Basic functions of minerals. Chemical composition of the cell

Goals:

Educational:

• Systematization of knowledge about the chemical composition of the cell.
• Consolidating knowledge about chemical elements and their role in the cells of living organisms, the chemical community of living and inanimate nature.
• Understanding the role of chemicals for the normal functioning of the human body.

Educational:

• the formation of a worldview, an active life position, experience of correct behavior and communication, the transformation of these valuable properties into stable moral qualities of the individual, the formation of readiness for self-education and mental development; develop students' subject competence. Instill hygienic skills for a healthy lifestyle.

Educational:

• development of intelligence, attention, perception, memory, thinking, imagination, speech, emotional-volitional sphere of schoolchildren; highlighting the most important, dominant tasks of the lesson, their specification taking into account the characteristics and capabilities of the team.

Equipment: diagram “Chemical elements”, pictures of plants and animals, signs of chemical elements, flour, tripod, glass rod, porcelain cup.

Tasks:

1. Talk about the unity of the chemical composition of living organisms and inanimate nature.
2. Reveal the role of minerals in the life of a cell of a living organism.

Lesson plan:

1. Testing knowledge on the topic “Methods of Cytology”, “Cell Theory” (story, tests).
2. New topic:
   1. Chemical composition of the cell.
   2. Classification of minerals (according to content in the cell).
   3. The role of macro and microelements in the life of a cell.
   4. The role of chemical elements in the human body.
3. Consolidation.
4. Homework.

Lesson progress

I. Test of knowledge:

1. Methods and tasks of cytology.

2. Magnifying devices. The device of a light microscope. How to find out the total magnification of a light microscope?

3. History of the formation of cytology. The contribution of individual scientists to the development of cell theory.

4. Test cards:

Cell division was discovered and established that each cell comes from the original one by division:
a) Leeuwenhoek
b) R. Hooke
c) R. Brown
d) R. Vikhrov

The cellular structure of organisms of all kingdoms indicates:
a) the unity of the organic world
b) the similarity between living and inanimate nature
c) the origin of living things from non-living things
d) similarity in the structure of bacteria, viruses, fungi.

The creators of the cell theory are:
a) Darwin and Wallace
b) Mendel and Morgan
c) Hooke and Leeuwenhoek
d) Schleiden and Schwann

The cell theory corresponds to the following statement:
A) cell reproduction occurs through cell division
B) chromosomes – material carriers of heredity
C) all living beings, except bacteria, have a cellular structure.
D) the cells of all living beings and viruses are similar in structure and function

What is the commonality between the conclusions of the cellular and atomic-molecular theories?
A) in establishing the unit of structure of the object
b) in the similarity of the structure of the objects of study
c) in the similarity of properties of the objects of study

II. New topic: And now we will look at the demonstration experience.

Demonstration experiment “Burning flour in a porcelain cup”

What substances are formed when flour burns? What signs of reaction did you observe?

Signs of a reaction:

• water droplets (water vapor condenses on a cold glass plate);
• smoke (organic substances burn);
• ash (inorganic substances). (Slide)

So, living organisms include organic and inorganic substances, as well as water. Today in the lesson we will focus on the study of inorganic substances in the cells of living organisms, we will find out what role certain chemical elements play in the life processes of living organisms.

Listen, guys, to the lines from S. Shchipachev’s poem “Reading Mendeleev”:

There is nothing else in nature
Neither here nor there, in the depths of space:
Everything – from small grains of sand to planets –
It consists of uniform elements.

Guys, in biology and chemistry lessons we were more than once convinced that we are surrounded by a world of chemical compounds. In any living organism, including the human body, many chemical reactions continuously occur. We can say that every living cell is a microscopic chemical laboratory. The entry of chemicals occurs as a result of an important property of the cell - metabolism and energy.

Guys, let's remember and answer the following questions:

• What is metabolism?
• What is the importance of metabolism?
• What are the main directions of metabolism?
• What is assimilation?
• What is dissimilation?

Each type of organism is characterized by a special, genetically fixed type of metabolism. Any disease is accompanied by metabolic disorders, and genetically determined metabolic disorders are the cause of many hereditary diseases.

Many chemists know the famous words spoken in the 40s of this century by the German scientists Walter and Ida Noddack, that every cobblestone on the pavement contains all the elements of the Periodic Table. At first, these words were not met with unanimous approval. However, as more and more accurate methods for the analytical determination of chemical elements were developed, scientists became increasingly convinced of the truth of these words.

If we agree that every cobblestone contains all the elements, then this should also be true for a living organism. All living organisms on Earth, including humans, are in close contact with the environment. Life requires constant metabolism in the body. The entry of chemical elements into the body is facilitated by nutrition and consumed water.

Teacher: How many chemical elements does the modern periodic table include? D.I. Mendeleev?

Of the 118 elements existing in nature, more than 13 have no significance for the functioning of living organisms, but 90 elements, to a greater or lesser extent, take part in the construction of a living organism and in the processes occurring in it. The main building materials are four elements: carbon, hydrogen, oxygen and nitrogen, and the rest, often found in very microscopic quantities in the body, affect health, and a deficiency or excess of any element is often the cause of a particular disease.

