From this lesson you will learn about the role of mineral compounds of micro- and macroelements in the life of living organisms. You will get acquainted with the hydrogen indicator of the environment - pH, learn how this indicator is related to the physiology of the body, how the body maintains a constant pH of the environment. Find out the role of inorganic anions and cations in metabolic processes, learn details about the functions of Na, K and Ca cations in the body, as well as what other metals are part of our body and what their functions are.
Introduction
Topic: Basics of cytology
Lesson: Minerals and their role in cell life
1. Introduction. Minerals in the cell
Minerals constitute from 1 to 1.5% of the wet weight of the cell, and are found in the cell in the form of salts dislocated into ions, or in the solid state (Fig. 1).
Rice. 1. Chemical composition of cells of living organisms
In the cytoplasm of any cell there are crystalline inclusions, which are represented by slightly soluble calcium and phosphorus salts; In addition to them, there may be silicon oxide and other inorganic compounds that participate in the formation of supporting structures of the cell - in the case of the mineral skeleton of radiolarians - and the body, that is, they form the mineral substance of bone tissue.
2. Inorganic ions: cations and anions
Inorganic ions are important for the life of the cell (Fig. 2).
Rice. 2. Formulas of the main ions of the cell
Cations- potassium, sodium, magnesium and calcium.
Anions- chloride anion, bicarbonate anion, hydrogen phosphate anion, dihydrogen phosphate anion, carbonate anion, phosphate anion and nitrate anion.
Let's consider the meaning of ions.
Ions, located on opposite sides of cell membranes, form the so-called transmembrane potential. Many ions are unevenly distributed between the cell and the environment. Thus, the concentration of potassium ions (K+) in the cell is 20-30 times higher than in the environment; and the concentration of sodium ions (Na+) is ten times lower in the cell than in the environment.
Thanks to existence concentration gradients, many vital processes are carried out, such as contraction of muscle fibers, excitation of nerve cells, and transfer of substances across the membrane.
Cations affect the viscosity and fluidity of the cytoplasm. Potassium ions reduce viscosity and increase fluidity, calcium ions (Ca2+) have the opposite effect on the cell cytoplasm.
Anions of weak acids - bicarbonate anion (HCO3-), hydrogen phosphate anion (HPO42-) - are involved in maintaining the acid-base balance of the cell, that is pHenvironment. According to their reaction, solutions can be sour, neutral And main.
The acidity or basicity of a solution is determined by the concentration of hydrogen ions in it (Fig. 3).
Rice. 3. Determination of the acidity of a solution using a universal indicator
This concentration is expressed using the pH indicator, the length of the scale is from 0 to 14. Neutral medium pH is about 7. Acidic medium is less than 7. Basic medium is more than 7. You can quickly determine the pH of the medium using indicator papers or strips (see video) .
We dip the indicator paper into the solution, then remove the strip and immediately compare the color of the indicator zone of the strip with the colors of the standard comparison scale that is included in the kit, assessing the similarity of the color and determining the pH value (see video).
3. pH of the environment and the role of ions in its maintenance
The pH value in the cell is approximately 7.
A change in pH in one direction or another has a detrimental effect on the cell, since the biochemical processes taking place in the cell immediately change.
The constancy of the cell pH is maintained thanks to buffer properties its contents. A buffer solution is a solution that maintains a constant pH value. Typically, a buffer system consists of a strong and weak electrolyte: a salt and a weak base or weak acid that form it.
The effect of a buffer solution is that it resists changes in the pH of the environment. A change in the pH of the medium can occur as a result of concentrating the solution or diluting it with water, acid or alkali. When acidity, that is, the concentration of hydrogen ions, increases, free anions, the source of which is the salt, interact with protons and remove them from the solution. When acidity decreases, the tendency to release protons increases. In this way, the pH is maintained at a certain level, that is, the concentration of protons is maintained at a certain constant level.
Some organic compounds, in particular proteins, also have buffering properties.
Cations of magnesium, calcium, iron, zinc, cobalt, manganese are part of enzymes and vitamins (see video).
Metal cations are part of hormones.
Zinc is part of insulin. Insulin is a pancreatic hormone that regulates blood glucose levels.
Magnesium is part of chlorophyll.
Iron is part of hemoglobin.
With a lack of these cations, the vital processes of the cell are disrupted.
