Body metabolism definition. What is metabolism and what are the causes of its violation? What affects the speed of metabolic processes

General concept of metabolism and energy The human body, like all living organisms, exists as an open energy system. This means that the body is constantly losing substance in the form of fairly simple chemical compounds. At the same time, energy is removed from the body. But the body is a stable energy system, so the loss of matter and energy is replenished by their constant absorption from the environment. Thus, through the human body there is a constant flow of matter and the energy contained in it. This continuous flow is one of the most important properties of living organisms and is called metabolism and energy, or metabolism.

The substance entering the body contains chemical energy (the energy of intramolecular chemical bonds). This energy is converted in the body into the chemical energy of other compounds, as well as into thermal, mechanical and electrical energy. Little electrical energy is produced in the body, but it is important for the functioning of the nervous and muscular systems.

Metabolism is a single process that takes place at the level of the whole organism, it consists of metabolic processes occurring in each individual cell. The essence of metabolism is the whole variety of transformations of substances in the body, which occur either with the expenditure or with the release of energy. Therefore, the overall process of metabolism has two sides, inextricably linked:

Anabolism (assimilation, plastic exchange) is a set of synthesis reactions occurring in cells. At the same time, more complex substances are synthesized from simpler substances. Anabolism reactions come at an energy cost. The main source of energy for anabolism reactions is ATP. An example of such reactions is protein biosynthesis, which occurs in all cells. The starting materials for anabolism are nutrients that enter the body with food and are formed as a result of the digestive process. As a result of anabolic reactions, there is a constant self-renewal, growth and development of the body. In addition, anabolism reactions are suppliers of organic compounds for catabolism processes.

Catabolism (dissimilation, energy metabolism) is a set of reactions of splitting and decay of more complex organic substances to simpler ones, up to carbon dioxide and water. These reactions go with the release of energy, about half of which is converted into heat and spent on maintaining body temperature, and the second half of the energy is stored in the form of high-energy bonds in ATP molecules, which is used in synthesis reactions.

The main organic substances that make up the human body are proteins, carbohydrates, fats, nucleic acids, while some substances can be converted into others, for example, carbohydrates into fats and vice versa, proteins can be converted into fats and carbohydrates. The inorganic substances of the body are water and mineral salts. A complete, balanced diet should contain organic matter in sufficient quantity and quality, and it should also contain the necessary mineral salts and water and vitamins. There are about 60 nutrients that require balance.

Monotonous nutrition, leading to the exclusion of individual components, causes metabolic disorders. It is customary to distinguish protein, carbohydrate, fat and water-salt metabolism. The energy value of food is measured in kilocalories (kcal). A person's daily energy requirement averages about 3,100 kilojoules. This value depends on gender, age, physical and emotional activity. Especially high energy costs in terms of body weight in children 1-5 years old due to the high activity of metabolic processes.

Protein metabolism Among all the organic compounds that make up the human body, proteins account for the largest amount. The functions of proteins in the body are very diverse: structural (they are part of cell membranes, form a cytoskeleton); catalytic (enzyme proteins); regulatory (proteins - hormones); transport (albumins and globulins of blood plasma, hemoglobin of erythrocytes); protective (proteins - antibodies, proteins of the blood coagulation system); receptor, signal (proteins of membranes of receptor endings); contractile (actin and myosin of muscle cells, tubulin protein of flagella and cilia); energy (liberation of energy during the breakdown of proteins);

Proteins are of particular importance in a balanced diet, since they are not synthesized in the human body from other organic compounds and must be ingested as part of food. From a chemical point of view, proteins are polymeric compounds consisting of amino acids. In the human digestive tract, food proteins are broken down into amino acids, from which their own proteins are then synthesized in the cells of the body. Human proteins contain 22 different amino acids. All amino acids are divided into essential and non-essential.

Replaceable can be formed in the human body from other amino acids. Essential amino acids cannot be synthesized by the human body and therefore must be obtained from food. In the body of an adult, 14 amino acids can be synthesized. There are 10 essential amino acids in children, and 8 in adults (arginine, valine, leucine, isoleucine, etc.). The lack or absence of any one essential amino acid leads to a slowdown and even cessation of growth and development. In this regard, there is the concept of the biological value of proteins.