There are no special elements characteristic only of living organisms, and this is one of the proofs of the commonality of living and inanimate nature. But the quantitative content of certain elements in living organisms and in the inanimate environment surrounding them differs significantly. For example, silicon in soil is about 33%, and in terrestrial plants only 0.15%. Such differences indicate the ability of living organisms to accumulate only those elements that they need for life.

To study the quantitative composition of chemical elements contained in the cells of living organisms, we will carry out independent work using a textbook. Independent work of students (5 minutes).

• Write down the chemical elements that together make up 98% of the total contents of the cell.
• Write down the chemical elements whose content in the cell is calculated in tenths and hundredths of a percent.

Teacher: Guys, let's check the completion of independent work.

So, we have identified three groups of elements: macroelements - the share of which is 98% and microelements - the share of which is 1.9%, ultramicroelements, their concentration does not exceed 10-5%. These include uranium, radium, gold, silver, beryllium, selenium and other rare elements.

Many chemical elements that make up a cell perform a specific function. Chemical elements that are part of the cell and perform biological functions are called biogenic. Biogenic elements include about 30 elements. Among the biogenic elements, a special place is occupied by the so-called elements - organogens, which form the most important substances in living organisms - water, proteins, fats, carbohydrates, vitamins, hormones, etc. Organogens include six elements - C, O, H, N, H, S.

Biogenic elements also include a number of metals, among which ten, the so-called “metals of life,” perform particularly important biological functions. These metals are four s - elements C, K, Na, Mg and six d elements - Fe, Zn, Cu, Mn, Mo, Co.

Macroelements include oxygen (65-75%), carbon (15-18%), hydrogen (8-10%), nitrogen (2.0-3.0%), potassium (0.15-0.4%) , sulfur (0.15-0.2%), phosphorus (0.2-1.0%), chlorine (0.05-0.1%), magnesium (0.02-0.03%), sodium (0.02-0.03%), calcium (0.04-2.00%), iron (0.01-0.015%. Elements such as C, O, H, N, S, P are included in organic compounds.

And now we will listen to students’ presentations about the role of macroelements in the cell and in the body of plants, animals and humans. During the speech of our comrades, we fill out the table in our notebooks. (Slide)

1. Oxygen is part of almost all organic substances of the cell. It is formed during photosynthesis during photolysis of water. For aerobic organisms, it serves as an oxidizing agent during cellular respiration, providing cells with energy. It is found in the largest quantities in living cells in water. Not only is it an essential part of the air and drinking water we breathe, it also occupies a significant place in our body. With 65% of our total body weight, oxygen is the most important chemical element in the composition of the human body.
2. Carbon - is part of all organic substances; a skeleton of carbon atoms forms their basis. In addition, in the form of CO2 it is fixed during photosynthesis and released during respiration, in the form of CO (in low concentrations) it participates in the regulation of cellular functions, and in the form of CaCO3 it is part of mineral skeletons.
3. Hydrogen, like oxygen, is a component of air and drinking water. And it also refers to the basic components of the human body. 10% of our weight is made up of hydrogen. Hydrogen is part of all organic substances in the cell. It is found in the largest quantities in water. Some bacteria oxidize molecular hydrogen to produce energy.
4. Nitrogen is part of proteins, nucleic acids and their monomers - amino acids and nucleotides. It is excreted from the body of animals as ammonia, urea, guanine or uric acid as the final product of nitrogen metabolism. In the form of nitric oxide, NO (in low concentrations) is involved in the regulation of blood pressure. Although nitrogen is also found in the air, it is better known as a coolant in liquid form. However, its mysteriously evaporating gases should not be misleading - 3% of our body mass consists of nitrogen.
5. Could sulfur, with its unpleasant appearance and smell, be important for our body? Yes, that's exactly it. Sulfur is an essential component of amino acids and coenzymes. Sulfur is part of sulfur-containing amino acids and is therefore found in most proteins. It is present in small quantities as sulfate ion in the cytoplasm of cells and intercellular fluids.
6. Phosphorus, as a luminous substance, is known to everyone. But not everyone knows that it is thanks to phosphorus in the body that DNA, the basis of human life, is formed. Phosphorus is part of ATP, other nucleotides and nucleic acids (in the form of phosphoric acid residues), in bone tissue and tooth enamel (in the form of mineral salts), and is also present in the cytoplasm and intercellular fluids (in the form of phosphate ions).
7. Magnesium is vital for all organisms on earth, naturally, for us people too. Despite its insignificant part - 0.05% of our body weight, a lack of magnesium leads to clearly noticeable consequences: Nervousness, headaches, fatigue and muscle cramps are just some of them. Magnesium is a cofactor for many enzymes involved in energy metabolism and DNA synthesis; maintains the integrity of ribosomes and mitochondria, is part of chlorophyll. In animal cells it is necessary for the functioning of muscle and bone systems.
8. Even if it is only 1.5%, calcium is an important metal in our body. It is what gives strength to our bones and teeth. Calcium - is involved in blood coagulation, and also serves as one of the universal second messengers, regulating the most important intracellular processes (including participation in maintaining membrane potential, necessary for muscle contraction and exocytosis). Insoluble calcium salts are involved in the formation of bones and teeth of vertebrates and mineral skeletons of invertebrates.
9. We consume sodium primarily in the form of sodium chloride, also known as table salt. The element is important for the protection of cells and the movement of nerve signals. Sodium - is involved in maintaining membrane potential, generating nerve impulses, osmoregulation processes (including kidney function in humans) and creating a blood buffer system.
10. Potassium, at a modest 0.2%, plays a small role in body processes. It belongs to the electrolytes that our body needs primarily during sports. Its deficiency can cause feelings of exhaustion and cramps. Potassium - is involved in maintaining membrane potential, generating nerve impulses, and regulating cardiac muscle contraction. Contained in intercellular substances.