4. Metal ions as cofactors
The importance of sodium and potassium ions
Sodium and potassium ions are distributed throughout the body, while sodium ions are mainly included in the intercellular fluid, and potassium ions are contained inside cells: 95% of ions potassium contained inside cells, and 95% of ions sodium contained in intercellular fluids(Fig. 4).
Associated with sodium ions osmotic pressure fluids, tissue water retention, and transport, or transport substances such as amino acids and sugars through the membrane.
The importance of calcium in the human body
Calcium is one of the most abundant elements in the human body. The bulk of calcium is found in bones and teeth. The fraction outside bone calcium makes up 1% of the total amount of calcium in the body. Extraosseous calcium affects blood clotting, as well as neuromuscular excitability and muscle fiber contraction.
Phosphate buffer system
The phosphate buffer system plays a role in maintaining the acid-base balance of the body; in addition, it maintains the balance in the lumen of the kidney tubules, as well as intracellular fluid.
The phosphate buffer system consists of dihydrogen phosphate and hydrogen phosphate. Hydrogen phosphate binds, that is, neutralizes the proton. Dihydrogen phosphate releases a proton and interacts with alkaline products entering the blood.
The phosphate buffer system is part of the blood buffer system (Fig. 5).
Blood buffer system
In the human body, there are always certain conditions for a shift in the normal reaction of the tissue environment, for example, blood, towards acidosis (acidification) or alkalosis (deoxidation - an upward shift in pH).
Various products enter the blood, for example, lactic acid, phosphoric acid, sulfurous acid, formed as a result of the oxidation of organophosphorus compounds or sulfur-containing proteins. In this case, the blood reaction may shift towards acidic foods.
When eating meat products, acidic compounds enter the blood. When eating plant foods, bases enter the blood.
However, the pH of the blood remains at a certain constant level.
There are in the blood buffer systems, which maintain pH at a certain level.
Blood buffer systems include:
Carbonate buffer system,
Phosphate buffer system,
Hemoglobin buffer system,
Plasma protein buffer system (Fig. 6).
The interaction of these buffer systems creates a certain constant pH of the blood.
Thus, today we looked at minerals and their role in the life of the cell.
Homework
What chemicals are called minerals? What is the importance of minerals for living organisms? What substances do living organisms mainly consist of? What cations are found in living organisms? What are their functions? What anions are found in living organisms? What is their role? What is a buffer system? What blood buffer systems do you know? What is the content of minerals in the body related to?
1. Chemical composition of living organisms.
2. Wikipedia.
3. Biology and medicine.
4. Educational center.
Bibliography
1. Kamensky A. A., Kriksunov E. A., Pasechnik V. V. General biology 10-11 grade Bustard, 2005.
2. Biology. Grade 10. General biology. Basic level / P. V. Izhevsky, O. A. Kornilova, T. E. Loshchilina and others - 2nd ed., revised. - Ventana-Graf, 2010. - 224 pp.
3. Belyaev D.K. Biology 10-11 grade. General biology. A basic level of. - 11th ed., stereotype. - M.: Education, 2012. - 304 p.
4. Agafonova I. B., Zakharova E. T., Sivoglazov V. I. Biology 10-11 grade. General biology. A basic level of. - 6th ed., add. - Bustard, 2010. - 384 p.
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.
>>> microelements
Minerals play an extremely important role in the life of living organisms. Along with organic substances, minerals are part of organs and tissues, and also participate in the metabolic process.
In total, up to 70 chemical elements are determined in the human body. Of these, 43 elements are absolutely necessary for normal metabolism.
All mineral substances, based on their quantitative content in the human body, are usually divided into several subgroups: macroelements, microelements and ultraelements.
Macronutrients are a group of inorganic chemicals present in the body in significant quantities (from several tens of grams to several kilograms). The group of macroelements includes sodium, potassium, calcium, phosphorus, etc.
Microelements found in the body in much smaller quantities (from several grams to tenths of a gram or less). These substances include: iron, manganese, copper, zinc, cobalt, molybdenum, silicon, fluorine, iodine, etc. A special subgroup of microelements are ultramicroelements, contained in the body in extremely small quantities (gold, uranium, mercury, etc.).
