5 cell minerals and their importance. Minerals and their role in the cell. Brief characteristics of the most important minerals

Test tasks on this topic

"INORGANIC SUBSTANCES OF CELLS"

Choose one correct answer from the given options:

1. Which chemical elements contained in the cell are considered macroelements?
a) Zn, I, F, Br;

c) Ni, Cu, I, Br.

d) Au, Ag, Ra, U.

2. What are the functions of water in a cell?


c) source of energy.

d) transmission of nerve impulses

3. What ions make up hemoglobin?
a) Mg 2+;

4. The transmission of excitation through a nerve or muscle is explained by:

a) the difference in the concentrations of sodium and potassium ions inside and outside the cell

b) breaking of hydrogen bonds between water molecules

c) change in the concentration of hydrogen ions

d) thermal conductivity of water

5 . Of the following substances is hydrophilic:

a) starch

d) cellulose

6. The chlorophyll molecule contains ions

d) Na+
7. At the same time it is part of bone tissue and nucleic acids:

b) phosphorus

c) calcium

8 . Children develop rickets with a deficiency of:

a) manganese and iron

b) calcium and phosphorus

c) copper and zinc

d) sulfur and nitrogen

9 . The composition of gastric juice includes:

10. Most water is contained in cells:
a) embryo;

b) young man;

c) an old man.

d) an adult

11. What chemical elements contained in the cell are classified as microelements?
a) S, Na, Ca, K;

c) Ni, Cu, I, Br.

d) P, S, Cl, Na

12. The composition of gastric juice includes
A) sulfuric acid;

b) hydrochloric acid;

c) carbonic acid.

d) phosphoric acid

13. What are the functions of minerals in a cell?
a) transfer of hereditary information;
b) environment for chemical reactions;
c) source of energy;

d) maintaining the osmotic pressure of the cell.

14. What ions affect blood clotting?
a) Mg 2+;

15 . Iron is included in:

c) hemoglobin

d) chlorophyll

16. Less water is contained in cells:
a) bone tissue;

b) nervous tissue;

c) muscle tissue.

d) adipose tissue

17. Substances that are poorly soluble in water are called:
a) hydrophilic;

b) hydrophobic;

c) amphiphilic.

d) amphoteric

18. Buffering in the cell is provided by ions:
a) Na +, K +;

b) SO 4 2-, Cl -;

c) HCO 3 -, CO 3 2-.

d) Mg 2+; Fe 2+

19. Water is the basis of life, because... she:
a) can be in three states (liquid, solid and gaseous);
b) is a solvent that ensures both the influx of substances into the cell and the removal of metabolic products from it;
c) cools the surface during evaporation.

d) has the property of thermal conductivity

20 . Of the following substances is hydrophobic:

d) potassium permanganate

Sample answers

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. Not organic matter may have 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 cations in the blood plasma, its concentration in the 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. General content chlorine 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 synthesis of hydrochloric acid 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 Active participation 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 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 excitability nervous system and contractile activity of skeletal muscles, helps to dilate blood vessels, reduce heart rate and lower blood pressure.

The human body is very complex. It consists of a huge number of different substances, cells, vitamins. Minerals must be constantly present in the human body, since their role in various processes is great. They take part in the formation of hormones, enzymes, and help a person actively live and function. No organ can do without these substances, since they must be present in a certain amount in almost every cell.

What are minerals?

Many of those who monitor their health are familiar with the statement that vitamins and minerals serve as the basis proper nutrition. Vitamins are almost never synthesized by the body on its own, so they must be supplied with food. At the same time, they are an important biological regulator of many vital processes of the body. Vitamins and minerals are very closely related to each other, since in their chemical composition they can complement each other, sometimes replace each other, providing full life to a person.

Why do the body need them?

Minerals play an important role: they perform a tissue-building function, take part in plastic bioprocesses, and also provide and support many enzymatic reactions human body. But their most important function is to conduct electrochemical impulses in nerve fibers and muscle tissues.

All minerals are divided into macroelements and microelements. Microelements include zinc, iodine, fluorine, manganese, and macroelements include calcium, magnesium, phosphorus, potassium, iron, chlorine. It is not always possible for a person to replenish the supply of minerals in the body through nutrition alone; sometimes it is advisable to use various nutritional supplements and medications. This happens with intense physical activity, the period of vitamin deficiency in the spring, as well as when living conditions do not meet generally accepted standards. In such cases, the mineral substances of the cell decrease in quantity, which sometimes leads to irreversible consequences.

The meaning of calcium, where is it found?

Calcium is an extremely important macronutrient. It ensures normal conductivity of nerve and muscle tissue, acid-base balance, and also performs a construction function for bone and cartilage tissue, which contains up to 98% of all calcium reserves in the human body. Its average daily intake for an adult is 800-1000 mg. To meet calcium needs, you need to consume cottage cheese, milk, eggs, cheese, cauliflower, nuts, sesame and poppy seeds, wheat bran, vegetables and herbs.

Contrary to popular belief, in products with a high content of milk fat (butter, sour cream, cream), the content of this substance is low. Correct absorption of calcium by the body occurs in combination with vitamin D. The most optimal condition for the entry of this element into the body is water and minerals, namely a combination of calcium, magnesium, phosphorus, vitamin C and vitamin D. Experts pay special attention to the calcium content in children’s bodies . After all, this element ensures the growth and development of almost all organs of the growing organism. If the calcium level in children is below normal, serious problems with the musculoskeletal system (rickets) may occur, the growth and health of teeth may be impaired, and a tendency toward pathological processes in the gastrointestinal tract may appear. But a high level of the presence of this microelement in the body is also fraught with health problems, it is especially harmful to the kidneys and liver. Therefore, the balance of this substance in cells and systems is important.

