Chemical elements in the human body. Organic and inorganic substances

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Human body- an open biological system. The human body is a multi-level system. It consists of organ systems, each organ system is made up of organs, each organ is made up of tissues, and tissues are made up of cells. Each cell is a system of interconnected organelles.

The human body is an open system that constantly exchanges substances and energy with the environment. From it, oxygen enters the body during gas exchange, and along with food, water and nutrients. To the outside, the body removes carbon dioxide, undigested food debris, urine, sweat, and secretions from the sebaceous glands.

Externally, the body receives thermal energy and nutrients (proteins, fats, carbohydrates), the molecules of which accumulate chemical energy. It is released during the breakdown of these substances in the body. Part of the chemical energy is spent on the process of its life activity, and the excess in the form of heat is returned to the external environment.

Inorganic substances

Among all inorganic substances, the water content in the human body is the highest. It makes up up to 90% of the mass of an embryo and up to 70% of the body mass of an elderly person. Water is a solvent that provides transport of substances in the body. Substances dissolved in water acquire the ability to interact. Water also participates in heat exchange processes between the body and the environment.

The human body contains many inorganic substances. Some of them are present in the form of molecules, such as calcium compounds in bones, substances in the form of ions. Thus, iron ions are involved in the transport of oxygen in the blood, calcium ions are necessary for muscle contraction, and potassium and sodium ions are necessary for the formation and transmission of nerve impulses.

Organic matter

The molecules of many organic substances are made up of blocks - simple organic molecules. All proteins have this structure. They are formed from amino acid molecules. Typically, a chain of amino acids folds into fibrous or club-like structures. This way the protein molecule becomes more compact and takes up less space in the cell.

Every process that occurs in the body involves dozens or even hundreds of different proteins. The proportion of proteins is more than 50% of the dry mass of cells. Some proteins are the building material of cells, others work during muscle contraction, and others protect the body from infections. Almost all chemical reactions in the body occur with the help of enzymes - protein catalysts.

Complex carbohydrates

Like proteins, complex carbohydrates are formed from block molecules. Thus, the blocks of glycogen are molecules of simple carbohydrates - glucose. Glucose in the body plays the role of a source of energy, and glucose reserves are created in the form of glycogen. In combination with proteins and other organic substances, carbohydrates perform a structural function.

Fats

Fats- organic substances insoluble in water. The fat molecule usually contains molecules of glycerol and fatty acids. Fats form the plasma membranes of cells; they accumulate in the cells of adipose tissue, which performs protective functions in the body. Just like glucose, fats are a source of energy. A fat molecule stores more energy than a glucose molecule, but the cell takes much longer to extract energy from fats than from carbohydrates.

Chemical substances were first classified at the end of the 9th century by the Arab scientist Abu Bakr al-Razi. Based on the origin of the substances, he divided them into three groups. In the first group he assigned a place to mineral substances, in the second to plant substances and in the third to animal substances.

This classification was destined to last for almost a millennium. Only in the 19th century two of those groups were formed - organic and inorganic substances. Chemical substances of both types are built thanks to the ninety elements included in D.I. Mendeleev’s table.

Group of inorganic substances

Among inorganic compounds, simple and complex substances are distinguished. The group of simple substances includes metals, nonmetals and noble gases. Complex substances are represented by oxides, hydroxides, acids and salts. All inorganic substances can be built from any chemical elements.

Group of organic substances

The composition of all organic compounds necessarily includes carbon and hydrogen (this is their fundamental difference from mineral substances). Substances formed by C and H are called hydrocarbons - the simplest organic compounds. Hydrocarbon derivatives contain nitrogen and oxygen. They, in turn, are classified into oxygen- and nitrogen-containing compounds.

The group of oxygen-containing substances is represented by alcohols and ethers, aldehydes and ketones, carboxylic acids, fats, waxes and carbohydrates. Nitrogen-containing compounds include amines, amino acids, nitro compounds and proteins. For heterocyclic substances, the position is twofold - they, depending on their structure, can belong to both types of hydrocarbons.

Cell chemicals

The existence of cells is possible if they contain organic and inorganic substances. They die when they lack water and mineral salts. Cells die if they are severely depleted of nucleic acids, fats, carbohydrates and proteins.

They are capable of normal life if they contain several thousand compounds of organic and inorganic nature, capable of entering into many different chemical reactions. The biochemical processes occurring in the cell are the basis of its vital activity, normal development and functioning.

Chemical elements that saturate the cell

Cells of living systems contain groups of chemical elements. They are enriched with macro-, micro- and ultra-microelements.