Teacher: The vital elements sodium and potassium function in pairs. It has been reliably established that all living organisms are characterized by the phenomenon of ion asymmetry - the uneven distribution of ions inside and outside the cell. For example, inside the cells of muscle fibers, heart, liver, and kidneys there is an increased content of potassium ions compared to the extracellular content. The concentration of sodium ions, on the contrary, is higher outside the cell than inside it. The presence of a concentration gradient of potassium and sodium is an experimentally established fact. Interestingly, as the body ages, the concentration gradient of potassium and sodium ions at the cell boundary decreases. When death occurs, the concentrations of potassium and sodium inside and outside the cell immediately equalize. The human body contains on average about 140 g of potassium and about 100 g of sodium. With food, we consume daily from 1.5 to 7 g of potassium ions and from 2 to 15 g of sodium ions. The need for Na ions is so great that they must be specially added to food (in the form of table salt). A significant loss of sodium ions (they are excreted from the body in urine and sweat) has an adverse effect on human health. Therefore, in hot weather, doctors recommend eating more salty foods. However, their excess content in food causes a negative reaction of the body, for example, an increase in blood pressure.

Teacher: The content of elements in the body is explained by the following quatrains.

Our blood tastes a little salty -
It contains sodium chloride;
In the intercellular space sodium-plus
Osmosis pressure for cells will be maintained.
Chloride ions reign in the stomach,
To supply hydrochloric acid
To provide us - this is not a joke -
Protein foods break down the tails.

Composition of the human body.

The French chemist G. Bertrand calculated that the body of a person weighing about 100 kg contains oxygen 63 kg, carbon - 19 kg, hydrogen - 9 kg, nitrogen - 5 kg, calcium - 1 kg, phosphorus - 700 g, sulfur - 640 g , sodium - 25o g, potassium - 220 g, chromium - 180 g, magnesium - 80 g, iron - 3 g, iodine - 0.03 g. Fluorine, bromine, manganese, copper - even less. Do the math

Now we will look at microelements Slide Microelements, which make up from 0.001% to 0.000001% of the body weight of living beings, include vanadium, germanium, iodine, cobalt, manganese, nickel, ruthenium, selenium, fluorine, copper, chromium, zinc.

Among all microelements, the so-called essential microelements are classified into a special group. Essential microelements are microelements, the regular intake of which with food or water into the body is absolutely necessary for its normal functioning. Essential microelements are part of enzymes, vitamins, hormones and other biologically active substances. Essential microelements are: iron, iodine, copper, manganese, zinc, cobalt, molybdenum, selenium, chromium, fluorine.

Questions for the class:

• What diseases are caused by a lack of chemical elements in plant and animal organisms?
• What foods contain microelements?
• What is the biological role of microelements?

You are invited to listen carefully to the messages prepared by your classmates and answer the questions asked above.

1. “Biological role of fluorine”

Fluorine is found in living organisms in small quantities. The human body contains about 2.6 g of fluoride, of which 2.5 g is in the bones. The biological role of fluorine is that it participates in the formation of teeth and bones, in metabolism and in the activation of certain enzymes. The normal intake of fluoride into the human body is from 2.5 to 3.5 mg per day. A decrease or increase in the amount of fluoride causes various diseases. Chronic poisoning with fluoride compounds causes the disease fluorosis.

Teacher: And I want to add a funny poem to what has been said

Research has proven
What is fluorine as a trace element?
So important for tooth enamel,
As for construction cement.
Known: for fluoride deficiency
Toothache occurs soon.
Excess fluoride is also bad:
You can be left without teeth.

2. “Biological role of cobalt”

Cobalt is a trace element that has a diverse effect on the life processes of plant, animal and human organisms. The human body contains 0.03 g of cobalt, of which 14% is found in bones, 43% each in muscles and soft tissues. Most cobalt is found in the liver, kidneys and pancreas. The biological role of cobalt is great - it participates in hematopoietic metabolic processes, affects protein, fat, carbohydrate, mineral metabolism, and vitamin metabolism. For example, vitamin C accelerates the synthesis of vitamin PP and is part of enzymes (peptidase).

Cobalt is a component of vitamin B12.