Proteins that contain all the essential amino acids and in sufficient quantities are called complete proteins. These are animal proteins (proteins of meat, fish, eggs, milk). Proteins that do not contain all the essential amino acids are called incomplete. These are proteins of plant origin (except potato proteins).

Food proteins under the action of proteolytic enzymes, which are part of the digestive juices, are broken down into amino acids and absorbed through the intestinal walls into the blood. With the blood flow, amino acids enter the cells of the body and participate in further transformations (protein biosynthesis, conversion into other amino acids, etc.).

Complete oxidation of 1 gram of proteins to carbon dioxide, water and urea is accompanied by the release of 17.6 k. J (4.1 kcal) of energy. Proteins are practically not deposited in the reserve. With protein starvation in cells, the proteins of the membranes of the cells themselves are used, which leads to severe metabolic disorders. The daily requirement of an adult for proteins is 90-150 grams (depending on physical activity).

Excess protein in food can be converted to glycogen and fat, but in general, excess amino acids are oxidized to carbon dioxide, water, and ammonia. Ammonia is toxic, so it is converted to non-toxic urea in the liver and excreted in the urine. In the body of an adult, the amount of synthesized proteins is normally equal to the amount of decaying protein. In children, protein synthesis predominates over their breakdown, and in old people, the process of breakdown predominates over synthesis.

In adulthood, a healthy person has a nitrogen balance, i.e. the amount of nitrogen obtained from food proteins is equal to the amount of nitrogen excreted. In a young, growing body, protein mass is accumulated, so the nitrogen balance will be positive, i.e. the amount of incoming nitrogen exceeds the amount excreted from the body. In old age, due to the predominant breakdown of proteins, the nitrogen balance is negative, that is, the amount of nitrogen entering the body is less than the amount of nitrogen excreted from the body.

Diseases associated with lack of protein. The content of protein in the blood serum decreases, hypoproteinemia develops. Following blood proteins, the proteins of the liver, muscles, and skin break down. Later, the proteins of the muscles of the heart and brain break down. An early indicator is a change in urea in the urine.

Carbohydrate metabolism Carbohydrates enter the human body as part of food in the form of monosaccharides (glucose, fructose, galactose), disaccharides (sucrose, maltose, lactose) and polysaccharides (starch, glycogen). Up to 60% of human energy metabolism depends on the transformation of carbohydrates. The oxidation of carbohydrates is much faster and easier than the oxidation of fats and proteins. In the human body, carbohydrates perform a number of important functions:

energy (with the complete oxidation of one gram of glucose, 17.6 k. J of energy is released); receptor (form carbohydrate receptors of glycocalyx cells); protective (part of the mucus); storage (in the muscles and liver are deposited in the reserve in the form of glycogen);

In the human digestive tract, polysaccharides and disaccharides are broken down by amylolytic enzymes to glucose and other monosaccharides. In human blood, the glucose content is very constant, from 0.08 to 0.12%. In the body, excess carbohydrates from the blood under the action of the hormone insulin are deposited in the form of glycogen polysaccharide in the liver and muscles. With a lack of insulin, a serious disease develops - diabetes mellitus.

Glycogen stores in the body of an adult are about 400 grams. These reserves are easily mobilized for energy needs: under the action of the hormone glucagon and some enzymes, glycogen is broken down to glucose. Daily human need for carbohydrates 400 - 600 grams. Plant foods are rich in carbohydrates. With a lack of carbohydrates in food, they can be synthesized from fats and proteins. Excess carbohydrates in food are converted into fats during metabolism.

