Metabolism and energy, or metabolism, - a set of chemical and physical transformations of substances and energy that occur in a living organism and ensure its vital activity. The exchange of matter and energy is a single whole and obeys the law of conservation of matter and energy.
Metabolism consists of the processes of assimilation and dissimilation. Assimilation (anabolism)- the process of assimilation of substances by the body, in which energy is consumed. Dissimilation (catabolism)- the process of disintegration of complex organic compounds flowing with the release of energy.
The only source of energy for the human body is oxidation organic matter coming with food. When splitting food products to the final elements - carbon dioxide and water - energy is released, part of which goes into mechanical work performed by the muscles, the other part is used to synthesize more complex compounds or accumulate in special high-energy compounds.
Macroergic compounds substances are called substances, the splitting of which is accompanied by the release of a large amount of energy. In the human body, the role of macroergic compounds is performed by adenosine triphosphoric acid (ATP) and creatine phosphate (CP).
PROTEIN METABOLISM.
proteins(proteins) are high-molecular compounds built from amino acids. Functions:
Structural, or plastic, function is that proteins are the main integral part all cells and intercellular structures. catalytic or enzymatic The function of proteins is their ability to speed up biochemical reactions in the body.
Protective function proteins is manifested in the formation of immune bodies (antibodies) when a foreign protein (for example, bacteria) enters the body. In addition, proteins bind toxins and poisons that enter the body and provide blood clotting and stop bleeding in wounds.
transport function is the transfer of many substances. The most important function of proteins is the transmission hereditary properties in which nucleoproteins play a leading role. There are two main types of nucleic acids: ribonucleic acids (RNA) and deoxyribonucleic acids (DNA).
Regulatory function proteins is aimed at maintaining biological constants in the body.
Energy role proteins is to provide energy for all life processes in the body of animals and humans. When 1 g of protein is oxidized, on average, energy is released equal to 16.7 kJ (4.0 kcal).
Need for proteins. The body is constantly breaking down and synthesizing proteins. Food proteins are the only source of new protein synthesis. In the digestive tract, proteins are broken down by enzymes into amino acids and absorbed in the small intestine. From amino acids and the simplest peptides, cells synthesize their own protein, which is characteristic only for a given organism. Proteins cannot be replaced by other nutrients, since their synthesis in the body is possible only from amino acids. At the same time, protein can replace fats and carbohydrates, i.e., be used for the synthesis of these compounds.
The biological value of proteins. Some amino acids cannot be synthesized in the human body and must be supplied with food in finished form. These amino acids are called indispensable or vital. These include: valine, methionine, threonine, leucine, isoleucine, phenylalanine, tryptophan and lysine, and in children also arginine and histidine. The lack of essential acids in food leads to violations of protein metabolism in the body. Non-essential amino acids are mainly synthesized in the body.
Proteins containing all the necessary set of amino acids are called biologically complete. The highest biological value of proteins in milk, eggs, fish, meat. Biologically inferior proteins are proteins that lack at least one amino acid that cannot be synthesized in the body. Incomplete proteins are proteins of corn, wheat, barley.
nitrogen balance. The nitrogen balance is the difference between the amount of nitrogen contained in human food and its level in excretions.
Nitrogen balance- a state in which the amount of nitrogen excreted is equal to the amount that enters the body. Nitrogen balance is observed in a healthy adult.
positive nitrogen balance- a condition in which the amount of nitrogen in the excretions of the body is much less than its content in food, that is, nitrogen retention in the body is observed. A positive nitrogen balance is observed in children due to increased growth, in women during pregnancy, with increased sports training, leading to an increase in muscle tissue, during the healing of massive wounds or recovery from serious illnesses.
nitrogen deficiency(negative nitrogen balance) is noted when the amount of nitrogen released is greater than its content in food entering the body. Negative nitrousbalance is observed with protein starvation, feverish conditions, disorders of neuroendocrine regulation of protein metabolism.
Protein breakdown and urea synthesis. The most important nitrogenous breakdown products of proteins that are excreted in the urine and sweat are urea, uric acid and ammonia.
FAT METABOLISM.
Fats divide on the simple lipids(neutral fats, waxes), complex lipids(phospholipids,glycolipids, sulfolipids) and steroids(cholesterol andetc.). The bulk of lipids in the human body is represented by neutral fats. Neutral Fats human food are an important source of energy. When 1 g of fat is oxidized, 37.7 kJ (9.0 kcal) of energy is released.
The daily requirement of an adult in neutral fat is 70-80 g, children 3-10 years old - 26-30 g.
Energy-neutral fats can be replaced by carbohydrates. However, there are unsaturated fatty acids - linoleic, linolenic and arachidonic, which must be contained in the human diet, they are called not essential fatty acids.
Neutral fats, which are part of human food and tissues, are mainly represented by triglycerides containing fatty acids - palmitic,stearic, oleic, linoleic and linolenic.
The liver plays an important role in fat metabolism. The liver is the main organ in which the formation of ketone bodies (beta-hydroxybutyric, acetoacetic acids, acetone) occurs. Ketone bodies are used as an energy source.
Phospho- and glycolipids are part of all cells, but mainly in the composition of nerve cells. The liver is practically the only organ that maintains the level of phospholipids in the blood. Cholesterol and other steroids can be ingested or synthesized in the body. The main site of cholesterol synthesis is the liver.
In adipose tissue, neutral fat is deposited in the form of triglycerides.
Formation of fats from carbohydrates. Excess consumption of carbohydrates with food leads to the deposition of fat in the body. Normally, in humans, 25-30% of the carbohydrates in food are converted into fats.
Formation of fats from proteins. Proteins are plastic material. Only under extreme circumstances are proteins used for energy purposes. The conversion of protein to fatty acids occurs most likely through the formation of carbohydrates.