3. “Biological role of copper”

Copper is one of the most important microelements involved in photosynthesis processes and affects the absorption of nitrogen by plants. The human body contains about 0.1 g of copper. The daily requirement of an adult is from 2 to 3 mg. Copper is concentrated in the liver, blood, brain, and bones. Copper deficiency and excess are equally harmful to the body. With a lack of copper in the human diet, the formation of hemoglobin decreases and anemia develops, bone formation is impaired with changes in the skeleton. Excess copper accumulates in the liver, brain, kidneys, eyes and causes chronic inflammatory processes in tissues.

Teacher: Thanks guys for your performances.

It turns out that it is possible to create an elemental portrait of any person that strictly corresponds to gender, age, constitution, temperament and, of course, lifestyle. The elemental “portrait” is the chemical composition, i.e. the content of macro- and microelements that we “carry” within ourselves. And if any changes occur in our life (organism), then they affect our elemental composition, which reacts very quickly to any collisions.

An accurate diagnosis of stress, which is often the cause of the disease, can, it turns out, be established by the spectral composition of hair. The concentration of all chemical elements that exist in our body is much higher in hair than in such biological fluids as are usual for analysis, such as blood and urine. In addition, hair concentrates almost all the chemical elements found in our body. For example, if it is possible to reliably obtain data on 6–8 elements from blood serum, then hair “gives out” information about 20–30 elements. All analyzes are carried out using a plasma spectrometer. The results of the analysis are processed on a computer, which extracts from its memory information about the average norm of macro- and microelements for a healthy person of a given gender and age, compares the elemental composition of the patient’s hair with them and evaluates deviations in the mineral composition. First of all, the content of such vital elements as calcium, potassium, iron, copper, magnesium, zinc is determined, because their functions are extremely important for our body.

Based on the noted imbalance, a preliminary diagnosis is made, then a treatment program is determined aimed at eliminating the deficiency of the missing element and removing harmful or excess substances from the body. This correction of the body’s mineral metabolism can be carried out by drawing up a special diet including foods that contain significant quantities of elements necessary for the normal functioning of your body (and the diet should be prepared only by specialists)

In the hair of a person who thinks a lot, it was determined that there is more zinc and copper in comparison with others. Manganese, lead, titanium, copper and silver are predominant in those with dark hair color. Gray hair contains only nickel. Moreover, they are associated with wisdom.

Gold is also found in hair. Moreover, in terms of its content, women are truly more precious than men. Although Genghis Khan allegedly had a whole tuft of golden hair on the back of his head.

Ultramicroelements make up less than 0.0000001% in the organisms of living beings, these include gold, silver have a bactericidal effect, mercury suppresses the reabsorption of water in the renal tubules, affecting enzymes. Platinum and cesium are also considered ultramicroelements. Some people also include selenium in this group; with its deficiency, cancer develops. Selenium is one of the essential microelements. At the same time, in case of an overdose, it is highly toxic, so its use as a dietary supplement causes great debate in scientific circles.

The functions of ultramicroelements are still poorly understood.

• So guys, what new did you learn in class?
• What did you like?
• What didn't you like?
• What surprised you?

Grading.

1). They play the role of cofactors in enzymatic reactions. Thus, many ions form complexes with proteins, including enzymes. For the full manifestation of their catalytic activity, the latter require the presence of mineral cofactors - potassium, calcium, sodium, magnesium, and iron ions. Iron, copper and especially magnesium ions are necessary for the activation of enzymes associated with the transfer and release of energy, transport and oxygen binding.

2). They take part in maintaining osmotic pressure and acid-base balance (phosphate and bicarbonate buffers).

3). Provides blood clotting processes

4). Create membrane potential and action potential of excitable cells

5). Minerals are included in the structures of various organs of the body. Inorganic substances can be in the form of insoluble compounds in the body (for example, in bone and cartilage tissue).

6). Participate in redox reactions, etc.

Sodium and potassium ions play a major role in mineral metabolism. These cations determine the pH value, osmotic pressure, and volume of body fluids. They participate in the formation of bioelectric potentials and in the transport of amino acids, sugars and ions across the cell membrane. Sodium makes up 93% of all blood plasma cations; its concentration in blood plasma is 135-145 mmol/l. Potassium is mainly an intracellular cation; in blood plasma its concentration is 3.3-4.9 mmol/l.

The body of a healthy person weighing about 70 kg contains 150-170 g of sodium. Of these, 25-30% are part of the bones and do not directly participate in metabolism. About 70% of the total sodium in the body is actually exchangeable sodium.

The daily diet of residents of civilized countries contains on average 10-12 g of sodium chloride, but the true human need for it is much lower and approaches 4-7 g. This amount of sodium chloride is contained in ordinary food, which casts doubt on the need for additional salting.

Excessive intake of table salt can lead to an increase in the volume of body fluids, increasing the load on the heart and kidneys. Under these conditions, the increase in the penetration of sodium, and with it water, into the intercellular spaces of the tissues of the walls of blood vessels contributes to their swelling and thickening, as well as the narrowing of the lumen of blood vessels.

The constancy of the content of sodium and potassium ions in the blood plasma is maintained mainly by the kidneys. With a decrease in sodium concentration and an increase in potassium, sodium reabsorption increases and potassium reabsorption decreases, and potassium secretion in the renal tubules increases under the influence of the adrenal cortex mineralocorticoid aldosterone.

