The cell contains about 70 elements of Mendeleev's Periodic Table of Elements, and 24 of them are present in all types of cells. All elements present in the cell are divided, depending on their content in the cell, into groups:

• macronutrients– H, O, N, C,. Mg, Na, Ca, Fe, K, P, Cl, S;
• microelements– B, Ni, Cu, Co, Zn, Mb, etc.;
• ultramicroelements– U, Ra, Au, Pb, Hg, Se, etc.

• organogens(oxygen, hydrogen, carbon, nitrogen),
• macroelements,
• microelements.

Molecules that make up a cell inorganic And organic connections.

Inorganic compounds of the cell – water And inorganic ions.
Water- the most important inorganic substance of the cell. All biochemical reactions occur in aqueous solutions. The water molecule has a nonlinear spatial structure and has polarity. Hydrogen bonds are formed between individual water molecules, which determine the physical and chemical properties water.

Physical properties of water	Implications for biological processes
High heat capacity (due to hydrogen bonds between molecules) and thermal conductivity (due to small molecular sizes)	Transpiration Sweating Periodic precipitation
Transparency in the visible spectrum	Highly productive biocenoses of ponds, lakes, rivers (due to the possibility of photosynthesis at shallow depths)
Almost complete incompressibility (due to intermolecular cohesion forces)	Maintaining the shape of organisms: the shape of the succulent organs of plants, the position of grasses in space, the hydrostatic skeleton of roundworms, jellyfish, amniotic fluid supports and protects the fetus of mammals
Molecular mobility (due to weak hydrogen bonds)	Osmosis: the flow of water from the soil; plasmolysis
Viscosity (hydrogen bonds)	Lubricating properties: synovial fluid in joints, pleural fluid
Solvent (molecular polarity)	Blood, tissue fluid, lymph, gastric juice, saliva, in animals; cell sap in plants; aquatic organisms use oxygen dissolved in water
The ability to form a hydration shell around macromolecules (due to the polarity of the molecules)	Dispersion medium in the colloidal system of the cytoplasm
Optimal for biological systems the value of surface tension forces (due to intermolecular cohesion forces)	Aqueous solutions are a means of transporting substances in the body
Expansion upon freezing (due to the formation of a maximum number of 4 hydrogen bonds by each molecule)	Ice is lighter than water and acts as a heat insulator in reservoirs.

Inorganic ions:
cations K+, Na+, Ca2+, Mg2+ and anions Cl–, NO3-, PO4 2-, CO32-, HPO42-.

The difference between the number of cations and anions (Nа + , TO + , Cl-) on the surface and inside the cell ensures the occurrence of an action potential, which underlies nervous and muscle stimulation.
Phosphoric acid anions create phosphate buffer system , maintaining the pH of the intracellular environment of the body at a level of 6-9.
Carbonic acid and its anions create bicarbonate buffer system and maintain the pH of the extracellular environment (blood plasma) at a level of 7-4.
Nitrogen compounds serve source mineral nutrition, protein synthesis, nucleic acids.
Phosphorus atoms are part of nucleic acids, phospholipids, as well as the bones of vertebrates and the chitinous cover of arthropods.
Calcium ions are part of the substance of bones; they are also necessary for muscle contraction and blood clotting.

Table. The role of macroelements at the cellular and organismal level of organization.

Table.

Thematic assignments

Part A

A1. The polarity of water determines its ability
1) conduct heat
3) dissolve sodium chloride
2) absorb heat
4) dissolve glycerin

A2. Children with rickets should be given medications containing
1) iron
2) potassium
3) calcium
4) zinc

A3. The conduction of a nerve impulse is provided by ions:
1) potassium and sodium
2) phosphorus and nitrogen
3) iron and copper
4) oxygen and chlorine

A4. Weak bonds between water molecules in its liquid phase are called:
1) covalent
2) hydrophobic
3) hydrogen
4) hydrophilic

A5. Hemoglobin contains
1) phosphorus
2) iron
3) sulfur
4) magnesium

A6. Select group chemical elements, which is necessarily part of proteins
1) Na, K, O, S
2) N, P, C, Cl
3) C, S, Fe, O
4) C, H, O, N

A7. For patients with hypofunction thyroid gland give medications containing
1) iodine
2) iron
3) phosphorus
4) sodium

Part B

B1. Select the functions of water in the cage
1) energy
2) enzymatic
3) transport
4) construction
5) lubricating
6) thermoregulatory

B2. Select only physical properties water
1) ability to dissociate
2) hydrolysis of salts
3) density
4) thermal conductivity
5) electrical conductivity
6) electron donation

Part C

C1. What physical properties of water determine it biological significance?