The role of minerals in the body
Mineral (inorganic) substances included in the structure of the body perform many important functions. Many macro and microelements are cofactors for enzymes and vitamins. This means that without mineral molecules, vitamins and enzymes are inactive and cannot catalyze biochemical reactions (the main role of enzymes and vitamins). Activation of enzymes occurs through the addition of atoms of inorganic (mineral) substances to their molecules, while the attached atom of an inorganic substance becomes the active center of the entire enzymatic complex. For example, iron from the hemoglobin molecule is capable of binding oxygen in order to transfer it to tissues; many digestive enzymes (pepsin, trypsin) require the addition of a zinc atom for activation, etc.
Many minerals are essential structural elements of the body - calcium and phosphorus make up the bulk of the mineral matter of bones and teeth, sodium and chlorine are the main ions of plasma, and potassium is found in large quantities inside living cells.
The entire set of macro and microelements ensures the processes of growth and development of the body. Minerals play an important role in regulating immune processes, maintaining the integrity of cell membranes, and ensuring tissue respiration.
Maintaining the constancy of the internal environment (homeostasis) of the body involves, first of all, maintaining the qualitative and quantitative content of minerals in tissues and organs at the physiological level. Even small deviations from the norm can lead to the most severe consequences for the health of the body.
Sources of minerals
The main source of minerals for humans is consumed water and food. Some mineral elements are ubiquitous, while others are found less frequently and in smaller quantities. Nowadays, given the disturbed ecology, the best source may be dietary supplements (dietary additives) and purified mineralized water.
Different foods contain different amounts of minerals. For example, cow's milk and dairy products contain more than 20 different minerals, the most important of which are iron, manganese, fluorine, zinc, and iodine. Meat and meat products contain microelements such as silver, titanium, copper, zinc, and seafood products - iodine, fluorine, nickel.
As mentioned above, the constancy of the internal environment (the content of various substances in the body) is of great importance for the normal functioning of the body. Despite the widespread occurrence of minerals in nature, disorders in the body associated with their deficiency (or, less commonly, with excess) are quite common. Diseases caused by a lack of minerals most often occur in certain regions of the globe, where, due to geological features, the natural concentration of a particular microelement is lower than in other areas. The so-called endemic zones of iodine deficiency are well known, in which such a disease as Goiter often occurs - a consequence of iodine deficiency.
However, much more often, a deficiency of minerals in the body occurs due to improper (unbalanced) nutrition, as well as during certain periods of life and in certain physiological and pathological conditions, when the need for minerals increases (growth period in children, pregnancy, breastfeeding, various acute and chronic diseases, menopause, etc.).
Brief characteristics of the most important minerals
Sodium- is the most common ion in plasma - the liquid part of the blood. This element accounts for the main share in the creation of plasma osmotic pressure. Maintaining normal osmotic pressure and circulating blood volume is a vital process that is realized mainly through the regulation of absorption or secretion (excretion) of sodium at the kidney level. When the volume of circulating blood decreases (for example, due to dehydration or after blood loss), a complex process is launched at the level of the kidneys, the purpose of which is to preserve and accumulate sodium ions in the body. In parallel with sodium ions, water is retained in the body (metal ions attract water molecules), as a result of which the volume of circulating blood is restored. Sodium is also involved in the electrical activity of nerve and muscle tissue. Due to the difference in sodium concentration between the blood and the intracellular environment, living cells can generate electrical current that underlies the activity of the nervous system, muscles and other organs. Sodium deficiency is very rare. It usually occurs when there is severe dehydration or major blood loss. The abundance of sodium in nature (table salt consists of sodium and chlorine) makes it possible to quickly replenish the body's reserves of this element. For some diseases (for example, hypertension), it is recommended to reduce salt intake (and therefore sodium) in order to slightly reduce circulating blood volume and lower blood pressure.
Potassium– is the main ion of the intracellular environment. Its concentration in the blood is many times less than inside cells. This fact is very important for the normal functioning of body cells. Like sodium, potassium is involved in the regulation of electrical activity of organs and tissues. The concentration of potassium in the blood and inside cells is maintained with great precision. Even small changes in the concentration of this element in the blood can cause serious disturbances in the functioning of internal organs (for example, the heart). Compared to sodium, potassium is less abundant in nature, but occurs in sufficient quantities. The main source of potassium for humans is fresh vegetables and fruits.