Fat metabolism Fats (lipids) make up 10-20% of body weight. Most human fat molecules are esters of the trihydric alcohol glycerol and higher carboxylic (fatty) acids. Lipids can be solid (fats) or liquid (oils). Fats perform a number of important functions:

structural (fats - phospholipids are the basis of the structure of cell membranes); energy (complete oxidation of 1 g of fat to carbon dioxide and water releases 38.9 k. J (9.3 kcal) of energy); protective (thermal insulation and waterproofing from external influences of low temperature and aggressive aqueous solutions, compressive effects of mechanical pressure on certain parts of the body); depreciation (fat capsules of some internal organs (kidneys, etc.); a source of endogenous water (1 g of fat during oxidation releases 1.1 g of water that can be used by the body for metabolic needs; animals of the steppes and deserts can go without drinking for a long time due to oxidation reserve fat); regulatory (some hormones are derivatives of fats, such as progesterone, androsterone, etc.); are solvents for fat-soluble vitamins.

In the digestive tract, fats are broken down by lipolytic enzymes into glycerol and fatty acids. These substances in the cells of the mucous membrane of the small intestine are converted into human own fats and absorbed into the lymph. Excess fat from food is deposited on the surface of the internal organs and in the subcutaneous adipose tissue. Human fats contain saturated and unsaturated fatty acids. Unsaturated fatty acids are not synthesized in the human body, so they must be obtained from food.

Vegetable oils are a source of unsaturated fatty acids. The daily requirement of an adult for fats is 80-100 g, while about 30% of their amount should be vegetable oils as a source of unsaturated fatty acids. With a lack of fat in food, they can be synthesized from proteins and carbohydrates. Excessive consumption of animal fats contributes to the formation of cholesterol, which is deposited on the inner walls of the arteries and leads to thickening of their walls and contributes to the development of hypertension.

Water and salt metabolism The human body contains about 65% water. A particularly large amount of water contains cells of the nervous tissue (neurons), cells of the spleen and liver - up to 85%. In embryonic cells, the amount of water can be up to 95%, and in old cells its content is reduced to 60%. For every kilogram of body weight of an adult, there are about 700 g of water, with 500 g of intracellular and 200 g of extracellular water. The daily loss of water in the urine, during breathing, through the skin, with feces in an adult is about 2.5 liters, so the daily need for water is equal to this amount.

Replenishment of water losses is carried out at the expense of food intake of liquid. About 300 g of water is formed daily inside the body due to the oxidation of proteins, fats and carbohydrates. Water as a chemical substance has a number of unique physical and chemical properties, on which the functions that it performs in the body are based:

is a universal solvent (all biochemical reactions in cells occur only in a dissolved state); determines the elasticity (turgor) of cells and tissues; is the basis of liquid transport systems (movement of cytoplasm, blood, lymph) and digestive juices; is the basis of the internal environment (blood, lymph; tissue, pleural, cerebrospinal, articular fluid); is a reagent in biochemical reactions; participates in the conservation, distribution and redistribution of heat in the body and in thermoregulation; Without water, a person can live no more than 5 days.

Mineral salts are necessary for the normal course of metabolic processes and the functioning of all organ systems, normal growth and development. Macronutrients, the number of which is tens and hundreds of grams in the body, are sodium, potassium, calcium, phosphorus and magnesium. The human body requires a wide variety of trace elements, the amount of which is calculated in milligrams. As a rule, the need for mineral salts is covered by food products, with the exception of table salt and iodine, which are poor in the waters and soils of some regions, including the territory of the Altai Territory. Each mineral element fulfills its important role and cannot be replaced by any other element.

Functions of some mineral elements in the human body and their daily requirement Name of the element Functions in the body Daily requirement, g Sodium (sodium chloride) Ions are located in the tissue fluid on the outer surface of the cell membrane; provides cell excitability processes 10 - 12 Potassium ions are located on the inner surface of the cell membrane and provide cell excitability processes 2 - 3

Phosphorus Included in the intercellular substance of bone tissue; is a necessary component of phosphorus-containing organic compounds (ATP, DNA, RNA) 1, 5 - 2, 0 Calcium Included in the intercellular substance of bone tissue; ions are involved in the processes of muscle contraction and blood clotting 0.6 - 0.8 Magnesium Included in the intercellular substance of bone tissue; 0.3 Iron Included in hemoglobin and some oxidative enzymes 0.001 - 0.003 Chlorine (sodium chloride) Included in gastric juice (hydrochloric acid) 10 - 12