A cell is the elementary structural unit of living organisms. All living things - be they humans, animals, plants, fungi or bacteria - have a cell at their core. In someone's body there are many of these cells - hundreds of thousands of cells make up the body of mammals and reptiles, but in someone's body there are few - many bacteria consist of just one cell. But the number of cells is not as important as their presence.

It has long been known that cells have all the properties of living things: they breathe, feed, reproduce, adapt to new conditions, and even die. And, like all living things, cells contain organic and inorganic substances.

Much more, because it is also water, and of course, the largest part of the section called “inorganic substances of the cell” is allocated to water - it makes up 40-98% of the total volume of the cell.

Water in a cell performs many important functions: it ensures the elasticity of the cell and the speed of processes passing through it. chemical reactions, the movement of incoming substances throughout the cell and their removal. In addition, many substances dissolve in water, it can participate in chemical reactions, and it is water that is responsible for the thermoregulation of the entire body, since water has good thermal conductivity.

In addition to water, the inorganic substances of the cell also include many mineral substances, divided into macroelements and microelements.

Macroelements include substances such as iron, nitrogen, potassium, magnesium, sodium, sulfur, carbon, phosphorus, calcium and many others.

Trace elements are mostly heavy metals such as boron, manganese, bromine, copper, molybdenum, iodine and zinc.

The body also contains ultramicroelements, including gold, uranium, mercury, radium, selenium and others.

All inorganic substances of the cell play their own role, important role. Thus, nitrogen is involved in a great variety of compounds - both protein and non-protein, and contributes to the formation of vitamins, amino acids, and pigments.

Calcium is a potassium antagonist and serves as a glue for plant cells.

Iron is involved in the respiration process and is part of hemoglobin molecules.

Copper is responsible for the formation of blood cells, heart health and good appetite.

Boron is responsible for the growth process, especially in plants.

Potassium ensures the colloidal properties of the cytoplasm, the formation of proteins and normal heart function.

Sodium also provides correct rhythm cardiac activity.

Sulfur is involved in the formation of some amino acids.

Phosphorus is involved in education huge amount essential compounds, such as nucleotides, some enzymes, AMP, ATP, ADP.

And only the role of ultramicroelements is still completely unknown.

But the inorganic substances of the cell alone could not make it complete and alive. Organic matter is just as important.

C include carbohydrates, lipids, enzymes, pigments, vitamins and hormones.

Carbohydrates are divided into monosaccharides, disaccharides, polysaccharides and oligosaccharides. Mono-di- and polysaccharides are the main source of energy for the cell and the body, but oligosaccharides, which are insoluble in water, glue connective tissue and protect cells from adverse external influences.

Lipids are divided into fats themselves and lipoids - fat-like substances that form oriented molecular layers.

Enzymes are catalysts that accelerate biochemical processes in the body. In addition, enzymes reduce the amount of energy consumed to make a molecule reactivity.

Vitamins are necessary to regulate the oxidation of amino acids and carbohydrates, as well as for full growth and development.

Hormones are necessary to regulate the functioning of the body.

Textbook for grades 10-11

Section I. Cell - a unit of living things
Chapter I. Chemical composition of the cell

Contains in living organisms large number chemical elements. They form two classes of compounds - organic and inorganic. Chemical compounds whose structure is based on carbon atoms make up hallmark alive. These compounds are called organic. Organic compounds are extremely diverse, but only four classes of them have universal biological significance: proteins, nucleic acids, carbohydrates and lipids.