Calcium. The total mass of calcium in the adult human body is approximately 4 kilograms. Moreover, its main part is concentrated in bone tissue. Salts of calcium and phosphoric acid are the mineral basis of bones. In addition to minerals, bones also contain a certain amount of proteins, which form a kind of network on which mineral salts are deposited. Proteins give bones flexibility and elasticity, and mineral salts give them hardness and rigidity. Several grams of calcium are found in various organs and tissues. Here calcium plays the role of a regulator of intracellular processes. For example, calcium is involved in the mechanisms of transmission of nerve impulses from one nerve cell to another, participates in the mechanism of muscle and heart contraction, etc. The main source of calcium for humans is products of animal origin. Dairy products are especially rich in calcium. Calcium is absolutely necessary for the normal functioning of the metabolic process. Calcium deficiency is quite common. Most often it occurs due to poor nutrition (consuming small amounts of dairy products), as well as during pregnancy or breastfeeding. In children, calcium deficiency can develop during periods of intensive growth.
Iron. The adult human body contains about 4 grams of iron, with the bulk of it concentrated in the blood. Iron is an essential component of hemoglobin, the pigment of red blood cells that carries oxygen from the lungs to the tissues. Iron is also part of the enzymes that ensure cellular respiration (oxygen consumption by cells). The main source of iron for humans is food products of plant and animal origin. Apples, pomegranates, meat, and liver are rich in iron. Iron deficiency is manifested by anemia, as well as flaking of the skin, splitting of nails, cracks on the lips, and brittle hair. Most often, children and women of childbearing age suffer from iron deficiency. The cause of iron deficiency in children is poor nutrition and rapid growth of the body. In women, iron deficiency develops due to constant blood loss during menstruation. Iron deficiency is especially dangerous during pregnancy. Anemia, as a manifestation of iron deficiency, can even cause fetal death due to lack of oxygen.
Various diseases of the digestive tract (chronic gastritis, enteritis) can also contribute to the development of iron deficiency.
Iodine– is an essential microelement for humans. The main role of iodine in the human body is that iodine is the active part of thyroid hormones. Thyroid hormones regulate the body's energy processes - heat production, growth and development. With a lack of iodine, a serious condition occurs - hypothyroidism, so named because of the lack of thyroid hormones (iodine is necessary for their synthesis). The main sources of iodine for humans are milk, meat, fresh vegetables, fish and seafood. Iodine deficiency occurs mainly due to poor diet. In some regions of the globe (for example, the Urals), hypothyroidism occurs especially often. This is due to a lack of iodine content in soil and water.
Fluorine beneficial to the body only in small quantities. At low concentrations, fluoride stimulates the development and growth of teeth, bone tissue, the formation of blood cells, and increases immunity. A lack of fluoride increases the risk of caries (especially in children) and negatively affects the immune system. In large doses, fluoride can cause the disease fluorosis, which manifests itself as skeletal changes. The main sources of fluoride are fresh vegetables and milk, as well as drinking water.
Copper. The role of copper in the body is to activate tissue enzymes that are involved in cell respiration and the transformation of substances. It is also important to note the positive effect of copper on the process of hematopoiesis. With the help of copper, iron is transferred to the bone marrow and red blood cells mature. With a lack of copper, the development of bone and connective tissue is impaired, the mental development of children is also inhibited, the liver and spleen are enlarged, and anemia develops. Bread and flour products, tea, coffee, fruits and mushrooms are the main sources of copper for humans.
Zinc is part of many enzymes, has a stimulating effect on the process of puberty, bone formation, and the breakdown of adipose tissue. Zinc deficiency develops quite rarely. Sometimes zinc deficiency occurs when excess consumption of flour products interferes with the absorption of zinc from the intestines. A lack of zinc (especially in childhood) can lead to severe developmental disorders: inhibition of puberty, hair loss, skeletal deformation. Sufficient amounts of zinc for humans are found in animal liver, meat, egg yolks, cheeses, and peas.
Cobalt– is a factor in the activation of vitamin B12, therefore this element is indispensable for the normal course of the process of blood formation. Cobalt also stimulates protein synthesis and muscle growth, and activates some enzymes that process carbohydrates. Cobalt deficiency can manifest itself as anemia (anemia). The main sources of cobalt are bread and flour products, fruits and vegetables, milk, and legumes.
Bibliography:
- Idz M.D. Vitamins and minerals, St. Petersburg. : Set, 1995
- Mindell E. Handbook of vitamins and minerals, M.: Medicine and nutrition: Tekhlit, 1997
- Beyul E.A Handbook of Dietetics, M.: Medicine, 1992
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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 blood clotting processes, 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
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, the pH can vary greatly, and most enzymes only work 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.”