Sulfur Included in some amino acids 0.8 - 1.0 Iodine Included in thyroid hormones 0.00003 Zinc Included in enzymes that catalyze the formation of insulin and sex hormones Fluorine Included in hard tissues of teeth and bones Bromine Included in nervous tissue , providing the processes of excitation and inhibition Copper Included in some enzymes 0.001 Cobalt Included in the vitamin B 12 molecule, activates the activity of some respiratory enzymes

The cells are constantly carried out metabolism (metabolism) - diverse chemical transformations that ensure their growth, vital activity, constant contact and exchange with the environment. Thanks to metabolism, proteins, fats, carbohydrates and other substances that make up the cell are continuously broken down and synthesized. The reactions that make up these processes occur with the help of special enzymes in a certain cell organoid and are characterized by high organization and orderliness. Due to this, relative constancy of the composition is achieved in cells, the formation, destruction and renewal of cellular structures and intercellular substance.

Metabolism is inextricably linked with the processes of energy conversion. As a result of chemical transformations, the potential energy of chemical bonds is converted into other types of energy used for the synthesis of new compounds, to maintain the structure and function of cells, etc.

Metabolism consists of two interconnected, simultaneously occurring processes in the body - plastic and energy exchanges .

Plastic metabolism (anabolism, assimilation) - the totality of all reactions of biological synthesis. These substances go to the construction of cell organelles and the creation of new cells during division. Plastic exchange is always accompanied by the absorption of energy.

Energy metabolism (catabolism, dissimilation) - a set of reactions for the splitting of complex high-molecular organic substances - proteins, nucleic acids, fats, carbohydrates into simpler, low-molecular ones. In this case, the energy contained in the chemical bonds of large organic molecules is released. The released energy is stored in the form of energy-rich ATP phosphate bonds.

The reactions of plastic and energy exchanges are interconnected and in their unity constitute the metabolism and the transformation of energy in each cell and in the body as a whole.

plastic exchange

The essence of plastic exchange lies in the fact that from simple substances entering the cell from the outside, cell substances are formed. Let us consider this process on the example of the formation of the most important organic compounds of the cell - proteins.

Protein synthesis is a complex, multi-step process involving DNA, mRNA, tRNA, ribosomes, ATP, and a variety of enzymes. The initial stage of protein synthesis is the formation of a polypeptide chain from individual amino acids located in

strictly defined sequence. The main role in determining the order of amino acids, i.e. The primary structure of a protein belongs to DNA molecules. The sequence of amino acids in proteins is determined by the sequence of nucleotides in the DNA molecule. A section of DNA characterized by a specific sequence of nucleotides is called a gene. A gene is a section of DNA, which is an elementary particle of genetic information. Thus, the synthesis of each specific specific protein is determined by the gene. Each amino acid in the polypeptide chain corresponds to a combination of three nucleotides - a triplet, or codon. It is three nucleotides that determine the attachment of one amino acid to the polypeptide chain. For example, a DNA region with an AAC triplet corresponds to the amino acid leucine, a TTT triplet to lysine, and TGA to threonine. This correlation between nucleotides and amino acids is called the genetic code. Proteins contain 20 amino acids and only 4 nucleotides. Only a code consisting of three consecutive bases could ensure the involvement of all 20 amino acids in the structures of protein molecules. In total, there are 64 different triplets in the genetic code, representing possible combinations of four nitrogenous bases in threes, which is more than enough to code for 20 amino acids. Each triplet codes for one amino acid, but most amino acids are coded for by more than one codon. Currently, the DNA code has been completely deciphered. For each amino acid, the composition of its coding triplets has been precisely determined. For example, the amino acid arginine can correspond to such triplets of DNA nucleotides as HCA, HCG, HCT, HCC, TCT, TCC.

Protein synthesis is carried out on ribosomes, and information about the protein structure is encrypted in DNA located in the nucleus. In order for a protein to be synthesized, information about the sequence of amino acids in its primary structure must be delivered to the ribosomes. This process includes two steps: transcription and translation.