§ 1. Inorganic compounds

Biologically important chemical elements. Of the more than 100 chemical elements known to us, about 80 are included in living organisms, and only 24 are known what functions they perform in the cell. The set of these elements is not accidental. Life originated in the waters of the World Ocean, and living organisms consist primarily of those elements that form compounds that are easily soluble in water. Most of these elements are light; their peculiarity is the ability to form strong (covalent) bonds and form many different complex molecules.

As part of cells human body Oxygen (more than 60%), carbon (about 20%) and hydrogen (about 10%) predominate. Nitrogen, calcium, phosphorus, chlorine, potassium, sulfur, sodium, magnesium taken together account for about 5%. The remaining 13 elements make up no more than 0.1%. The cells of most animals have a similar elemental composition; Only the cells of plants and microorganisms differ. Even those elements that are contained in cells in negligible quantities cannot be replaced by anything and are absolutely necessary for life. Thus, the iodine content in cells does not exceed 0.01%. However, if there is a lack of it in the soil (because of this and in food products) the growth and development of children is delayed. The copper content in animal cells does not exceed 0.0002%. But with a lack of copper in the soil (hence in plants), massive diseases of farm animals occur.

The meaning for the basic element cell is given at the end of this paragraph.

Inorganic (mineral) compounds. The composition of living cells includes a number of relatively simple compounds that are also found in inanimate nature - in minerals, natural waters. These are inorganic compounds.

Water is one of the most abundant substances on Earth. It covers most of earth's surface. Almost all living things are composed primarily of water. In humans, the water content in organs and tissues varies from 20% (in bone tissue) up to 85% (in the brain). About 2/3 of a person’s mass is water, in the body of a jellyfish up to 95% is water, even in dry plant seeds, water is 10-12%.

Water has some unique properties. These properties are so important for living organisms that it is impossible to imagine life without this compound of hydrogen and oxygen.

The unique properties of water are determined by the structure of its molecules. In a water molecule, one oxygen atom is covalently bonded to two hydrogen atoms (Fig. 1). The water molecule is polar (dipole). Positive charges are concentrated on hydrogen atoms, since oxygen is more electronegative than hydrogen.

Rice. 1. Formation of hydrogen bonds in water

The negatively charged oxygen atom of one water molecule is attracted to the positively charged hydrogen atom of another molecule to form a hydrogen bond (Figure 1).

The strength of a hydrogen bond is approximately 15-20 times weaker than a covalent bond. Therefore, the hydrogen bond is easily broken, which is observed, for example, during the evaporation of water. Due to the thermal movement of molecules in water, some hydrogen bonds are broken and others are formed.

Thus, in liquid water the molecules are mobile, which is important for metabolic processes. Water molecules easily penetrate cell membranes.

Due to the high polarity of its molecules, water is a solvent for other polar compounds. More substances dissolve in water than in any other liquid. That is why in aquatic environment cells carry out many chemical reactions. Water dissolves metabolic products and removes them from the cell and the body as a whole.

Water has a high heat capacity, i.e. the ability to absorb heat with a minimal change in its own temperature. Thanks to this, it protects the cell from sudden changes in temperature. Since a lot of heat is consumed to evaporate water, by evaporating water, organisms can protect themselves from overheating (for example, when sweating).

Water has high thermal conductivity. This property creates the possibility of uniform distribution of heat between body tissues.

Water serves as a solvent for “lubricants”, which are needed wherever there are rubbing surfaces (for example, in joints).

Water has its maximum density at 4°C. Therefore, ice, which has a lower density, is lighter than water and floats on its surface, which protects the reservoir from freezing.

In relation to water, all cell substances are divided into two groups: hydrophilic - “loving water” and hydrophobic - “afraid of water” (from the Greek “hydro” - water, “phileo” - love and “phobos” - fear).

Hydrophilic substances include substances that are highly soluble in water. These are salts, sugars, amino acids. Hydrophobic substances, on the contrary, are practically insoluble in water. These include, for example, fats.

Cell surfaces that separate the cell from external environment, and some other structures consist of water-insoluble (hydrophobic) compounds. Thanks to this, the structural integrity of the cell is maintained. A cell can be figuratively represented as a vessel with water, where biochemical reactions take place that ensure life. The walls of this vessel are insoluble in water. However, they are capable of selectively permeating water-soluble compounds.

