Basic chemical elements of cells table. Cell composition

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

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

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

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

The blood of mammals contains 24 trace elements, and the human brain contains 18 trace elements.

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 the molecular level. Thus, along with inorganic substances (water and mineral salts), the cells of living organisms contain substances 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, i.e. from macroelements. Microelements are contained in these substances in small quantities, however, their role in the normal functioning of organisms is enormous. For example, compounds of boron, manganese, zinc, and cobalt dramatically increase the yield of individual agricultural plants and increase their resistance to various diseases.

Humans and animals receive the microelements they need for normal life through the plants they eat. If there is not enough manganese in food, then growth retardation, delayed puberty, and metabolic disorders during the formation of the skeleton are possible. Adding fractions of a milligram of manganese salts to the daily diet of animals eliminates these diseases.

Cobalt is part of vitamin B12, which is responsible for the functioning of 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 microelements for humans was first revealed during 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 quantities prevents disease. For this purpose, table salt is iodized, to which 0.001-0.01% potassium iodide is added.

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

Many microelements are contained in vitamins - organic substances of various chemical natures that enter the body with food in small doses and have a great impact on metabolism and the overall functioning of the body. In their biological action, they are close to enzymes, but enzymes are formed by the cells of the body, and vitamins usually come 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.

Microelements are also part of hormones - biologically active substances that regulate the functioning of organs and organ systems in humans and animals. They take their name from the Greek word harmao - I conquer. Hormones are produced by the endocrine glands and enter the blood, which carries them throughout the body. Some hormones are obtained synthetically.

1. Macroelements and microelements.

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

3. Organic substances: 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 macroelements also called biogenic? List them.

1. Give definitions of concepts.
Element- a collection of atoms with the same nuclear charge and the number of protons, coinciding with the serial (atomic) number in the periodic table.
Microelement - 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 involved in the life of a cell and forms the basis of biomolecules.
Elemental composition of the cell - percentage of chemical elements in the cell.

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

3. Fill out the table.

ELEMENTAL COMPOSITION OF A CELL

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

5. Fill out the table.

BIOLOGICAL ROLE OF ELEMENTS

6. Study the section “The role of external factors in the formation of the chemical composition of living nature” in § 2.2 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 a lack of microelements?
Iodine deficiency - endemic goiter. A decrease in the synthesis of thyroxine and, as a result, proliferation of thyroid tissue.
Lack of iron – iron deficiency anemia.

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

9. Choose the correct answer.
Test 1.
What chemical elements form most organic substances?
2) C, O, H, N;

Test 2.
Does not apply to macroelements:
4) manganese.

Test 3.
Living organisms need nitrogen because it serves:
1) a constituent component of proteins and nucleic acids; 10. Determine the characteristic by which all of the following elements, except one, are combined into one group. Emphasize this “extra” element.
Oxygen, hydrogen, sulfur, iron, carbon, phosphorus, nitrogen. Contains only DNA. And the rest are all in proteins.

11. Explain the origin and general meaning of the word (term), based on the meaning of the roots that make it up.

12. Select a term and explain how its modern meaning matches 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 took part only in the construction of tissues and organ cells. 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 part of hormones, vitamins, enzymes and other biomolecules.

13. Formulate and write down the main ideas of § 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 participate in the life of the cell, form the basis of biomolecules, are called bioelements.
Macroelements 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. Without them, the body cannot function. Their deficiency leads to death.
For microelements: 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. Their deficiency causes disease. They are part of biologically active compounds and affect metabolism.
There are ultramicroelements: Au Ag Be, etc. The physiological role has not been definitively 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).
If there is a deficiency of an element due to diet, illness or illness may also occur. For example, with a lack of iron - anemia. With a lack of calcium - frequent fractures, hair loss, teeth loss, muscle pain.

About 70 elements of D.I. Mendeleev’s periodic system of elements were found in the cells of different organisms, but only 24 of them have a well-established significance and are constantly found in all types of cells.

The largest share in the elemental composition of the cell is made up of oxygen, carbon, hydrogen and nitrogen. These are the so-called basic or biogenic elements. These elements account for more than 95% of the mass of cells, and their relative content in living matter is much higher than in the earth’s crust. Calcium, phosphorus, sulfur, potassium, chlorine, sodium, magnesium, iodine and iron are also vital. Their content in the cell is calculated in tenths and hundredths of a percent. The listed elements form a group macronutrients.

Other chemical elements: copper, manganese, molybdenum, cobalt, zinc, boron, fluorine, chromium, selenium, aluminum, iodine, iron, silicon - are contained in extremely small quantities (less than 0.01% of cell mass). They belong to the group microelements.

The percentage content of a particular element in the body in no way characterizes the degree of its importance and necessity in the body. For example, many microelements are part of various biologically active substances - enzymes, vitamins (cobalt is part of vitamin B12), hormones (iodine is part of thyroxine); they influence the growth and development of organisms (zinc, manganese, copper), hematopoiesis (iron, copper), cellular respiration processes (copper, zinc), etc. The content and significance of various chemical elements for the life of cells and the body as a whole are given in the table:

Today, many chemical elements of the periodic table have been discovered and isolated in their pure form, and a fifth of them are found in every living organism. They, like bricks, are the main components of organic and inorganic substances.

What chemical elements are included in the composition of the cell, by the biology of what substances one can judge their presence in the body - we will consider all this later in the article.

What is the constancy of chemical composition?

To maintain stability in the body, each cell must maintain the concentration of each of its components at a constant level. This level is determined by species, habitat, and environmental factors.