Transcription (literally - rewriting) proceeds as a reaction of matrix synthesis. On the DNA chain, as on a matrix, according to the principle of complementarity, an mRNA chain is synthesized, which in its nucleotide sequence exactly copies (complementary) to the DNA polynucleotide chain, and thymine in DNA corresponds to uracil in RNA. Messenger RNA is not a copy of the entire DNA molecule, but only part of it - one gene that carries information about the structure of the protein that needs to be assembled. There are special mechanisms for “recognizing” the starting point of synthesis, choosing a DNA chain from which information is read, as well as mechanisms for completing the process, in which special codons participate. This is how messenger RNA is formed. An mRNA molecule carrying the same information as genes enters the cytoplasm. The movement of RNA through the nuclear membrane into the cytoplasm occurs due to special proteins that form a complex with the RNA molecule.

In the cytoplasm, a ribosome is strung on one end of the mRNA molecule; amino acids in the cytoplasm are activated with the help of enzymes and are attached again with the help of special enzymes to tRNA (a special binding site for this amino acid). Each amino acid has its own tRNA, one of the sections of which (anticodon) is a triplet of nucleotides corresponding to a specific amino acid and complementary to a strictly defined mRNA triplet.

The next stage of biosynthesis begins - broadcast : assembly of polypeptide chains on an mRNA template. As the protein molecule is assembled, the ribosome moves along the mRNA molecule, and it does not move smoothly, but intermittently, triplet by triplet. As the ribosome moves along the mRNA molecule, amino acids corresponding to mRNA triplets are delivered here with the help of tRNA. To each triplet, on which the ribosome stops in its movement along the thread-like mRNA molecule, tRNA is strictly complementary attached. In this case, the amino acid associated with tRNA is at the active center of the ribosome. Here, special ribosome enzymes cleave the amino acid from the tRNA and attach it to the previous amino acid. After the installation of the first amino acid, the ribosome moves one triplet, and the tRNA, leaving the amino acid, migrates to the cytoplasm for the next amino acid. With the help of this mechanism, the protein chain is built up step by step. Amino acids are combined in it in strict accordance with the arrangement of coding triplets in the chain of the mRNA molecule. The further the ribosome has moved along the mRNA, the larger the segment of the protein molecule is "assembled". When the ribosome reaches the opposite end of the mRNA, synthesis is complete. A threadlike protein molecule separates from the ribosome. The mRNA molecule can be used for the synthesis of polypeptides many times, just like the ribosome. One mRNA molecule can contain several ribosomes (polyribosome). Their number is determined by the length of the mRNA.

Protein biosynthesis is a complex multi-stage process, each link of which is catalyzed by certain enzymes and supplied with energy by ATP molecules.

energy exchange

The process opposite to synthesis is dissimilation - a set of splitting reactions. As a result of dissimilation, the energy contained in the chemical bonds of food substances is released. This energy is used by the cell to carry out various work, including assimilation. During the breakdown of nutrients, energy is released in stages with the participation of a number of enzymes. In energy metabolism, three stages are usually distinguished.

The first stage is preparatory . At this stage, complex high-molecular organic compounds are decomposed enzymatically, by hydrolysis, to simpler compounds - the monomers of which they are composed: proteins - to amino acids, carbohydrates - to monosaccharides (glucose), nucleic acids - to nucleotides, etc. At this stage, a small amount of energy is released, which is dissipated in the form of heat.

The second stage is anoxic, or anaerobic. It is also called anaerobic respiration (glycolysis) or fermentation. Glycolysis occurs in animal cells. It is characterized by gradation, the participation of more than a dozen different enzymes and the formation of a large number of intermediate products. For example, in muscles, as a result of anaerobic respiration, a six-carbon glucose molecule breaks down into 2 molecules of pyruvic acid (C3H403), which are then reduced to lactic acid (C3H603). Phosphoric acid and ADP are involved in this process. The overall expression of the process is as follows:

C6H1 206+ 2H3P04+ 2ADP -» 2C3H603+ 2ATP + 2H20.

During the splitting, about 200 kJ of energy is released. Part of this energy (about 80 kJ) is spent on the synthesis of two ATP molecules, due to which 40% of the energy is stored in the form of a chemical bond in the ATP molecule. The remaining 120 kJ of energy (more than 60%) is dissipated as heat. This process is inefficient.