CARBOHYDRATE METABOLISM.
The biological role of carbohydrates for the human body is determined primarily by their energy function. The energy value of 1 g of carbohydrates is 16.7 kJ (4.0 kcal). Carbohydrates are a direct source of energy for all cells of the body, perform plastic and supporting functions.
The daily requirement of an adult in carbohydrates is about 0.5 kg. The main part of them (about 70%) is oxidized in the tissues to water and carbon dioxide. About 25-28% of dietary glucose is converted into fat and only 2-5% is synthesized into glycogen - the body's reserve carbohydrate.
Monosaccharides are the only form of carbohydrate that can be absorbed. They are absorbed mainly in the small intestine, and are transported by the bloodstream to the liver and tissues. Glycogen is synthesized from glucose in the liver. This process is called glycogenesis. Glycogen can be broken down into glucose. This phenomenon is called glycogenolysis. In the liver, the neoplasm of carbohydrates is possible from their decay products (pyruvic or lactic acid), as well as from the decay products of fats and proteins (keto acids), which is designated as glyconeogenesis. Glycogenesis, glycogenolysis and glyconeogenesis are closely interrelated processes occurring in the liver that ensure optimal blood sugar levels.
in muscles, as well asin the liver, glycogen is synthesized. The breakdown of glycogen is one of the sources of energy for muscle contraction. With the breakdown of muscle glycogen, the process goes to the formation of pyruvic and lactic acids. This process is called glycolysis. In the resting phase, glycogen is re-synthesized from lactic acid in muscle tissue.
Brain contains small reserves of carbohydrates and needs a constant supply of glucose. Glucose in the brain tissues is predominantly oxidized, and a small part of it is converted into lactic acid. The energy costs of the brain are covered exclusively by carbohydrates. A decrease in glucose intake to the brain is accompanied by a change in metabolic processes in the nervous tissue and a violation of brain functions.
Formation of carbohydrates from proteins and fats (glyconeogenesis). As a result of the conversion of amino acids, pyruvic acid is formed, while the oxidation of fatty acids produces acetylcoenzyme A, which can be converted into pyruvic acid, a precursor of glucose. It is the most important common pathway for carbohydrate biosynthesis.
Between the two main sources of energy - carbohydrates and fats - there is a close physiological relationship. An increase in blood glucose increases the biosynthesis of triglycerides and reduces the breakdown of fats in adipose tissue. Less free fatty acids enter the bloodstream. If hypoglycemia occurs, the process of triglyceride synthesis is inhibited, the breakdown of fats is accelerated, and free fatty acids enter the blood in large quantities.
WATER-SALT METABOLISM.
All chemical and physical chemical processes that occur in the body are carried out in the aquatic environment. Water performs the following important functions in the body functions: 1) serves as a solvent for food and metabolism; 2) transfers substances dissolved in it; 3) weakens the friction between the contacting surfaces in the human body; 4) participates in the regulation of body temperature due to high thermal conductivity, high heat of evaporation.
The total water content in the body of an adult is 50 —60% from its mass, that is, it reaches 40—45 l.
It is customary to divide water into intracellular, intracellular (72%) and extracellular, extracellular (28%). Extracellular water is located inside the vascular bed (in the composition of blood, lymph, cerebrospinal fluid) and in the intercellular space.
Water enters the body through the digestive tract in the form of liquid or water contained in densefood products. Some of the water is formed in the body itself in the process of metabolism.
With an excess of water in the body, there is general hyperhydration(water poisoning), with a lack of water, metabolism is disturbed. Loss of 10% of water leads to the condition dehydration(dehydration), with a loss of 20% of water, death occurs.
Along with water, minerals (salts) also enter the body. Near 4% dry mass of food should be mineral compounds.
An important function of electrolytes is their participation in enzymatic reactions.
Sodium ensures the constancy of the osmotic pressure of the extracellular fluid, participates in the creation of bioelectric membrane potential, in the regulation of the acid-base state.
Potassium provides osmotic pressure of intracellular fluid, stimulates the formation of acetylcholine. The lack of potassium ions inhibits anabolic processes in the body.
Chlorine is also the most important anion of the extracellular fluid, ensuring the constancy of osmotic pressure.
calcium and phosphorus are found mainly in bone tissue (over 90%). The content of calcium in plasma and blood is one of the biological constants, since even slight changes in the level of this ion can lead to severe consequences for the body. A decrease in blood calcium levels causes involuntary muscle contractions, convulsions, and death occurs due to respiratory arrest. An increase in the calcium content in the blood is accompanied by a decrease in the excitability of the nervous and muscle tissues, the appearance of paresis, paralysis, and the formation of kidney stones. Calcium is necessary for building bones, so it must be supplied in sufficient quantities in the body with food.
Phosphorus participates in the metabolism of many substances, as it is part of high-energy compounds (for example, ATP). Great importance has a deposition of phosphorus in the bones.
Iron is part of hemoglobin, myoglobin, responsible for tissue respiration, as well as in the composition of enzymes involved in redox reactions. Insufficient intake of iron in the body disrupts the synthesis of hemoglobin. A decrease in hemoglobin synthesis leads to anemia (anemia). The daily iron requirement for an adult is 10-30 mcg.
Iodine in the body is contained in a small amount. However, its significance is great. This is due to the fact that iodine is part of the thyroid hormones, which have a pronounced effect on all metabolic processes, growthand development of the body.
Education and energy consumption.
The energy released during the breakdown of organic substances accumulates in the form of ATP, the amount of which in the tissues of the body is maintained at high level. ATP is found in every cell in the body. Its largest amount is found in skeletal muscles - 0.2-0.5%. Any activity of the cell always exactly coincides in time with the breakdown of ATP.
Destroyed ATP molecules must be restored. This is due to the energy that is released during the breakdown of carbohydrates and other substances.