To answer the question of what chemical elements are included in the composition of a cell, it is necessary to clearly understand that any substance contains any of the components of the periodic table.

Sometimes we are talking about hundredths and thousandths of a percent of the content of a certain element in a cell, but a change in the said number by even a thousandth can already have serious consequences for the body.

Of the 118 chemical elements in a human cell, there must be at least 24. There are no components that would be found in a living organism, but were not part of inanimate objects of nature. This fact confirms the close connection between living and nonliving things in an ecosystem.

The role of various elements that make up the cell

So what chemical elements make up a cell? Their role in the life of the body, it should be noted, directly depends on the frequency of occurrence and their concentration in the cytoplasm. However, despite the different content of elements in a cell, the importance of each of them is equally high. A deficiency of any of them can lead to detrimental effects on the body, disabling the most important biochemical reactions from metabolism.

When listing what chemical elements make up the human cell, we need to mention three main types, which we will consider further:

Basic biogenic elements of the cell

It is not surprising that the elements O, C, H, N are classified as biogenic, because they form all organic and many inorganic substances. It is impossible to imagine proteins, fats, carbohydrates or nucleic acids without these essential components for the body.

The function of these elements determined their high content in the body. Together they account for 98% of the total dry body mass. What else can the activity of these enzymes be manifested in?

1. Oxygen. Its content in the cell is about 62% of the total dry mass. Functions: construction of organic and inorganic substances, participation in the respiratory chain;
2. Carbon. Its content reaches 20%. Main function: included in all ;
3. Hydrogen. Its concentration takes a value of 10%. In addition to the fact that this element is a component of organic matter and water, it also participates in energy transformations;
4. Nitrogen. The amount does not exceed 3-5%. Its main role is the formation of amino acids, nucleic acids, ATP, many vitamins, hemoglobin, hemocyanin, chlorophyll.

These are the chemical elements that make up the cell and form most of the substances necessary for normal life.

Importance of Macronutrients

Macronutrients will also help tell you what chemical elements are included in the cell. From a biology course it becomes clear that, in addition to the main ones, 2% of the dry mass is made up of other components of the periodic table. And macroelements include those whose content is not lower than 0.01%. Their main functions are presented in table form.

We hope that from the above it is not difficult to determine which chemical elements are part of the cell and belong to the macroelements.

Microelements

There are also components of the cell without which the body cannot function normally, but their content is always less than 0.01%. Let's determine which chemical elements are part of the cell and belong to the group of microelements.

Organic and inorganic substances

In addition to those listed, what other chemical elements are included in the composition of the cell? The answers can be found by simply studying the structure of most substances in the body. Among them, molecules of organic and inorganic origin are distinguished, and each of these groups contains a fixed set of elements.

The main classes of organic substances are proteins, nucleic acids, fats and carbohydrates. They are built entirely from basic biogenic elements: the skeleton of the molecule is always formed by carbon, and hydrogen, oxygen and nitrogen are part of the radicals. In animals, the dominant class is proteins, and in plants, polysaccharides.

Inorganic substances are all mineral salts and, of course, water. Among all the inorganics in the cell, the most is H 2 O, in which the remaining substances are dissolved.

All of the above will help you determine what chemical elements are part of the cell, and their functions in the body will no longer be a mystery to you.

86 chemical elements that are part of D.I.’s Periodic Table of Chemical Elements have been discovered in the human body. Mendeleev. These elements are conventionally divided into four groups:

• macroelements - elements that make up the bulk of the cell (approximately 98-99% in terms of dry weight), including carbon (C), hydrogen (H), oxygen (O) and nitrogen (N);
• elements, the content of which in the cell, calculated on a dry weight basis, is about 1.9%. These are potassium (K), sodium (Na), calcium (Ca), magnesium (Mg), sulfur (S), phosphorus (P), chlorine (Cl) and iron (Fe);
• elements whose content in a cell, calculated on a dry weight basis, is less than 0.01% are microelements. These are zinc (Zn), copper (Cu), fluorine (F), iodine (I), cobalt (Co), molybdenum (Mo), etc.
• elements whose content in a cell, calculated on a dry weight basis, is less than 0.00001% - ultramicroelements: gold (Au), uranium (U), radium (Ra), etc.

The role of chemical elements in the cells of living organisms

Each element that makes up a living organism is responsible for performing a specific function (Table 1).

Table 1. The role of chemical elements in the cells of living organisms.

A deficiency of any element can lead to illness and even death of the body, since each element plays a specific role. Macroelements of the first group form the basis of biopolymers - proteins, carbohydrates, nucleic acids, as well as lipids, without which life is impossible. Sulfur is part of some proteins, phosphorus is part of nucleic acids, iron is part of hemoglobin, and magnesium is part of chlorophyll. Calcium plays an important role in metabolism

Some of the chemical elements contained in the cell are part of inorganic substances - mineral salts and water. Mineral salts are found in the cell, as a rule, in the form of cations (K +, Na +, Ca 2+, Mg 2+) and anions (HPO 4 2-, H 2 PO 4 -, CI -, HCO 3 -), the ratio which determines the acidity of the environment, which is important for the life of cells, the slightly alkaline environment of many cells and its pH almost does not change, because a certain ratio of cations and anions is constantly maintained in it.

Water plays an important role in the chemical reactions that occur in the cell in aqueous solutions. It dissolves metabolic products that the body does not need and thereby promotes their removal from the body. The high water content in the cell gives it elasticity. Water facilitates the movement of various substances within a cell or from cell to cell.

Examples of problem solving

EXAMPLE 1

EXAMPLE 2