Phosphorus in the body and food

Using phosphorus as an example, it is also easy to assess the importance of minerals for human health. As we noted above, the balance of phosphorus is closely dependent on the balance of calcium. In biological processes, phosphorus is responsible for the formation of enzymes that release and absorb energy from food. In addition, phosphorus maintains proper lipid and energy metabolism, and also stabilizes blood cholesterol levels. The daily intake of phosphorus is 1000-1500 mg. This macronutrient is better absorbed from animal products. To obtain the daily requirement, it is advisable to include fish, fermented milk products, brewer's yeast, pumpkin seeds, oatmeal, nuts, beef liver, eggs, rabbit meat, beets, potatoes, cabbage, carrots, apples, strawberries, currants, watermelon, and pears in your diet. The daily requirement of phosphorus is contained, for example, in 150 grams of hard cheese, 350 grams of oatmeal or 125 grams of pumpkin seeds.

The important role of magnesium, content in products

Magnesium, unlike phosphorus, is better absorbed from plant products. It promotes the proper absorption of phosphorus, calcium, and balances other mineral and organic substances. Magnesium is important for the functioning of the cardiovascular system, as it helps strengthen the walls of blood vessels and has a diuretic effect, which helps stabilize blood pressure.

This trace element is especially important for the functioning of the nervous system. All minerals in the body affect its functioning in one way or another. But processes such as excitability, inhibition, the speed of nerve impulses, their perception by the brain and the reaction to them depend on the amount of magnesium in nerve cells. Magnesium transmits information from the periphery to parts of the central nervous system. Many pregnant women are recommended to take medications containing this substance to improve the functioning of the nervous and cardiovascular systems. For those who experience constant stress at work or at home, physically and mentally exhausted, this element is also useful.

As the mineral table below shows, the daily requirement of magnesium ranges from 300-500 mg. Alcohol, nicotine, fatty foods and caffeine significantly impair the absorption of magnesium. The richest in its content are buckwheat porridge (one serving will provide the body with the daily requirement), bananas, and pumpkin seeds. In addition, magnesium is found in wheat bran, oatmeal, squid and shrimp, dry beans, flounder, spinach, potatoes and white cabbage.

The importance of sodium and potassium for the functioning of the body, from what products can they be obtained?

An important fact is that table salt also contains minerals. You need to consume 10-15 grams of table salt per day to provide the body with a daily supply of sodium (3-6 grams). In the body, this macroelement transports cell minerals and is involved in the regulation of water-salt metabolism. But it is important not to overdo it with the use of this product, since its excessive amount has a detrimental effect on the functioning of some organs and can provoke the accumulation of sand and the formation of stones in the kidneys, gall bladder, and so on.

Potassium is an important element for maintaining healthy heart and blood vessel function. The correct ratio of potassium and calcium allows you to establish the full functioning of the heart muscle. Potassium and sodium are found in bread, legumes, dried apricots, and apples.

Do we contain iron?

Iron is another vital micronutrient. Thanks to it, the body produces the protein hemoglobin, which combines with oxygen and delivers it to the cells, and then removes it carbon dioxide. Thus, the role of minerals, in particular iron, is to supply oxygen to the body. Iron also contributes to proper hematopoietic function. The body of an adult contains 10-30 µmol/liter of iron. A fruit such as quince is very rich in iron; apples, red meat and offal contain a lot of it.

Women need iron more than men, since the fairer sex lives cyclically and loses this microelement in large quantities approximately once a month. To replenish its reserves, you need to consume the above products. Lack of iron in the body leads to anemia.

The importance of chlorine for humans

The importance of chlorine for the body is that it is a component of gastric juice and blood plasma. Together with sodium and potassium, this macronutrient supports water-salt and acid-base metabolism. Up to 90% of the daily value of chlorine enters the body along with regular table salt. If the exchange of chlorine, sodium and potassium is disrupted, the heart function is disrupted, edema appears, and the person suffers from changes in blood pressure.

Is iodine a medicine or an important trace element for the body?

Iodine has been familiar to everyone since childhood due to its antiseptic properties. But it is also a useful trace element. Food rich in iodine must be consumed for proper functioning of the thyroid gland. Iodine is part of the hormones produced by the thyroid gland, and therefore directly affects the proper functioning of the endocrine system. The daily intake of iodine is 100-200 mg. Sea kale and fish are richest in iodine, but modern conditions Life is quite difficult to ensure the balance of iodine in the body. Therefore, it is recommended to take special medications that increase its content.

Fluorine content and receipt by the body

This is a microelement that is part of the enamel of the surface of the teeth, and therefore is responsible for their health and beauty. The body needs 2-3 milligrams of fluoride per day, this need is met through the consumption of various types of tea, seafood and nuts.

What other microelements are important for us?

The table of mineral substances we have compiled contains the main elements and will help you better understand the body’s needs for micro- and macroelements.

In addition to those mentioned above, the list of vital elements includes zinc and manganese. Zinc is a component of enzymes that support the body's redox reactions, and manganese is involved in energy reactions and affects the absorption of many vitamins.

It can be noted that minerals in the diet are very important for your health, as they provide all vital processes. Consuming the correct daily allowance of minerals is the key to health.

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 more content protein and its ionization ( negative charge) inside the cell and the concentration of cations outside the cell (diffusion of Na + and K + ions through the membrane into the cell is difficult). This function inorganic ions are used to regulate the functions of especially excitable cells (nerve, muscle) and to conduct nerve impulses.

2. Osmotic function used to regulate osmotic pressure. 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 speed chemical transformations in a cage. 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. Formation active form 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 syntheses 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 similar in physical and chemical 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.