The amount of energy spent by the body can be judged by the amount of heat that it gives to the external environment.
Methods for measuring energy costs (direct and indirect calorimetry).
respiratory rate.
Direct calorimetry is based on the direct determination of the heat released during the life of the organism. A person is placed in a special calorimetric chamber, which takes into account the entire amount of heat given off by the human body. The heat generated by the body is absorbed by the water flowing through a system of pipes laid between the walls of the chamber. The method is very cumbersome, its application is possible in special scientific institutions. As a consequence, in practical medicine widely used indirect method calorimetry. The essence of this method lies in the fact that first determine the volume of pulmonary ventilation, and then - the amount of oxygen absorbed and carbon dioxide released. The ratio of the volume of carbon dioxide released to the volume of oxygen absorbed is called respiratory coefficient . The value of the respiratory coefficient can be used to judge the nature of oxidized substances in the body.
When oxidized carbohydrate respiratory coefficient is 1 as for complete oxidation of 1 molecule glucose carbon dioxide and water require 6 molecules of oxygen, while 6 molecules of carbon dioxide are released:
C 6 H12O 6 +60 2 \u003d 6C0 2 + 6H 2 0
The respiratory coefficient for protein oxidation is 0.8, for fat oxidation - 0.7.
Determination of energy consumption by gas exchange. Quantityheat released in the body when consuming 1 liter of oxygen - caloric equivalent of oxygen - depends on the oxidation of which substances oxygen is used. Caloric equivalent oxygen during the oxidation of carbohydrates is 21,13 kJ (5.05 kcal), proteins— 20.1 kJ (4.8 kcal), fat - 19.62 kJ (4.686 kcal).
Energy consumption in humans is defined as follows. A person breathes for 5 minutes through a mouthpiece (mouthpiece) taken into the mouth. The mouthpiece, connected to a bag made of rubberized fabric, has valves. They are arranged so what the person breathes freely atmospheric air, and exhales air into the bag. With the help of gas hours measure exhaled volume air. According to the indicators of the gas analyzer, the percentage of oxygen and carbon dioxide in the air inhaled and exhaled by a person is determined. Then the amount of absorbed oxygen and released carbon dioxide, as well as the respiratory coefficient, are calculated. Using the appropriate table, the caloric equivalent of oxygen is determined by the value of the respiratory coefficient and the energy consumption is determined.
Basic metabolism and its significance.
BX- the minimum amount of energy necessary to maintain the normal functioning of the body in a state of complete rest, with the exclusion of all internal and external influences, which could increase the level of metabolic processes. Basal metabolism is determined in the morning on an empty stomach (12-14 hours after the last meal), in the supine position, with complete relaxation of the muscles, in conditions of temperature comfort (18-20 ° C). The basic exchange of the amount of energy released by the body (kJ / day) is expressed.
In a state of complete physical and mental rest body expends energy on: 1) constantly occurring chemical processes; 2) mechanical work performed by individual organs (heart, respiratory muscles, blood vessels, intestines, etc.); 3) the constant activity of the glandular secretory apparatus.
Basal metabolism depends on age, height, body weight, sex. The most intensive basic metabolism per 1 kg of body weight is observed in children. With an increase in body weight, the basal metabolism increases. The average basal metabolic rate in a healthy person is approximately 4.2 kJ (1 kcal) in 1 hour per 1 kg of weight body.
In terms of energy consumption at rest, body tissues are heterogeneous. More actively use energy internal organs less active - muscle tissue.
The intensity of the basic metabolism in adipose tissue is 3 times lower than in the rest of the cell mass of the body. Lean people produce more heat per 1 kgbody weight than full.
Women have a lower basal metabolic rate than men. This is due to the fact that women have less mass and body surface. According to Rubner's rule, basal metabolism is approximately proportional to body surface area.
Seasonal fluctuations in the basal metabolic rate were noted - its increase in spring and decrease in winter. Muscular activity causes an increase in metabolism in proportion to the severity of the work performed.
Violations of the functions of organs and systems of the body lead to significant changes in the basic metabolism. With increased thyroid function, malaria, typhoid fever, tuberculosis, accompanied by fever, the basic metabolism increases.
Energy expenditure during exercise.
During muscular work, the energy costs of the body increase significantly. This increase in energy costs is a work increase, which is greater, the more intense the work.
Compared to sleep, slow walking increases energy consumption by 3 times, and when running short distances during competitions, more than 40 times.
During short-term loads, energy is expended due to the oxidation of carbohydrates. With prolonged muscle loads, the body breaks down mainly fats (80% of the total energy needed). In trained athletes, the energy of muscle contractions is provided solely by the oxidation of fats. For a person engaged in physical labor, energy costs increase in proportion to the intensity of labor.
NUTRITION.
Replenishment of energy costs of the body occurs due to nutrients. The food should contain proteins, carbohydrates, fats, mineral salts and vitamins in small quantities and in the correct ratio. digestibilitynutrients depend onfrom individual characteristics and the state of the body, on the quantity and quality of food, the ratio of its various components, the method of preparation. Plant foods are less digestible than animal products because plant foods contain more fiber.
The protein diet contributes to the implementation of the processes of absorption and digestibility of nutrients. With the predominance of carbohydrates in food, the absorption of proteins and fats decreases. Replacement herbal products products of animal origin enhances metabolic processes in the body. If instead of vegetable proteins meat or dairy products are given, and wheat instead of rye bread, then the digestibility of food products increases significantly.
So to ensure proper nutrition human, it is necessary to take into account the degree of assimilation of products by the body. In addition, food must necessarily contain all the essential (mandatory) nutrients: proteins and essential amino acids, vitamins,highly unsaturated fatty acids, minerals and water.
The bulk of food (75-80%) are carbohydrates and fats.