In addition to water, this does not include organic matter cells should be called salts, which are ionic compounds. They are formed by cations of potassium, sodium, magnesium and other metals and anions of hydrochloric, carbonic, sulfuric, and phosphoric acids. When such salts dissociate, cations (K +, Na +, Ca 2+, Mg 2+, etc.) and anions (CI -, HCO 3 -, HS0 4 -, etc.) appear in solutions. The concentration of ions on the outer surface of the cell differs from their concentration on inner surface. Different number potassium and sodium ions on the inner and outer surfaces of the cell creates a charge difference on the membrane. On the outer surface of the cell membrane there is very high concentration sodium ions, and on the inner surface there is a very high concentration of potassium ions and a low concentration of sodium. As a result, a potential difference is formed between the internal and outer surface cell membrane, which causes the transmission of excitation along a nerve or muscle.

Calcium and magnesium ions are activators of many enzymes, and if they are deficient, vital functions are impaired. important processes in cells. Row important functions performed in living organisms inorganic acids and their salts. Hydrochloric acid creates an acidic environment in the stomach of animals and humans and in special bodies insectivorous plants, accelerating the digestion of food proteins. Phosphoric acid residues (H 3 P0 4), joining a number of enzymatic and other cell proteins, change their physiological activity. Residues of sulfuric acid, joining foreign substances insoluble in water, impart solubility to them and thus contribute to their removal from cells and organisms. Sodium and potassium salts nitrous and phosphoric acids, calcium salt of sulfuric acid are important components mineral nutrition of plants, they are applied to the soil as fertilizers to feed plants. The meaning of chemical elements for a cell is given in more detail below.

Biologically important chemical elements of the cell

1. What is biological role water in the cage?
2. What ions are contained in the cell? What is their biological role?
3. What role do the cations contained in the cell play?

All organisms on our planet consist of cells that are similar in chemical composition. In this article we will briefly talk about the chemical composition of the cell, its role in the life of the entire organism, and find out what science studies this issue.

Groups of elements of the chemical composition of the cell

The science that studies the components and structure of a living cell is called cytology.

All elements included in chemical structure organism can be divided into three groups:

• macroelements;
• microelements;
• ultramicroelements.

Macroelements include hydrogen, carbon, oxygen and nitrogen. They account for almost 98% of all constituent elements.

Microelements are present in tenths and hundredths of a percent. And a very low content of ultramicroelements - hundredths and thousandths of a percent.

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Translated from Greek, “macro” means big, and “micro” means small.

Scientists have found that there are no special elements that are unique to living organisms. Therefore, both living and inanimate nature consists of the same elements. This proves their relationship.

Despite the quantitative content of a chemical element, the absence or reduction of at least one of them leads to the death of the entire organism. After all, each of them has its own meaning.

The role of the chemical composition of the cell

Macroelements are the basis of biopolymers, namely proteins, carbohydrates, nucleic acids and lipids.

Microelements are part of vital organic substances and participate in metabolic processes. They are constituent components of mineral salts, which are in the form of cations and anions, their ratio determines the alkaline environment. Most often it is slightly alkaline, because the ratio of mineral salts does not change.

Hemoglobin contains iron, chlorophyll - magnesium, proteins - sulfur, nucleic acids - phosphorus, metabolism occurs when sufficient quantity calcium.

Rice. 2. Cell composition

Some chemical elements are components of inorganic substances, such as water. She's playing big role in the life activity of both plants and animal cell. Water is a good solvent, because of this all substances inside the body are divided into:

• Hydrophilic - dissolves in water;
• Hydrophobic - do not dissolve in water.

Thanks to the presence of water, the cell becomes elastic, it promotes the movement of organic substances in the cytoplasm.

Rice. 3. Cell substances.