Macroelements are primarily represented by carbon, hydrogen, oxygen and nitrogen. These inorganic substances of the cell form almost all of its organic compounds. They also include vital elements. A cell is not able to live and develop without calcium, phosphorus, sulfur, potassium, chlorine, sodium, magnesium and iron.
The group of microelements is formed by zinc, chromium, cobalt and copper.
Ultramicroelements are another group representing the most important inorganic substances of the cell. The group is formed by gold and silver, which have a bactericidal effect, and mercury, which prevents the reabsorption of water that fills the kidney tubules and affects enzymes. It also includes platinum and cesium. Selenium plays a certain role in it, the deficiency of which leads to various types of cancer.

Water in the cell

The importance of water, a common substance on earth for cell life, is undeniable. Many organic and inorganic substances dissolve in it. Water is a fertile environment where an incredible number of chemical reactions take place. It is capable of dissolving decay and metabolic products. Thanks to it, waste and toxins leave the cell.

This liquid has high thermal conductivity. This allows heat to spread evenly throughout the body tissues. It has a significant heat capacity (the ability to absorb heat when its own temperature changes minimally). This ability prevents sudden temperature changes from occurring in the cell.

Water has exceptionally high surface tension. Thanks to it, dissolved inorganic substances, like organic ones, easily move through tissues. Many small organisms, using the property of surface tension, stay on the water surface and slide freely along it.

Turgor of plant cells depends on water. In certain species of animals, it is water that copes with the support function, and not any other inorganic substances. Biology has identified and studied animals with hydrostatic skeletons. These include representatives of echinoderms, round and annelids, jellyfish and sea anemones.

Saturation of cells with water

Working cells are filled with water by 80% of their total volume. The liquid exists in them in free and bound form. Protein molecules bind tightly to bound water. They, surrounded by a water shell, are isolated from each other.

Water molecules are polar. They form hydrogen bonds. Thanks to hydrogen bridges, water has high thermal conductivity. Bound water allows cells to withstand cold temperatures. Free water accounts for 95%. It promotes the dissolution of substances involved in cellular metabolism.

Highly active cells in brain tissue contain up to 85% water. Muscle cells are 70% saturated with water. Less active cells that form adipose tissue need 40% water. It not only dissolves inorganic chemicals in living cells, it is a key participant in the hydrolysis of organic compounds. Under its influence, organic substances, breaking down, turn into intermediate and final substances.

The importance of mineral salts for the cell

Mineral salts are represented in cells by cations of potassium, sodium, calcium, magnesium and anions HPO 4 2-, H 2 PO 4 -, Cl -, HCO 3 -. The correct proportions of anions and cations create the acidity necessary for cell life. Many cells maintain a slightly alkaline environment, which remains virtually unchanged and ensures their stable functioning.

The concentration of cations and anions in cells is different from their ratio in the intercellular space. The reason for this is active regulation aimed at transporting chemical compounds. This course of processes determines the constancy of chemical compositions in living cells. After cell death, the concentration of chemical compounds in the intercellular space and cytoplasm reaches equilibrium.

Inorganic substances in the chemical organization of the cell

The chemical composition of living cells does not contain any special elements that are unique to them. This determines the unity of the chemical compositions of living and nonliving objects. Inorganic substances in the composition of the cell play a huge role.

Sulfur and nitrogen help proteins form. Phosphorus is involved in the synthesis of DNA and RNA. Magnesium is an important component of enzymes and chlorophyll molecules. Copper is necessary for oxidative enzymes. Iron is the center of the hemoglobin molecule, zinc is part of the hormones produced by the pancreas.

Importance of inorganic compounds for cells

Nitrogen compounds convert proteins, amino acids, DNA, RNA and ATP. In plant cells, ammonium ions and nitrates are converted into NH 2 during redox reactions and become involved in the synthesis of amino acids. Living organisms use amino acids to form their own proteins needed to build their bodies. After the death of organisms, proteins are poured into the cycle of substances; during their decay, nitrogen is released in free form.

Inorganic substances that contain potassium play the role of a “pump”. Thanks to the “potassium pump,” substances that they urgently need penetrate into the cells through the membrane. Potassium compounds lead to the activation of cell activity, thanks to which excitations and impulses are carried out. The concentration of potassium ions in cells is very high, in contrast to the environment. After the death of living organisms, potassium ions easily pass into the natural environment.

Substances containing phosphorus contribute to the formation of membrane structures and tissues. In their presence, enzymes and nucleic acids are formed. Various layers of soil are saturated to varying degrees with phosphorus salts. Root secretions of plants, dissolving phosphates, absorb them. Following the death of organisms, the remaining phosphates undergo mineralization, turning into salts.

Inorganic substances containing calcium contribute to the formation of intercellular substance and crystals in plant cells. Calcium from them penetrates into the blood, regulating the process of blood clotting. Thanks to it, bones, shells, calcareous skeletons, and coral polyps are formed in living organisms. Cells contain calcium ions and crystals of its salts.

Inorganic substances in the human body

Minerals play an important role in the human body. Minerals actively participate in all biochemical and intercellular processes occurring within us.