Diet- the amount and composition of food products needed by a person per day. It must replenish the body's daily energy costs and include all the nutrients in sufficient quantities.
To draw up diets, it is necessary to know the content of proteins, fats and carbohydrates in foods and their energy value. With these data, it is possible to draw up a scientifically based diet for people. different ages, gender and occupation.
Diet and its physiological significance. It is necessary to observe a certain diet, to organize it correctly: constant hours of eating, appropriate intervals between them, the distribution of the daily ration during the day. Eating should always be at a certain time at least 3 times a day: breakfast, lunch and dinner. Breakfast in terms of energy value should be about 30% of the total diet, lunch - 40-50%, and dinner - 20-25%. It is recommended to have dinner 3 hours before bedtime.
Proper nutrition ensures normal physical development and mental activity, increases efficiency, reactivity and resistance of the body to environmental influences.
According to the teachings of I.P. Pavlov about conditioned reflexes, the human body adapts to a certain meal time: an appetite appears and digestive juices begin to stand out. Correct intervals between meals ensure a feeling of satiety during this time.
Three meals a day is generally physiological. However, it is preferable to have four meals a day, which increases the absorption of nutrients, in particular proteins, does not feel hunger in the intervals between separate meals, and maintains a good appetite. In this case, the energy value of breakfast is 20%, lunch - 35%, afternoon tea - 15%, dinner - 25%.
Balanced diet. Nutrition is considered rational if the need for food in quantitative and qualitative terms is fully satisfied, all energy costs are reimbursed. It contributes to the proper growth and development of the body, increases its resistance to harmful influences. external environment, contributes to the development of the functional capabilities of the body and increases the intensity of labor. Rational nutrition involves the development of food rations and diets in relation to various contingents of the population and living conditions.
As already mentioned, the nutrition of a healthy person is built on the basis of daily food rations. The diet and diet of the patient is called a diet. Each diet has certain components of the diet and is characterized by the following features: 1) energy value; 2) chemical composition; 3) physical properties(volume, temperature, consistency); 4) power mode.
Regulation of metabolism and energy.
Conditioned reflex changes in metabolism and energy are observed in humans in pre-launch and pre-working states. Athletes before the start of the competition, and the worker before work, there is an increase in metabolism, body temperature, oxygen consumption increases and carbon dioxide is released. You can cause conditioned reflex changes in metabolism, energy and thermal processes people on verbal stimulus.
Influence of nervous systems for exchange and energy processes in the body carried out in several ways:
Immediate impact nervous system(through the hypothalamus, efferent nerves) to tissues and organs;
Indirect influence of the nervous system throughpituitary gland (somatotropin);
mediatedinfluence of the nervous system through tropic hormones pituitary gland and peripheral glands of the internal secretions;
Direct influencenervous system (hypothalamus) on the activity of endocrine glands and through them on metabolic processes in tissues and organs.
The main department of the central nervous system, which regulates all types of metabolic and energy processes, is hypothalamus. A pronounced effect on metabolic processes and heat generation is exerted by internal gland secretions. Hormones of the adrenal cortex and thyroid gland in large quantities increase catabolism, i.e., the breakdown of proteins.
In the body, the close interconnected influence of the nervous and endocrine systems on metabolic and energy processes is clearly manifested. Thus, excitation of the sympathetic nervous system not only has a direct stimulating effect on metabolic processes, but it also increases the secretion of thyroid and adrenal hormones (thyroxine and adrenaline). Due to this, the metabolism and energy metabolism is further enhanced. In addition, these hormones themselves increase the tone of the sympathetic division of the nervous system. Significant changes in metabolism and heat exchange occurs when there is a deficiency in the body of hormones of the endocrine glands. For example, a lack of thyroxin leads to a decrease in basal metabolism. This is due to a decrease in oxygen consumption by tissues and a weakening of heat generation. As a result, the body temperature drops.
The hormones of the endocrine glands are involved in the regulation of metabolism and energy by changing the permeability cell membranes(insulin), activating the enzyme systems of the body (adrenaline, glucagon, etc.) and influencing on their biosynthesis (glucocorticoids).
Thus, the regulation of metabolism and energy is carried out by the nervous and endocrine systems, which ensure the adaptation of the body to the changing conditions of its habitat.
The second branch of the biological cycle is destruction cycle, consisting of the processes of destruction of organic compounds and the transition of chemical elements from complex organic compounds to simple mineral ones, accompanied by the release of energy.
The processes of decomposition begin in the most living organisms and run parallel to photosynthesis. These are respiration processes, as a result of which part of the synthesized organic matter decomposes into primary products - carbon dioxide and water. But in plants, the synthesis of organic substances far exceeds their decomposition, and in general, plants accumulate these substances. The remaining part of the synthesized substance - the primary production - is oxidized gradually, moving from one trophic level to another. Animals, for which plants are the only primary source of chemical energy, decompose organic matter very intensively. The final products of this oxidation are also carbon dioxide and water.
But the main processes of decomposition are associated with the transformation of dead plant and animal remains. A specific group of organisms takes part in their decomposition - decomposers - fungi, actinomycetes, bacteria. On the last step dead organic residues are decomposed by microorganisms (to a lesser extent this occurs through abiotic oxidation). Using the chemical energy contained in organic compounds, microorganisms convert proteins, fats and carbohydrates into simple mineral compounds, which are returned to the atmosphere (carbon dioxide, water and ammonia) and to the soil (ash elements). Although this decomposition leads to the formation of new forms of living matter in the form of bodies of microorganisms, the total amount of organic matter decreases, since the main part of it is mineralized.
The set of processes of decomposition of organic substances, during which chemical elements are released from the composition of complex, energy-rich organic compounds and again form simpler and poorer energy mineral compounds, is called the mineralization of organic substances.