During alcoholic fermentation, from one molecule of glucose, as a result of a multistage process, two molecules of ethyl alcohol, two molecules of CO2

C6H1206+ 2H3P04+ 2ADP -> 2C2H5OH ++ 2C02+ 2ATP + 2H20.

In this process, the energy output (ATP) is the same as in glycolysis. The fermentation process is a source of energy for anaerobic organisms.

The third stage is oxygen, or aerobic respiration, or oxygen splitting. . At this stage of energy metabolism, the subsequent splitting of the organic substances formed at the previous stage occurs by oxidizing them with atmospheric oxygen to simple inorganic substances, which are the final products - CO2 and H20. Oxygen respiration is accompanied by the release of a large amount of energy (about 2600 kJ) and its accumulation in ATP molecules.

In summary form, the aerobic respiration equation looks like this:

2C3H603+ 602+ 36ADP -» 6C02+ 6H20 + 36ATP + 36H20.

Thus, during the oxidation of two molecules of lactic acid, 36 energy-intensive ATP molecules are formed due to the released energy. Consequently, aerobic respiration plays the main role in providing the cell with energy.

Metabolism has long been defined by scientists. What is metabolism? This is a complex of complex chemical reactions that occur in the body of a person or other living being and affect its viability, maintenance of vitality, growth, development and reproduction, as well as protection from the negative effects of the environment. Metabolism is a prerequisite for the normal existence of a living organism.

The regular supply of nutrients to cells, as well as the constant excretion of end products of decay resulting from various chemical processes, is the basis of biochemical and energy metabolism. Biology studies the essence of these phenomena and the result of their impact on a living organism. What is metabolism, what is the impact of the speed of biochemical and energy processes on changes in the shape and structure of the body, nutrition and lifestyle, as well as adaptability to various conditions of human existence? These are all categories of biological research.

The main types of metabolism

Let's take a closer look at the process itself and its definition. What is metabolism? This is a process that promotes the processing of nutrients coming from outside (proteins, fats, carbohydrates, vitamins, water and minerals), as a result of which the human body creates its own proteins, carbohydrates and fats. At the same time, decay products (splitting), in other words, waste products are excreted through the excretory system into the external environment. Biologists have identified several main types of metabolic processes.

These are protein, lipid (fat), carbohydrate, salt and water metabolism. A variety of enzymes that are involved in the conversion of various nutrients are at the same time a necessary component of digestion. They structure our food. In this case, the metabolism of enzymes is regulated in the right direction.

The two most important interrelated stages of the metabolic process

How do biochemical transformations occur within the body? What causes the metabolic rate to fluctuate? In a healthy person, metabolic processes in the body proceed intensively and quickly.

The technology of these chemical reactions includes two parallel, interrelated, continuous stages: dissimilation and assimilation.

Anabolism (assimilation) is a process associated with the formation of the necessary compounds, during the synthesis of which energy is absorbed.

Catabolism (dissimilation) is a process that, on the contrary, promotes the breakdown of various substances and, as a result, the release of energy. Oxygen is considered to be the main catalyst (accelerator) of this oxidative process.

Factors Affecting Basal Metabolism

Giving a definition of what metabolism is, scientists have identified the necessary minimum consumption of nutrients and energy to maintain the vital activity of the body in ideal comfortable conditions, when a person is at rest. The intensity of metabolic processes can be influenced by:

• genetic memory, or heredity;
• age of a person (because the metabolic rate gradually decreases over the years);
• climatic conditions;
• motor activity or its absence;
• human body weight (obese people require more calories to maintain life support).

In search of an answer to the question of what is the basic metabolism, or basal metabolism, physiologists propose to take into account 4 factors: gender, age, height and body weight of a person. On average, the intensity of basal metabolism is 1 kcal per hour per 1 kg of body weight. In men, the basic metabolism per day is approximately equal to 1500-1700 kcal. In women, this figure is approximately 1300-1500 kcal. In children, the metabolism, as a rule, is higher than in adults, but gradually decreases over the years.

