
There is the concept of "biochemical endemics" - diseases of plants, animals and humans, caused by a sharp deficiency or excess of any element in a certain area. For example, endemic goiter (iodine deficiency).
With a lack of an element due to the diet, illness or malaise may also occur. For example, with a lack of iron - anemia. With a lack of calcium - frequent fractures, loss of hair, teeth, muscle pain.

Cell

From the point of view of the concept of living systems according to A. Lehninger.

A living cell is an isothermal system of organic molecules capable of self-regulation and self-reproduction, extracting energy and resources from the environment.

The cell is running a large number of sequential reactions, the speed of which is regulated by the cell itself.

The cell maintains itself in a stationary dynamic state, far from equilibrium with the environment.

Cells function according to the principle of minimum consumption of components and processes.

That. a cell is an elementary living open system capable of independent existence, reproduction and development. It is an elementary structural and functional unit of all living organisms.

Chemical composition cells.

Of the 110 elements of the periodic system of Mendeleev, 86 are found constantly present in the human body. 25 of them are necessary for normal life, and 18 of them are absolutely necessary, and 7 are useful. In accordance with the percentage in the cell, chemical elements are divided into three groups:

Macronutrients The main elements (organogens) are hydrogen, carbon, oxygen, nitrogen. Their concentration: 98 - 99.9%. They are universal components of organic compounds of the cell.

Trace elements - sodium, magnesium, phosphorus, sulfur, chlorine, potassium, calcium, iron. Their concentration is 0.1%.

Ultramicroelements - boron, silicon, vanadium, manganese, cobalt, copper, zinc, molybdenum, selenium, iodine, bromine, fluorine. They affect the metabolism. Their absence is the cause of diseases (zinc - diabetes mellitus, iodine - endemic goiter, iron - pernicious anemia, etc.).

Modern medicine knows the facts of the negative interaction of vitamins and minerals:

Zinc reduces the absorption of copper and competes for absorption with iron and calcium; (and zinc deficiency causes weakening immune system, a number of pathological conditions on the part of the endocrine glands).

Calcium and iron reduce the absorption of manganese;

Vitamin E is poorly combined with iron, and vitamin C with B vitamins.

Positive mutual influence:

Vitamin E and selenium, as well as calcium and vitamin K, act synergistically;

Vitamin D is required for the absorption of calcium;

Copper aids in the absorption and utilization of iron in the body.

Inorganic components of the cell.

Water- the most important component cells, a universal dispersion medium of living matter. The active cells of terrestrial organisms are 60 - 95% water. In resting cells and tissues (seeds, spores) water is 10 - 20%. Water in the cell is in two forms - free and bound to cellular colloids. Free water is a solvent and dispersion medium of the protoplasmic colloidal system. Its 95%. Bound water(4 - 5%) of all cell water forms fragile hydrogen and hydroxyl bonds with proteins.

Water properties:

Water is a natural solvent for mineral ions and other substances.

Water is the dispersed phase of the colloidal system of protoplasm.

Water is a medium for the reactions of cell metabolism, because physiological processes occur in an exclusively aquatic environment. Provides reactions of hydrolysis, hydration, swelling.

Participates in many enzymatic reactions of the cell and is formed in the process of metabolism.

Water is a source of hydrogen ions during photosynthesis in plants.

Biological significance of water:

Most biochemical reactions take place only in aqueous solution, many substances enter and leave cells in a dissolved form. This characterizes the transport function of water.

Water provides hydrolysis reactions - the breakdown of proteins, fats, carbohydrates under the action of water.

Thanks to the high heat of evaporation, the body is cooled. For example, perspiration in humans or transpiration in plants.

The high heat capacity and thermal conductivity of water contributes to an even distribution of heat in the cell.

Due to the forces of adhesion (water - soil) and cohesion (water - water), water has the property of capillarity.

The incompressibility of water determines the stressed state of the cell walls (turgor), the hydrostatic skeleton in roundworms.

More, others - less.

At the atomic level, there are no differences between the organic and inorganic world of living nature: living organisms consist of the same atoms as bodies of inanimate nature. However, the ratio of different chemical elements in living organisms and in the earth's crust is very different. In addition, living organisms may differ from their environment in terms of the isotopic composition of chemical elements.

All elements of the cell can be conventionally divided into three groups.

Macronutrients

Zinc- part of the enzymes involved in alcoholic fermentation, the composition of insulin

Copper- is a part of oxidative enzymes involved in the synthesis of cytochromes.

Selenium- participates in the regulatory processes of the body.

Ultramicroelements

Ultramicroelements make up less than 0.0000001% in the organisms of living beings, they include gold, silver has a bactericidal effect, inhibits the reabsorption of water in the renal tubules, affecting enzymes. Platinum and cesium are also referred to as ultramicroelements. Some also include selenium in this group, with a lack of it, cancers develop. The functions of ultramicroelements are still poorly understood.

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