The rate of destruction of organic compounds obeys the laws of geographical zoning and increases with an increase in inflow solar energy. With a lack of heat and an excess of moisture, the annual plant litter does not have time to collapse, and excess mort-mass accumulates in the landscape, thick litter and peat deposits are formed. Under arid conditions with their high energy potential, the rate of destruction far exceeds production, and the accumulation of dead organic matter does not occur. Production and destruction processes are most balanced under conditions of optimum heat and moisture.
Depending on climatic conditions, the rate of decomposition of organic compounds is significantly different. The undecomposed and semi-decomposed part of plant and animal remains accumulates. M.A. Glazovskaya called this process detritogenesis. Its quantitative characteristics are of great geochemical significance and are characterized by the following indicators:
O1 - annual plant litter, O2 - green part of the litter, O3 - forest litter or felt, the ratio of O3 and O2 (OPI litter-litter index), proposed by L.E. Rodin and N.I. Bazilevich.
OPI \u003d O3 / O2 * 100%
These indicators vary significantly depending on the natural zone. For example, O1 is 1 centner/ha in takyrs, 10 centners/ha in arctic tundra, 250 centners/ha in tropical rainforests, and 15 centners/ha in dry steppes, 20 centners/ha in tropical rain forests, shrub tundra - 835 q/ha. The litter-litter index characterizes the intensity of decomposition processes and amounts to 2000–5000% in the shrub tundra, 100% in dry steppes, and 10% in humid tropical forests.
During decomposition, part of the organic residues passes into soil humus, its share is especially large under conditions of sufficient heat and a small moisture deficit, i. in steppe conditions, where humus reserves reach 600-1000t/ha. In the soils of broad-leaved forests, humus reserves are 300 t/ha, taiga forests - 100 t/ha, tundra - 70 t/ha. The values of undecomposed plant residues are reversed - in the steppes 4-10t/ha, taiga - 40-50t/ha, broad-leaved forests - 10-15 t/ha. The stocks of dead organic matter and the stock of biomass in plant organs are an important reserve of nutrients that ensures the stability of the biota to environmental fluctuations under conditions of intense abiogenic removal of ash and nitrogen nutrition elements.
In forest landscapes (under conditions of excessive moisture and intense runoff and loss of nutrients), the supply of ash elements in living matter and the litter that firmly holds the necessary elements provides a certain autonomy ( a high degree isolation) of the biological cycle. In the steppes, where vegetation is not able to accumulate reserves of living phytomass and the litter is rapidly destroyed, humus reserves are the reserve of mineral nutrition. For these landscapes, humus reserves provide a certain autonomy and stability. A guarantee of stability for wet landscapes equatorial forests, having neither a powerful litter nor humus reserves, is a large isolation of the biological cycle and a high rate of decomposition of organic compounds.
Thus, the process of mineralization enriches the landscape with free energy, which is carried by natural waters. They become more active and perform a huge chemical work. The presence of free energy makes the landscape a non-equilibrium system, but, despite this, it retains its appearance for a long time. This is explained not by thermodynamic equilibrium, but by the stationarity of the processes occurring in the landscape. The stability of the landscape is due to the fact that the expended excess energy is continuously replenished from the environment in an amount that compensates for its decrease in the landscape. Thus, biogenic landscape - self-developing self-regulating non-equilibrium stationary (sustainable) system(A.I. Perelman, N.S. Kasimov, 1999) .
The destruction cycle has a number of specific features:
1. Mineralization is aimed at reducing the complexity and diversity of the system, reducing the amount of complex biological information by increasing inorganic information.
2. The decomposition of organic compounds is characterized, in contrast to the processes of their formation, by repetition in time and space. For example, swamp waters with a high content of dissolved organic compounds and intensive migration of iron and manganese are typical for humid tropical conditions of the present and previous eras (Paleozoic and Mesozoic). The living matter of these epochs is different. At the same time, in one epoch in different natural zones, chemism natural waters, determined by the processes of decomposition of organic compounds, is the same (weakly mineralized and rich in dissolved organic matter waters of humid landscapes, and weakly alkaline oxygen class of waters of semiarid landscapes). Thus, the processes of decomposition and associated water migration are more uniform than the processes of formation of living matter. No matter how diverse living organisms are, after death their remains turn into the same simple mineral compounds - carbon dioxide and water, as well as substances of the humus type.
Mineralization processes play a significant role in the formation of the geochemical characteristics of the landscape. As a result of mineralization biogenic redistribution of chemical elements, formation of specific biogenic minerals, change chemical composition landscape waters.
The main mass of living matter is concentrated above the soil or in the upper humus horizon, and the mineralization of dead residues also occurs here. Therefore, after mineralization, biophilic elements accumulate in the upper part of the soil profile, the coefficient of biological absorption of which is greater than 1. The absorption of elements by plant roots occurs from the entire soil. Thus, plants play the role of a pump that redistributes chemical elements by extracting biophilic elements from the entire soil layer and accumulating them in the upper horizon. This mechanism is a negative bioinert feedback in the landscape, which contributes to the stabilization of both the soil and the entire landscape as a whole.
Mineralization is accompanied by the formation of two groups of biogenic minerals. Minerals of the first group are part of cellular secretions, skeleton, shell, shells, etc. These minerals have an organomorphic structure, i.e. retain the shape of the cells in which they originated. These minerals are called "bioliths". After the death of a living organism, bioliths enter the silts, soils, where they lose their organomorphic structure and acquire an earthy appearance. For example, shells of freshwater mollusks are preserved in the upper layers of alluvial deposits, while in the lower layers they turn into accumulations of powdered lime carbonate, partially retaining the shape of shells. The tissues of many plants contain calcite crystals (wood, earthy secretions on the surface of the leaves, calcareous material in the cell tissue), which, when decomposed, enrich the soil with calcium. The plants and diatoms of the steppes and mountain meadows are characterized by the accumulation of opal (Si2 nH2O) bodies - phytolitharians. After the decomposition of plant residues, opal loses water, organomorphic structure, turns into chalcedony, re-precipitates and enriches the soil with silicon dioxide (secondary quartz).