The body of a healthy person weighing 70 kg contains 45-35 mmol/kg of potassium. Of these, only 50-60 mmol are in the extracellular space, and the rest of the potassium is concentrated in the cells. Thus, potassium is the main intracellular cation. With age, the total potassium content in the body decreases.

Daily potassium intake is 60-100 mmol; Almost the same amount is excreted by the kidneys and only a little (2%) is excreted in the feces.

The physiological role of potassium is its participation in all types of metabolism, in the synthesis of ATP, and therefore it affects contractility. Its deficiency causes atony of skeletal muscles, a moderate excess causes an increase in tone, and a very high content paralyzes the muscle fiber. Potassium causes vasodilation. It is also involved in the synthesis of acetylcholine, in the destruction of cholinesterase and, therefore, affects the synaptic transmission of excitation. Together with other ions, it provides the cell with the ability to excite.

Chlorine is the second extracellular anion after sodium. Its concentration in extracellular fluid and plasma is 103-110 mmol/l. The total chlorine content in the body is about 30 mmol/kg. A significant amount of chlorine was found only in the cells of the gastric mucosa. It is this that is the reserve for the synthesis of hydrochloric acid in gastric juice, combining with hydrogen ions, which are extracted from the blood by the cells of the mucous membrane and removed into the lumen of the stomach.

Normal plasma calcium levels are 2.1-2.6 mmol/l. Of these, 50% are associated with plasma proteins (especially albumin), 10% are part of soluble complexes, 40% are in free ionized form, which is of greatest interest from a clinical point of view.

Only free Ca 2+ ions are physiologically active, therefore the regulation of metabolism is aimed at maintaining a constant plasma concentration not of total calcium, but only of its physiologically active fraction.

Calcium ions bound to phosphorus ions have the greatest functional activity. Calcium takes an active part in the processes of excitation, synaptic transmission, muscle contraction, cardiac activity, participates in the oxidative phosphorylation of carbohydrates and fats, in blood clotting, affects the permeability of cell membranes, and forms the structural basis of the bone skeleton. A significant portion of intracellular calcium is located in the endoplasmic reticulum (T tanks).

The main role in regulating the balance between plasma calcium and bone calcium belongs to the hormone of the parathyroid glands (parathyrin).

When food containing significant amounts of calcium is consumed, most of it is excreted through the intestines as a result of precipitation in the main intestinal environment in the form of insoluble compounds.

Phosphorus enters the body mainly with dairy, meat, fish and legume products. Its concentration in blood serum is 0.81-1.45 mmol/l. The daily requirement for phosphorus is approximately 1.2 g, in pregnant and lactating women - up to 1.6-1.8 g. Phosphorus is an anion of intracellular fluid, high-energy compounds, coenzymes of tissue respiration and glycolysis. Insoluble calcium phosphates constitute the major mineral component of bones, giving them strength and hardness. Salts of phosphoric acid and its esters are components of buffer systems for maintaining the acid-base state of tissues.

Iron is necessary for oxygen transport and for oxidative reactions, as it is part of hemoglobin and mitochondrial cytochromes. Its concentration in the blood in combination with the transport protein transferrin is normally 1.0-1.5 mg/l. The daily requirement for iron for men is 10 mg; for women of childbearing age, due to menstrual blood loss, this value is much higher and approaches 18 mg. For pregnant and lactating women, due to the needs of the child’s body, this parameter approaches 33 and 38 mg, respectively. Iron is found in meat, liver, legumes, buckwheat and millet cereals. Insufficient iron intake in the body is common. Thus, 10-30% of women of childbearing age have iron deficiency anemia.

Iodine is the only known trace element involved in the construction of hormone molecules. Sources of iodine are sea plants and sea fish, meat and dairy products. The iodine concentration in blood plasma is 10-15 mcg/l. The daily requirement is 100-150 mcg, for pregnant and lactating women - 180-200 mcg. Up to 90% of organic iodine circulating in the blood comes from thyroxine and triiodothyronine. Insufficient intake of iodine in the body can cause dysfunction of the thyroid gland.

Fluoride protects teeth from caries. The daily need for fluoride is 0.5-1.0 mg. It enters the body with drinking water, fish, nuts, liver, meat, and oat products. It is believed that it blocks microelements necessary for the activation of bacterial enzymes. Fluoride stimulates hematopoiesis, immune reactions, and prevents the development of senile osteoporosis.

Magnesium is an intracellular cation (Mg 2+), contained in the body in an amount of 30 mmol/kg body weight. The concentration of magnesium in blood plasma is 0.65-1.10 mmol/l. The daily requirement for it is about 0.4 g. Magnesium is a catalyst for many intracellular processes, especially those related to carbohydrate metabolism. It reduces the excitability of the nervous system and the contractile activity of skeletal muscles, helps to dilate blood vessels, reduce heart rate and lower blood pressure.

The cell consists of organic and mineral substances.

Mineral composition of cells

Of the inorganic substances, the cell composition includes 86 elements of the Periodic Table, about 16-18 elements are vital for the normal existence of a living cell.

Among the elements there are: organogens, macroelements, microelements and ultramicroelements.