Table “Properties of the chemical composition of the cell”

To clearly understand what chemical elements are part of the cell, we included them in the following table:

Elements		Meaning
Macronutrients
Oxygen, carbon, hydrogen, nitrogen
		A constituent component of the shell in plants, in the animal body it is found in bones and teeth, and takes an active part in blood clotting.
		Contained in nucleic acids, enzymes, bone tissue and tooth enamel.
Microelements
		It is the basis of proteins, enzymes and vitamins.
		Provides transmission nerve impulses, activates protein synthesis, photosynthesis and growth processes.
		One of the components gastric juice, enzyme provocateur.
		Takes an active part in metabolic processes, a component of the thyroid hormone.
		Provides transmission of impulses to nervous system, maintains constant pressure inside the cell, provokes the synthesis of hormones.
		A constituent element of chlorophyll, bone tissue and teeth, provokes DNA synthesis and heat transfer processes.
		An integral part of hemoglobin, the lens, and the cornea, it synthesizes chlorophyll. Transports oxygen throughout the body.
Ultramicroelements
		An integral part of the processes of blood formation and photosynthesis, it accelerates intracellular oxidation processes.
Manganese		Activates photosynthesis, participates in blood formation, and ensures high productivity.
		Component of tooth enamel.
		Regulates plant growth.

What have we learned?

Each cell of living nature has its own set of chemical elements. By their composition, objects are living and inanimate nature have similarities, this proves their close relationship. Each cell consists of macroelements, microelements and ultramicroelements, each of which has its own role. The absence of at least one of them leads to illness and even death of the entire organism.

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A cell is not only a structural unit of all living things, a kind of building block of life, but also a small biochemical factory in which various transformations and reactions occur every fraction of a second. This is how the necessary components for the life and growth of the body are formed. structural components: cell minerals, water and organic compounds. Therefore, it is very important to know what will happen if one of them is not enough. What role do various compounds play in the life of these tiny structural particles of living systems, invisible to the naked eye? Let's try to understand this issue.

Classification of cell substances

All compounds that make up the mass of the cell, form its structural parts and are responsible for its development, nutrition, respiration, plastic and normal development, can be divided into three large groups. These are categories such as:

• organic;
• cells (mineral salts);
• water.

Often the latter is classified as the second group of inorganic components. In addition to these categories, we can identify those that are made up of their combination. These are the metals that make up the molecule organic compounds(for example, the hemoglobin molecule containing iron ion is protein in nature).

Cell minerals

If we talk specifically about the mineral or inorganic compounds that make up each living organism, then they are also different in nature and in quantitative content. Therefore, they have their own classification.

All inorganic compounds can be divided into three groups.

1. Macroelements. Those whose content inside the cell is more than 0.02% of the total mass of inorganic substances. Examples: carbon, oxygen, hydrogen, nitrogen, magnesium, calcium, potassium, chlorine, sulfur, phosphorus, sodium.
2. Microelements - less than 0.02%. These include: zinc, copper, chromium, selenium, cobalt, manganese, fluorine, nickel, vanadium, iodine, germanium.
3. Ultramicroelements - content less than 0.0000001%. Examples: gold, cesium, platinum, silver, mercury and some others.

You can also especially highlight several elements that are organogenic, that is, they form the basis of organic compounds from which the body of a living organism is built. These are elements such as:

• hydrogen;
• nitrogen;
• carbon;
• oxygen.

They build molecules of proteins (the basis of life), carbohydrates, lipids and other substances. However, minerals are also responsible for the normal functioning of the body. Chemical composition A cell contains dozens of elements from the periodic table, which are the key to successful life. Only about 12 of all atoms do not play a role at all, or it is negligible and not studied.

Some salts are especially important, which must be supplied to the body with food every day in sufficient quantities so as not to develop various diseases. For plants, this is, for example, sodium; for humans and animals, this is calcium salts, table salt as a source of sodium and chlorine, etc.

Water

Minerals cells combine with water to general group therefore, it is impossible not to talk about its significance. What role does it play in the body of living beings? Huge. At the beginning of the article, we compared a cell to a biochemical factory. So, all the transformations of substances that occur every second are carried out in the aquatic environment. It is a universal solvent and medium for chemical interactions, synthesis and decomposition processes.

In addition, water is part of the internal environment:

• cytoplasm;
• cell sap in plants;
• blood in animals and humans;
• urine;
• saliva and other biological fluids.