Another group of biogenic minerals arises outside the bodies of organisms from the products of their vital activity. Numerous studies (Polynov B.B., M.A. Glazovskaya) of both primitive soils of high mountains and well-developed soil profiles prove that the finely dispersed (clay) part of the soils was largely formed due to the decomposition of the remains of organisms, i.e. Clay minerals in soils are of biogenic origin. This probably explains the unity of clay minerals in soils formed on various rocks.
Thus, in the process of decomposition and further mineralization, there is a synthesis of specific organic compounds - humus, specific mineral compounds - clay minerals, as well as the release of the simplest inorganic compounds. These processes lead to a redistribution of chemical elements in the lithogenic basis of the landscape. The absorption of chemical elements from soils occurs from the entire soil profile. The decomposition of organic compounds is mainly in the upper horizon. Here, after mineralization, those chemical elements are accumulated that
The decomposition of organic matter largely determines the formation of the chemical composition of groundwater. Groundwater receives carbon dioxide released during the respiration of underground parts of plants and underground fauna, organic acids and their salts, as well as organomineral complexes and mineral compounds of nitrogen, phosphorus and sulfur formed from decomposition products. The composition of cations in groundwater reflects their biophilicity. For example, in most landscapes (in their waters), calcium predominates over magnesium, since the coefficient of biological absorption of calcium is greater than that of magnesium, and there is more of it in mineralization products, therefore, more of it enters groundwater. In general, in landscapes with a strong accumulation of organic matter, the composition of river waters weakly depends on the host rocks. There is a kind of averaging of the chemical composition of waters, they become more uniform, for example. In all landscapes of a humid climate, they are fresh bicarbonate-calcium. On the contrary, in landscapes poor in life (deserts, dry steppes), the composition of the waters depends on the composition of the host rocks and their solubility. Here there can be sulfate, in places and chloride waters, and among the cations the role of magnesium and sodium increases.
Thus, in different landscapes, both biochemical and physicochemical processes occurring simultaneously take part in the formation of the chemical composition of waters. These processes are interrelated and interdependent. In the first case, chemical element before getting into the landscape waters, it passes through the body of the organism and enters the water from living or dead organic matter, and in the second case, the dissolution of minerals, ion exchange and other reactions take place, in which organisms act only as a factor affecting the dissolving power of water . Both categories of processes are developed in all landscapes. But in some the leading value is the first, in others - the second.
Indicators of the intensity of decomposition processes.
The ratio of litter (O3) to the green part of the litter (O2) gives a good idea of the intensity of decomposition of organic substances.
| on the topic: "Metabolism" I option | Test in biology grade 9 on the topic: "Metabolism" II option |
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| Choose one correct answer from four possible 1. The breakdown of complex organic substances occurs in the process: a) anabolism; c) photosynthesis b) catabolism; d) symbiosis 2. Energy consumption occurs in the process: a) glycolysis c) photolysis b) catabolism; d) anabolism; 3. Photosynthesis is carried out: a) in ribosomes; c) in mitochondria b) in chloroplasts; d) in the cytoplasm 4. During photosynthesis, a) proteins c) carbohydrates 5. The starting material for photosynthesis is: a) water and oxygen c) carbohydrates 6. Anaerobic glycolysis is called: a) the totality of all reactions energy metabolism b) oxygen-free breakdown of glucose c) oxidative phosphorylation d) splitting of ATP 7. Proteins are formed during the process a) photosynthesis c) glycolysis
Process Type of metabolism a) synthesis complex substances from simple 1.energy | ||||
9. Define terms : heterotrophs, photolysis, metabolism
10.
What is the importance of photosynthesis?
I . Choose one correct answer from four possible
1. Synthesis of complex substances from simple ones occurs in the process:
a) anabolism; c) catabolism;
b) metabolism d) symbiosis
2. The release of energy occurs in the process:
a) hydrolysis c) metabolism
b) anabolism; d) catabolism;
3. The process of photosynthesis takes place
a) in the nucleus c) in the mitochondria
b) in the cytoplasm d) in chloroplasts
4. Carbohydrates are formed in the process
a) biosynthesis; c) photosynthesis
b) energy metabolism; d) fermentation
5. The final main product of photosynthesis is:
a) carbohydrates c) water and oxygen
b) fats d) water and carbon dioxide
6. The end products of oxygen breakdown of organic substances are:
a) ATP and water c) water and oxygen
b) fats d) water and carbon dioxide
7. During biosynthesis,
a) proteins c) carbohydrates
b) fats d) nucleic acids
8
.
Match between biological process and the type of exchange to which it refers
. Fill in the answer table
Type of metabolism Process1.energy a) breakdown of carbohydrates to carbon dioxide
2. plastic b) synthesis of complex substances from simple ones
c) protein synthesis from amino acids
d) the breakdown of complex substances into simple ones
e) synthesis of carbohydrates from carbon dioxide
9. Define terms : autotrophs, glycolysis, metabolism
10. Give a complete detailed answer to the question
What is the role of autotrophs in nature?
Importance of Nutrients
In all organisms living today, from the most primitive to the most complex - the human body - the metabolism and energy is the basis of life.
In the human body, in its organs, tissues, cells, there is a continuous process of creation, the formation of complex substances. At the same time, decay and destruction of complex organic substances that make up the cells of the body occur.
The work of organs is accompanied by their continuous renewal: some cells die, others replace them. In an adult, 1/20 of the skin epithelium, half of all epithelial cells of the digestive tract, about 25 g of blood, etc., die and are replaced during the day.