The periodic table of elements (Mendeleev's table) currently contains almost 120 chemical elements. More than 80 elements have been found in the human body. Of these, a person needs about 20 macro- and microelements for normal life.

Essential elements. Vital (essential) microelements have an effect on the human body indirectly, controlling the vital activity of hormones, enzymes, proteins, fats, carbohydrates, vitamins and other biologically active substances. This management occurs by maintaining their certain ratio and concentration in the body.

Macronutrients:

A) Organogenic elements

H, O, C, N - 98%

+S,P- bioelements form organic compounds.

b) K, Na, Ca, Mg, Fe, Cl- about 2%

P, Ca– formation of bone tissue, bone strength.

Sa. After 4 main elements it ranks fifth. In an adult, up to 700 mg of calcium is removed from bone tissue per day and the same amount is deposited again. Consequently, bone tissue, in addition to its supporting function, plays the role of a depot of calcium and phosphorus, from where the body extracts them when there is a lack of dietary intake.

Ca- ensures blood clotting.

K, Na, Cl– permeability of cell membranes, conduction of nerve impulses.

Fe- is part of hemoglobin.

Mg- is part of chlorophyll in plants and enzymes in animals.

Microelements– content about 0.02%

Zn is part of insulin - a hormone of the pancreas, enhances the activity of the gonads.

Cu ensures tissue growth and is part of enzymes.

I is part of thyroxine, a thyroid hormone.

Zn is part of insulin, a pancreatic hormone.

F is part of the enamel of teeth.

Co part of vitamin B 12 (cobalamin)

Mn ensures metabolism.

B responsible for the growth process.

Mo responsible for the use of iron and the retention of fluoride in the body.

Flaw macro- and microelements leads to various diseases. And to prevent them, you need to eat certain foods. A deficiency or excess in the body of any of these elements entails serious changes in its functioning and can often lead to serious complications. Therefore, for the normal functioning of the body, a certain balance of minerals must be maintained.

The most common shortages in Ukraine are iodine, zinc, selenium, magnesium, manganese and copper. In addition, in women during pregnancy and in children during periods of strong growth, there is often a deficiency in the body gland.

If there is a shortage calcium Osteoporosis develops (softness, porosity of bones), slowdown in skeletal growth. It is necessary to consume dairy products.
If there is a shortage magnesium muscle cramps, loss of body fluids. Products: vegetables, beans, nuts, milk, fruits.
If there is a shortage chlorine- dry skin. Ingredients: water, table salt.
If there is a shortage sodium– headache, poor memory, loss of appetite. Products: tomatoes, apricots, peas, table salt.
If there is a shortage potassium– arrhythmia of heart contractions, sudden death with increasing loads. Products – bananas, dried fruits, potatoes, tomatoes, zucchini.
Phosphorus– external signs of deficiency are unknown. Contained in fish, dairy products, walnuts, buckwheat.
If there is a shortage gland anemia develops. It is necessary to eat liver, meat, green leaves of vegetables.
If there is a shortage fluorine a – tooth decay. Products - fish, water.
If there is a shortage zinc– skin damage. Products – meat, seafood.
If there is a shortage iodine goiter develops. It is necessary to eat persimmons, seafood, and iodized salt.
If there is a shortage copper– cancer, liver dysfunction. Products – liver, egg yolk, whole grains.
With a lack of cobalt, pernicious anemia develops. Products - liver, animal proteins.

In addition to water, among the inorganic substances that make up the cell, salts, which are ionic compounds, should be mentioned. In an aqueous solution, they dissociate to form a metal cation and an acid residue anion.
Cells are most important for life processes
Cations: K, Na, Ca, Mg.
Anions: H2PO4, Cl, HCO3.
The concentration of ions on the outer surface of the cell is different from their concentration on the inner surface. The outer surface of the cell membrane has a very high concentration of sodium ions, and the inner surface has a high concentration of potassium ions. As a result, a potential difference is formed between the inner and outer surfaces of the cell membrane, which causes the transmission of excitation along a nerve or muscle.
Calcium and magnesium ions are activators of many enzymes.
Its buffering properties depend on the concentration of salts inside the cell.
Buffering is the ability of a cell to maintain a slightly alkaline reaction at a constant level. Buffering inside the cell is provided by anions H 2 P.O. 4 And NRO 4 .
In extracellular fluid and blood they play the role of a buffer N 2 CO 3 And NSO 3 .
Anions of weak acids and weak alkalis bind hydrogen ions and hydroxide ions, due to which the reaction inside the cell does not change.
Hydrochloric acid creates an acidic environment in the stomach, speeding up the digestion of food proteins.
Calcium and phosphorus ions are found in bone tissue.
Mineral salts enter the body's cells from the external environment. Excess salts along with water are excreted from the body into the external environment.