Organogens

These are the substances that make up organic matter: oxygen, carbon, hydrogen and nitrogen.

Oxygen(65-75%) - found in a huge number of organic molecules - proteins, fats, carbohydrates, nucleic acids. In the form of a simple substance (O2), it is formed during oxygenic photosynthesis (cyanobacteria, algae, plants).

Functions: 1. Oxygen is a strong oxidizing agent (oxidizes glucose during cellular respiration, energy is released in the process)

2. Part of the organic substances of the cell

3. Part of the water molecule

Carbon(15-18%) - is the basis of the structure of all organic substances. Carbon dioxide is released during respiration and absorbed during photosynthesis. It can be in the form of CO - carbon monoxide. In the form of calcium carbonate (CaCO3) it is part of bones.

Hydrogen(8 - 10%) - like carbon, it is part of any organic compound. It is also part of the water.

Nitrogen(2 - 3%) - is part of amino acids, and therefore proteins, nucleic acids, some vitamins and pigments. Fixed by bacteria from the atmosphere.

Macronutrients

Magnesium (0,02 - 0,03%)

1. In the cell - part of enzymes, involved in DNA synthesis and energy metabolism

2. In plants - part of chlorophyll

3. In animals - part of the enzymes involved in the functioning of muscle, nervous and bone tissues.

Sodium (0,02 - 0,03%)

1. In the cell - part of potassium-sodium channels and pumps

2. In plants - participates in osmosis, which ensures the absorption of water from the soil

3. In animals - participates in kidney function, maintaining heart rhythm, is part of the blood (NaCl), helps maintain acid-base balance

Calcium (0,04 - 2,0%)

1. In the cell - participates in the selective permeability of the membrane, in the process of connecting DNA with proteins

2. In plants - forms salts of pectin substances, imparts hardness to the intercellular substance connecting plant cells, and also participates in the formation of intercellular contacts

3. In animals - is part of the bones of vertebrates, shells of mollusks and coral polyps, participates in the formation of bile, increases the reflex excitability of the spinal cord and the center of salivation, participates in the synaptic transmission of nerve impulses, in the processes of blood coagulation, is a necessary factor in the reduction of striated muscles

Iron (0,02%)

1. In the cell - part of cytochromes

2. In plants - participates in the synthesis of chlorophyll, is part of enzymes involved in respiration, is part of cytochromes

3. In animals - part of hemoglobin

Potassium (0,15 - 0,4%)

1. In the cell - maintains the colloidal properties of the cytoplasm, is part of potassium-sodium pumps and channels, activates enzymes involved in protein synthesis during glycolysis

2. In plants - participates in the regulation of water metabolism and photosynthesis

3. Necessary for proper heart rhythm, participates in the conduction of nerve impulses

Sulfur (0,15 - 0,2%)

1. In the cell - it is part of some amino acids - citine, cysteine ​​and methionine, forms disulfide bridges in the tertiary structure of protein, is part of some enzymes and coenzyme A, is part of bacteriochlorophyll, some chemosynthetics use sulfur compounds to produce energy

2. In animals - part of insulin, vitamin B1, biotin

Phosphorus (0,2 - 1,0%)

1. In the cell - in the form of phosphoric acid residues it is part of DNA, RNA, ATP, nucleotides, coenzymes NAD, NADP, FAD, phosphorylated sugars, phospholipids and many enzymes; it forms membranes as part of phospholipids

2. In animals - part of bones, teeth, in mammals it is a component of the buffer system, maintains the acid balance of tissue fluid relatively constant

Chlorine (0,05 - 0,1%)

1. In the cell - participates in maintaining the electroneutrality of the cell

2. In plants - participates in the regulation of turgor pressure

3. In animals - participates in the formation of the osmotic potential of blood plasma, as well as in the processes of excitation and inhibition in nerve cells, is part of the gastric juice in the form of hydrochloric acid

Microelements

Copper

1. In the cell - part of the enzymes involved in the synthesis of cytochromes

2. In plants - part of the enzymes involved in the reactions of the dark phase of photosynthesis

3. In animals - participates in the synthesis of hemoglobin, in invertebrates it is part of hemocyanins - oxygen carriers, in humans - it is part of the skin pigment - melanin

Zinc

1. Participates in alcoholic fermentation

2. In plants - part of the enzymes involved in the breakdown of carbonic acid and in the synthesis of plant hormones-auxins

Iodine

1. In vertebrates - part of the thyroid hormones (thyroxine)

Cobalt

1. In animals - part of vitamin B12 (takes part in the synthesis of hemoglobin), its deficiency leads to anemia

Fluorine

1. In animals - gives strength to bones and tooth enamel

Manganese

1. In the cell - part of enzymes involved in respiration, fatty acid oxidation, increases carboxylase activity

2. In plants - as part of enzymes, it participates in dark reactions of photosynthesis and in the reduction of nitrates

3. In animals - part of the phosphatase enzymes necessary for bone growth

Bromine

1. In the cell - part of vitamin B1, which is involved in the breakdown of pyruvic acid

Molybdenum

1. In the cell - as part of enzymes, it participates in the fixation of atmospheric nitrogen

2. In plants - as part of enzymes, it participates in the work of stomata and enzymes involved in the synthesis of amino acids