Growth, renewal of body cells is possible only if oxygen and nutrients are continuously supplied to the body. Nutrients - that building, plastic the material from which life is built.
Energy is needed to build new body cells, their continuous renewal, for the functioning of such organs as the heart, gastrointestinal tract, respiratory apparatus, kidneys, etc., as well as for a person to perform work. The body receives this energy from the breakdown of cell substances in the process of metabolism.
Thus, the nutrients entering the body serve not only as a plastic, building material, but also as a source of energy, which is so necessary for life.
Under metabolism understand the totality of changes that substances undergo from the moment they enter the digestive tract to the formation of final decay products excreted from the body.
Assimilation and dissimilation
Metabolism is a unity of two processes: assimilation and dissimilation. As a result of the process assimilation relatively simple products of digestion, entering the cells, undergo chemical transformations with the participation of enzymes and become like the substances necessary for the body. Dissimilation- the breakdown of complex organic substances that make up the cells of the body. Part of the decay products is reused by the body, part is excreted from the body.
The process of dissimilation also takes place with the participation of enzymes. During dissimilation, energy is released. It is due to this energy that new cells are built, old ones are renewed, the human heart functions, mental and physical work is performed.
The processes of assimilation and dissimilation are inseparable from each other. With the intensification of the process of assimilation, especially with the growth of a young organism, the process of dissimilation also intensifies.
Transformation of substances
Chemical transformations of nutrients begin in the digestive tract. Here, complex proteins, fats and carbohydrates are broken down into simpler ones that can be absorbed through the intestinal mucosa and become a building material in the process of assimilation. In the digestive tract, a small amount of energy is released during digestion. Substances that have entered the blood and lymph as a result of absorption are brought into the cells, where they undergo major changes. The resulting complex organic substances are part of the cells and take part in the implementation of their functions. The energy released during the breakdown of cell substances is used for the life of the organism. The metabolic products of various organs and tissues that are not used by the body are excreted from it.
The role of enzymes in intracellular metabolism
The main processes of transformation of substances take place inside the cells of our body. These processes underlie intracellular exchange. Numerous cell enzymes play a decisive role in intracellular metabolism. Due to their activity, complex transformations occur with cell substances, intramolecular chemical bonds in them are broken, which leads to the release of energy. Of particular importance here are the reactions of oxidation and reduction. The end products of oxidation processes in the cell are carbon dioxide and water. With the participation of special enzymes, other types are also carried out. chemical reactions in a cage.
The energy released during these reactions is used to build new substances in the cell, to maintain the vital processes of the organism. The main accumulator and energy carrier used in many synthetic processes is adenosine triphosphoric acid (ATP). The ATP molecule contains three phosphoric acid residues. ATP is used in all metabolic reactions that require energy. In the ATP molecule, this breaks chemical bond with one or two phosphoric acid residues, releasing the stored energy (cleavage of one phosphoric acid residue leads to the release of about 42,000 J per 1 gram-molecule).
1 option
1. Transcription during protein biosynthesis in the cell occurs
- At the core
- on ribosomes
- On channels of smooth ER
- On the membranes of the cisterns of the Golgi complex
2. During translation, the template for assembling the polypeptide chain of the protein is (at)
- Two strands of a DNA molecule
- One of the strands of the DNA molecule
- mRNA molecule
- either a DNA molecule or an mRNA
3. Energy exchange differs from plastic exchange in that during energy exchange,
- expenditure of energy stored in ATP
- energy storage in macroergic bonds of ATP
- synthesis of carbohydrates and lipids
- synthesis of proteins and nucleic acids
4. The involvement of organic substances in energy metabolism as they are exhausted occurs in the body in the following sequence:
- Carbohydrates - fats - proteins
- Fats - carbohydrates - proteins
- Proteins fats carbohydrates
- Carbohydrates - proteins - fats
5. critical role Molecules provide energy to the cell
- NADP
6. If the nucleotide composition of DNA is ATG-GCH-TAT, then the nucleotide composition of mRNA will be
- TAA-CGTs-UTA
- TAA-GCG-UTU
- UAC-CHC-AUA
- UAA-CHC-ATA
a) breathing
b) transcription;
c) glycolysis
a) in mitochondria;
b) in the cytoplasm;
c) in ribosomes
a) glycolysis;
b) breathing;
c) photosynthesis
a) sunny;
b) chemical;
c) thermal
11. Transcription occurs when:
a) photosynthesis;
B) catabolism;
c) anabolism
Test on the topic: "Metabolism"
Option 2
- Universal source of energy in the cell:
a) protein;
b) DNA;
c) RNA;
d) ATP
- The breakdown of complex organic substances occurs in the process:
a) anabolism;
b) catabolism;
c) photosynthesis
- Energy consumption occurs in the process:
a) anabolism;
b) catabolism;
c) glycolysis
- The process of translation during protein synthesis occurs:
a) in ribosomes;
b) in mitochondria;
B) in the nucleus
- The formation of i - RNA by "writing off" genetic information is called:
A) transcription;
B) broadcast;
B) reduplication
- Photosynthesis requires the presence of:
a) DNA;
b) RNA;
c) chlorophyll
- The light phase of photosynthesis occurs:
a) only in the light;
B) only in the dark;
C) light and dark
- The oxygen stage of energy metabolism is called:
a) breathing
B) transcription;
B) glycolysis
- Glycolysis occurs:
a) in mitochondria;
b) in the cytoplasm;
c) in ribosomes
- Photosynthesis releases a by-product:
A) glucose;
B) water;
B) oxygen
- Energy exchange uses energy:
A) sunny
B) chemical;
B) thermal
3 option
1. The synthesis of complex organic substances occurs in the process:
a) anabolism;
b) catabolism;
c) digestion
2. The release of energy occurs in the process:
a) anabolism;
b) catabolism;
c) broadcasts
3. The process of transcription during protein biosynthesis occurs:
a) in ribosomes;
b) in mitochondria;
c) in the nucleus
4. The creation of a polymer chain from amino acids is called:
a) transcription;
b) broadcast;
B) reduplication
5. Photosynthesis is carried out:
a) in ribosomes;
b) in chloroplasts;
B) in mitochondria
6. The dark phase of photosynthesis occurs:
a) only in the light;
b) only in the dark;
C) light and dark
7. The oxygen-free stage of energy metabolism is called:
a) breathing
b) transcription;
c) glycolysis
8. Oxygen oxidation occurs:
a) in mitochondria;
b) in the cytoplasm;
c) in ribosomes
9. The formation of glucose from carbon dioxide and water occurs when:
a) glycolysis;
b) breathing;
c) photosynthesis
10. Photosynthesis uses energy:
a) sunny;
b) chemical;
c) thermal
11. The replication process is typical for:
a) RNA;
B) DNA;
B) protein
Test on the topic: "Metabolism".