Dehydration means death for all organisms without exception. Water is a living environment for a huge number of diverse representatives of flora and fauna. Therefore, it is difficult to overestimate the importance of this inorganic substance; it is truly infinitely great.

Macronutrients and their importance

Cell minerals for her normal operation have great value. First of all, this applies to macroelements. The role of each of them has been studied in detail and has long been established. We have already listed which atoms make up the group of macroelements above, so we will not repeat ourselves. Let us briefly outline the role of the main ones.

1. Calcium. Its salts are necessary for the supply of Ca 2+ ions to the body. The ions themselves are involved in the processes of stopping and coagulating blood, providing cell exocytosis, as well as muscle contractions, including cardiac ones. Insoluble salts - basis strong bones and animal and human teeth.
2. Potassium and sodium. They maintain the condition of the cell and form a sodium-potassium pump for the heart.
3. Chlorine - participates in ensuring the electrical neutrality of the cell.
4. Phosphorus, sulfur, nitrogen are components of many organic compounds, and also take part in muscle function and bone composition.

Of course, if we consider each element in more detail, then a lot can be said about both its excess in the body and its deficiency. After all, both are harmful and lead to various kinds of diseases.

Microelements

The role of minerals in the cell, which belong to the group of microelements, is also great. Despite the fact that their content is very small in the cell, without them it will not be able to function normally for a long time. The most important of all the atoms listed above in this category are:

• zinc;
• copper;
• selenium;
• fluorine;
• cobalt.

Normal iodine levels are necessary to maintain thyroid function and hormone production. The body needs fluoride to strengthen tooth enamel, and plants need it to maintain the elasticity and rich color of leaves.

Zinc and copper are elements found in many enzymes and vitamins. They are performing important participants processes of synthesis and plastic exchange.

Selenium is an active participant in regulatory processes and is necessary for work endocrine system element. Cobalt has another name - vitamin B 12, and all compounds in this group are extremely important for the immune system.

Therefore, the functions of mineral substances in the cell, which are formed by microelements, are no less than those performed by macrostructures. Therefore, it is important to consume both in sufficient quantities.

Ultramicroelements

The mineral substances of the cell, which are formed by ultramicroelements, do not play as significant a role as the above. However, their long-term deficiency can lead to the development of very unpleasant and sometimes very dangerous consequences for health.

For example, selenium also belongs to this group. Its long-term lack provokes the development cancerous tumors. Therefore, it is considered indispensable. But gold and silver are metals that have a negative effect on bacteria, destroying them. Therefore, inside the cells they play a bactericidal role.

However, in general, it should be said that the functions of ultramicroelements have not yet been fully revealed by scientists, and their significance remains unclear.

Metals and organics

Many metals are found in organic molecules. For example, magnesium is a coenzyme of chlorophyll, necessary for plant photosynthesis. Iron is part of the hemoglobin molecule, without which it is impossible to breathe. Copper, zinc, manganese and others are parts of the molecules of enzymes, vitamins and hormones.

Obviously, all these compounds are important for the body. It is impossible to classify them completely as mineral, but they still partially should.

Cell minerals and their significance: grade 5, table

To summarize what we said during the article, let’s make general table, in which we will reflect what mineral compounds there are and why they are needed. It can be used when explaining this topic to schoolchildren, for example, in the fifth grade.

Thus, the mineral substances of the cell and their significance will be learned by schoolchildren in the course of the main stage of education.

Consequences of a lack of mineral compounds

When we say that the role of minerals in the cell is important, we must give examples that prove this fact.

Let us list some diseases that develop with a deficiency or excess of any of the compounds identified during the article.

1. Hypertension.
2. Ischemia, heart failure.
3. Goiter and other thyroid diseases ( Graves' disease and others).
4. Anemia.
5. Improper growth and development.
6. Cancerous tumors.
7. Fluorosis and caries.
8. Blood diseases.
9. Disorder of the muscular and nervous system.
10. Indigestion.

Of course, this is far from full list. Therefore, it is necessary to carefully ensure that daily diet nutrition was correct and balanced.