Bor

1. Affects plant growth

Inorganic ions, or minerals, perform the following functions in the body:

1. Bioelectric function. This function is associated with the occurrence of a potential difference on cell membranes. The ion concentration gradient on both sides of the membrane creates a potential of about 60-80 mV in different cells. The inner side of the cell membrane is negatively charged relative to the outer. The higher the electrical potential of the membrane, the higher the protein content and its ionization (negative charge) inside the cell and the concentration of cations outside the cell (the diffusion of Na + and K + ions through the membrane into the cell is difficult). This function of inorganic ions is used to regulate the functions of especially excitable cells (nerve, muscle) and to conduct nerve impulses.

2. Osmotic function used to regulate osmotic pressure. A living cell obeys the law of isosmopolarity: in all environments of the body, between which there is a free exchange of water, the same osmotic pressure is established. If the number of ions in a certain medium increases, then water rushes after them until a new equilibrium and a new level of osmotic pressure are established.

3. Structural function due to the complexing properties of metals. Metal ions interact with anionic groups of proteins, nucleic acids and other macromolecules and thereby ensure, along with other factors, the maintenance of certain conformations of these molecules. Since the biological activity of biopolymers depends on their conformations, the normal implementation of their functions by proteins, the unhindered implementation of information contained in nucleic acids, the formation of supramolecular complexes, the formation of subcellular structures and other processes are unthinkable without the participation of cations and anions.

4. Regulatory function is that metal ions are enzyme activators and thereby regulate the rate of chemical transformations in the cell. This is a direct regulatory effect of cations. Indirectly, metal ions are often necessary for the action of another regulator, for example, a hormone. Let's give a few examples. The formation of the active form of insulin is impossible without zinc ions. The tertiary structure of RNA is largely determined by the ionic strength of the solution, and cations such as Cr 2+, Ni 2+, Fe 2+, Zn 2+, Mn 2+ and others are directly involved in the formation of the helical structure of nucleic acids. The concentration of Mg 2+ ions affects the formation of such a supramolecular structure as ribosomes.

5. Transport function manifests itself in the participation of certain metals (as part of metalloproteins) in the transfer of electrons or simple molecules. For example, iron and copper cations are part of cytochromes, which are carriers of electrons in the respiratory chain, and iron in hemoglobin binds oxygen and participates in its transfer.

6. Energy function associated with the use of phosphate anions in the formation of ATP and ADP (ATP is the main carrier of energy in living organisms).

7. Mechanical function. For example, the Ca +2 cation and phosphate anion are part of the hydroxylapatite and calcium phosphate of bones and determine their mechanical strength.

8. Synthetic function. Many inorganic ions are used in the synthesis of complex molecules. For example, iodine ions I¯ are involved in the synthesis of iodothyronines in thyroid cells; anion (SO 4) 2- - in the synthesis of ester-sulfur compounds (during the neutralization of harmful organic alcohols and acids in the body). Selenium is important in the mechanism of protection against the toxic effects of peroxide. It forms selenocysteine, an analogue of cysteine, in which selenium atoms replace sulfur atoms. Selenocysteine ​​is a component of the enzyme glutathione peroxidase, which catalyzes the reduction of hydrogen peroxide with glutathione (tripeptide - γ-glutamyl-cysteinylglycine)

It is important to note that, within certain limits, interchangeability of some ions is possible. If there is a deficiency of a metal ion, it can be replaced by another metal ion that is similar in physicochemical properties and ionic radius. For example, the sodium ion is replaced by a lithium ion; calcium ion - strontium ion; molybdenum ion - vanadium ion; iron ion - cobalt ion; sometimes magnesium ions - manganese ions.

Due to the fact that minerals activate the action of enzymes, they affect all aspects of metabolism. Let us consider how the metabolism of nucleic acids, proteins, carbohydrates and lipids depends on the presence of certain inorganic ions.

A cell is an elementary unit of a living thing, possessing all the characteristics of an organism: the ability to reproduce, grow, exchange substances and energy with the environment, irritability, and the constancy of chemical output.
Macroelements are elements whose amount in a cell is up to 0.001% of body weight. Examples are oxygen, carbon, nitrogen, phosphorus, hydrogen, sulfur, iron, sodium, calcium, etc.
Microelements are elements whose amount in a cell ranges from 0.001% to 0.000001% of body weight. Examples are boron, copper, cobalt, zinc, iodine, etc.
Ultramicroelements are elements whose content in a cell does not exceed 0.000001% of body weight. Examples are gold, mercury, cesium, selenium, etc.

2. Make a diagram of “Cell Substances”.

3. What does the scientific fact of the similarity of the elementary chemical composition of living and inanimate nature indicate?
This indicates the commonality of living and inanimate nature.

Inorganic substances. The role of water and minerals in cell life.
1. Give definitions of concepts.
Inorganic substances are water, mineral salts, acids, anions and cations present in both living and non-living organisms.
Water is one of the most common inorganic substances in nature, the molecule of which consists of two hydrogen atoms and one oxygen atom.