Metabolism and energy balance

Each person has an individual indicator of the level of metabolism and energy. The intake of energy from the outside with food and its expenditure on the life support of the body (basic metabolism plus energy expenditure on physical and mental activity) must be balanced. This energy is measured in units of heat - kilocalories. The balance between the amount of incoming energy and the amount of energy consumed provides a normal energy balance.

Regulation of metabolic processes

Under the influence of factors affecting the basic metabolism, and the difference between the intake and expenditure of calories, the intensity of metabolic processes changes. The most important role in the regulation at all levels belongs to the nervous system. Changes can occur directly in the tissues or organs themselves, and also be a consequence of the regulation of the amount and activity of enzymes and hormones.

Thanks to the feedback principle, our body is able to independently regulate the level of metabolism. For example, when a large amount of glucose enters the bloodstream, energy is released, which increases the secretion of insulin. It inhibits the production of glucose from glycogen in the liver, which, in turn, leads to a decrease in its concentration in the blood.

What is a metabolic disorder and what are its causes

With various metabolic disorders, severe, sometimes irreversible consequences can occur. Malfunctions in carbohydrate metabolism can provoke the development of diabetes mellitus, improper lipid metabolism can lead to the accumulation of bad cholesterol, which causes vascular and heart disease. Excess free radicals lead to premature aging and cancer. The reasons for such failures can be both internal and external.

What is a metabolic disorder from the inside? These are diverse genetic problems associated with a hereditary factor (mutation of genes encoding the synthesis of enzymes that cause defects in metabolic processes). Other causes may be diseases of the nervous system, endocrine disorders (dysfunction of the thyroid gland, pituitary gland, adrenal glands).

To external causes, physiologists include violations in the diet (overeating, unbalanced diets, and so on), ignoring the rules of a healthy lifestyle. Finding out what improper metabolism is, it must be remembered: there are both separate causes of its occurrence, and complex ones, when, along with the disease, a person may have dietary disturbances, physical inactivity.

Fat metabolism

Lipid (fat) metabolism deserves a special discussion. Fats in the human body are the richest source of energy. What is lipid metabolism? More energy is released in the process of lipid oxidation than in the processing of carbohydrates and proteins combined. In addition to a large amount of energy, the breakdown of fats forms a lot of moisture, which supports water metabolism.

Body fats are essential nutrients. Separate vitamins dissolve in lipids, they serve as a component of cell membranes, a material for the synthesis of certain hormones and enzymes, and participate in neuromuscular transmission. Adipose tissue performs a heat-insulating and protective function, softens and moisturizes the skin. A sufficient and balanced amount of fat in the diet guarantees proper lipid metabolism, health and excellent appearance.

What is a fast metabolism, or how to gain weight

How often people, dissatisfied with their thinness, complain that food does not suit them. They cannot gain optimal weight due to a fast metabolism. An increased metabolic rate is genetically inherent in people with an ectomorphic body type. They are characterized by a small amount of subcutaneous fat and a slow rate of muscle building. What is a fast metabolism? This is a high rate of metabolic reactions.

People with such a "gift of nature" are rewarded with increased activity, good physical shape and are not subject to the appearance of excess body weight. After 30 years, especially in women, as a result of physical inactivity and malnutrition, thickening of the subcutaneous fat layer can occur in certain parts of the body. This is partly the result of the fact that every six months, starting from this age, the metabolic rate decreases by 3-4%. But correcting the figure in these cases is very simple: you just need to adhere to a balanced diet and increase physical activity.

How to restore the correct metabolism?

Many lovers of rigid unbalanced diets that guarantee rapid weight loss soon find themselves in a dilemma. By continuing to reduce the calorie content of their diet, they get a decrease in the level of metabolism, which leads to the fixation of the arrow of the scales. A calorie deficit no longer leads to weight loss. Nutritionists in this case are advised to increase metabolism. What is a fast metabolism? This is a mandatory morning breakfast, a fractional balanced diet throughout the day, a large amount of water drunk, aerobic and anaerobic training, outdoor walks, visiting saunas and baths, and sleeping for at least 8-9 hours. In addition, it is necessary to include in the diet products that accelerate metabolism: spices (pepper, cinnamon, ginger, mustard), seafood, citrus fruits (grapefruit), ginseng, B vitamins, green tea.