4 option
1. ATP synthesis does not involve such a cell structure as:
A - cytoplasm
B - core
B - mitochondria
G - chloroplasts
2. Anaerobic glycolysis is called:
B - oxidative phosphorylation
G - splitting of ATP
3. The end products of oxygen oxidation of organic substances are:
A - ATP and water
B - water and carbon dioxide
D - ATP and oxygen
4. The energy of glucose oxidation goes to:
A - the formation of oxygen
B - decay of molecules - carriers of hydrogen
B - ATP synthesis, and then used by the body
G - synthesis of carbohydrates
5. In the process of energy metabolism is not formed:
A is glycogen.
B - water
B - carbon dioxide
G - ATP
6. Aerobic glycolysis goes:
A - in the cytoplasm
B - in mitochondria
G - on ribosomes
7. The starting material for photosynthesis is:
A - oxygen and carbon dioxide
B - water and oxygen
B - carbon dioxide and water
G - carbohydrates
8. The energy of excited electrons in the light stage of photosynthesis is used for:
A - ATP synthesis
B - glucose synthesis
B - protein synthesis
G - breakdown of carbohydrates
9. The formation of glucose from carbon dioxide and water occurs when:
a) glycolysis;
b) breathing;
c) photosynthesis
10. Photosynthesis uses energy:
a) sunny;
b) chemical;
c) thermal
Test on the topic: "Metabolism".
5 option
1. Photolysis of water is the reaction:
A - 4H + + e + O 2 \u003d 2H 2 O
B - 6CO 2 + 6H 2 O \u003d C 6 H 12 O 6
B - 2H 2 O \u003d 4H + + 4e + O 2
G - C 6 H 12 O 6 \u003d CO 2 + H 2 O
2. In the light phase of photosynthesis does not occur:
A - the formation of glucose
B - photolysis of water
B - ATP synthesis
G - formations of NADP*N
3. As a result of photosynthesis in chloroplasts, the following is formed:
A - carbon dioxide and oxygen
B - glucose, ATP, oxygen
B - chlorophyll, water, oxygen
D - carbon dioxide, ATP, oxygen
4. Transcription is a process:
A - synthesis of mRNA on one of the DNA strands
B - DNA duplication
B - reading information from i-RNA
D - attachment of t-RNA to an amino acid
5. Synthesis of proteins on ribosomes occurs in:
A - all existing organisms
B - all except mushrooms
B - all except prokaryotes
G - plants and animals
6. The main event of the interphase is:
A - mutation process
B - doubling of hereditary material
B - division of the cell nucleus
G - reduction of hereditary material by half
7. Of the cells listed below, mitosis does not divide:
A - fertilized eggs
B - disputes
B - spermatozoa
B - epithelial cells
8. Oxygen in the process of breathing is absorbed by:
A - animals
B - plants
B - anaerobic bacteria
G - A+B
9. Plastic exchange includes:
A - anaerobic glycolysis
B - protein biosynthesis
B - biosynthesis of fats
G – B+V
10. The dark phase of photosynthesis occurs:
a) only in the light;
b) only in the dark;
C) light and dark
Test on the topic: "Metabolism".
6 option
1. ATP synthesis involves such a cell structure as:
A is a ribosome
B - core
B - mitochondria
G - lysosome
2. Aerobic glycolysis is called:
A - the totality of all reactions of energy metabolism
B - anoxic breakdown of glucose
B - oxygen breakdown of glucose
G - splitting of ATP
3. The end product of oxygen-free oxidation of organic substances is:
A - ATP and water
B - oxygen and carbon dioxide
B - water and carbon dioxide
G - pyruvic acid
4. In the process of anaerobic glycolysis,
A - 2 ATP molecules
B - 4 ATP molecules
B - 36 ATP molecules
D - 38 ATP molecules
5. Oxygen is released in:
A - dark phase of photosynthesis
B - light phase of photosynthesis
B - anaerobic glycolysis
G - aerobic glycolysis
6. Anaerobic glycolysis goes:
A - in the cytoplasm
B - in mitochondria
B - in the digestive system
G - on ribosomes
7. In the process of energy metabolism is not formed:
A is glycogen.
B - water
B - carbon dioxide
G - ATP
8. Reactions of photosynthesis for which light is really necessary are:
A - absorption of carbon dioxide
B - glucose synthesis
B - synthesis of ATP and NADP*H
G - the formation of starch
9. Photolysis of water is carried out:
A - in the light phase of photosynthesis
B - in the dark phase of photosynthesis
B - with anaerobic glycolysis
D - with aerobic glycolysis
10. The sequence of amino acids in hemoglobin molecules of cows and humans:
A - do not differ
B - there are differences
B - a fundamentally different structure
G - different amino acids