2. Draw a diagram of the “Structure of Water”.

3. What structural features of water molecules give it unique properties, without which life is impossible?
The structure of the water molecule is formed by two hydrogen atoms and one oxygen atom, which form a dipole, that is, water has two polarities “+” and “-”. This contributes to its permeability through the membrane walls, the ability to dissolve chemicals. In addition, water dipoles are connected by hydrogen bonds to each other, which ensures its ability to be in different states of aggregation, as well as to dissolve or not dissolve various substances.

4. Fill out the table “The role of water and minerals in the cell.”

5. What is the significance of the relative constancy of the internal environment of a cell in ensuring its vital processes?
The constancy of the internal environment of the cell is called homeostasis. Violation of homeostasis leads to damage to the cell or to its death, plastic metabolism and energy exchange are constantly occurring in the cell, these are two components of metabolism, and disruption of this process leads to damage or death of the entire organism.

6. What is the purpose of buffer systems of living organisms and what is the principle of their functioning?
Buffer systems maintain a certain pH value (an indicator of acidity) of the environment in biological fluids. The principle of operation is that the pH of the medium depends on the concentration of protons in this medium (H+). The buffer system is capable of absorbing or donating protons depending on their entry into the environment from the outside or, conversely, removal from the environment, while the pH will not change. The presence of buffer systems is necessary in a living organism, since due to changes in environmental conditions, pH can vary greatly, and most enzymes work only at a certain pH value.
Examples of buffer systems:
carbonate-hydrocarbonate (mixture of Na2СО3 and NaHCO3)
phosphate (mixture of K2HPO4 and KH2PO4).

Organic substances. The role of carbohydrates, lipids and proteins in cell life.
1. Give definitions of concepts.
Organic substances are substances that necessarily contain carbon; they are part of living organisms and are formed only with their participation.
Proteins are high molecular weight organic substances consisting of alpha amino acids linked into a chain by a peptide bond.
Lipids are a large group of natural organic compounds, including fats and fat-like substances. The molecules of simple lipids consist of alcohol and fatty acids, complex ones - of alcohol, high-molecular fatty acids and other components.
Carbohydrates are organic substances containing carbonyl and several hydroxyl groups and are otherwise called sugars.

2. Fill in the table with the missing information “Structure and functions of organic substances of the cell.”

3. What is meant by protein denaturation?
Protein denaturation is the loss of a protein's natural structure.

Nucleic acids, ATP and other organic compounds of the cell.
1. Give definitions of concepts.
Nucleic acids are biopolymers consisting of monomers - nucleotides.
ATP is a compound consisting of the nitrogenous base adenine, the carbohydrate ribose and three phosphoric acid residues.
A nucleotide is a nucleic acid monomer that consists of a phosphate group, a five-carbon sugar (pentose) and a nitrogenous base.
A macroergic bond is a bond between phosphoric acid residues in ATP.
Complementarity is the spatial mutual correspondence of nucleotides.

2. Prove that nucleic acids are biopolymers.
Nucleic acids consist of a large number of repeating nucleotides and have a mass of 10,000 to several million carbon units.

3. Describe the structural features of the nucleotide molecule.
A nucleotide is a compound of three components: a phosphoric acid residue, a five-carbon sugar (ribose), and one of the nitrogenous compounds (adenine, guanine, cytosine, thymine or uracil).

4. What is the structure of the DNA molecule?
DNA is a double helix consisting of many nucleotides that are sequentially connected to each other due to covalent bonds between the deoxyribose of one and the phosphoric acid residue of another nucleotide. The nitrogenous bases, which are located on one side of the backbone of one chain, are connected by H-bonds to the nitrogenous bases of the second chain according to the principle of complementarity.

5. Applying the principle of complementarity, construct the second strand of DNA.
T-A-T-C-A-G-A-C-C-T-A-C
A-T-A-G-T-C-T-G-G-A-T-G.

6. What are the main functions of DNA in a cell?
With the help of four types of nucleotides, DNA records all the important information in the cell about the organism, which is passed on to subsequent generations.

7. How does an RNA molecule differ from a DNA molecule?
RNA is a single strand smaller than DNA. Nucleotides contain the sugar ribose, not deoxyribose, as in DNA. The nitrogenous base, instead of thymine, is uracil.

8. What do the structures of DNA and RNA molecules have in common?
Both RNA and DNA are biopolymers made up of nucleotides. What nucleotides have in common in structure is the presence of a phosphoric acid residue and the bases adenine, guanine, and cytosine.

9. Complete the table “Types of RNA and their functions in the cell.”

10. What is ATP? What is its role in the cell?
ATP – adenosine triphosphate, a high-energy compound. Its functions are the universal storer and carrier of energy in the cell.

11. What is the structure of the ATP molecule?
ATP consists of three phosphoric acid residues, ribose and adenine.

12. What are vitamins? What two large groups are they divided into?
Vitamins are biologically active organic compounds that play an important role in metabolic processes. They are divided into water-soluble (C, B1, B2, etc.) and fat-soluble (A, E, etc.).

13. Fill out the table “Vitamins and their role in the human body.”