In fact, what is the ideal metabolism? This is a competent ratio of the amount of food consumed and its expenditure. An early breakfast will help the body “wake up” and start the metabolic process, fractional nutrition will provide vital substances without hunger and harm to the body, and physical activity will bring the body to the desired shape. Hunger, on the contrary, slows down and stops the metabolism, which leads to the cessation of the weight loss process.

Conclusion

Prevention of metabolic disorders consists not only in regular visits to the doctor, but also in a healthy diet, a competent work regime and sufficient rest, compliance with environmental and sanitary standards (as far as possible), physical activity. Knowing what metabolism is, you can ensure the perfect functioning of your body and stay healthy for many years!

Metabolism or metabolism- this is a complete complex of chemical reactions and processes that occur in a living cell, ensuring its vital activity, growth, division and interaction with the external environment.

Exactly right metabolism ensures the breakdown and assimilation of molecules of substances that make up cells or are necessary for the functioning, destruction, renewal of cells and intercellular substance. Thanks to proper metabolism, the tissue cover of the body is updated in 80 days, muscle fiber proteins are updated in 180 days, liver cells and blood serum are updated in 10 days, and some liver enzymes are renewed in just 2-4 hours.

Metabolism inextricably linked to the process energy conversion. As a result of chemical reactions, potential energy from complex organic molecules is converted into other types of energy, which is used for all life processes of cells. All these processes proceed with the participation of catalysts - enzymes. For each species of living organisms, the metabolism is unique, peculiar only to this species. The metabolism of each species is determined primarily by the conditions of its habitat and existence in general.

The metabolism consists of two main processes, which are inextricably linked with each other and proceed simultaneously:

• Anabolism (assimilation);
• Catabolism (dissimilation).

Anabolism ( plastic exchange) are the processes of synthesis (construction) of complex organic molecules from simpler ones obtained as a result of catabolism.

Catabolic processes are a complex of chemical reactions for the breakdown of large molecules into smaller ones that could pass into the cell. At the same time, energy is released, which organisms usually store in ATP molecules ( adenosine triphosphate). Catabolism usually occurs during oxidative or hydrolytic reactions. At the same time, such processes proceed both with the participation of oxygen ( breath, aerobic pathway), and without its participation (fermentation, glycolysis - anaerobic pathway).

Depending on the type of metabolism, there is two types of living organisms:

1) Heterotrophs- these are organisms that synthesize organic compounds due to the products that are formed as a result of catabolism and the energy released in the process. The initial raw materials for the formation of tissues of such organisms are simple organic substances. From these compounds, each cell individually synthesizes the compounds it needs. Thus, protein synthesis can occur locally (glycogen is synthesized directly in the muscles, and not supplied with blood from the liver).

2) Autotrophs- these are organisms that can synthesize organic compounds from carbon dioxide using oxidation reactions ( chemosynthesis) and sunlight ( photosynthesis). Such organisms are some types of bacteria and green plants.

With the development of living organisms during evolution, the regulatory systems have become more complex and ordered. Today, highly developed organisms have additional regulatory hormonal mechanisms and neural mechanisms, which either directly act on the synthesis of enzymes or on the enzymes themselves, and can also affect the sensitivity of cells to a particular enzyme.

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The term "metabolism" (metabolism) in Greek means "change" or "transformation". So what is being transformed?

Metabolism- this is a combination of all biochemical and energy processes in the body, during which the incoming food, water, air are converted into energy and a number of substances necessary to maintain life. This function allows our body to use food and other resources to maintain its structure, repair damage, get rid of toxins, and reproduce. In other words, metabolism is a necessary process without which living organisms will die.

Metabolic functions:

1. maintaining the constancy of the internal environment of the body in continuously changing conditions of existence and adaptation to changes in external conditions.
2. ensuring life, development and self-reproduction.

Metabolism begins with the absorption of nutrients needed to sustain life. But we absorb other people's proteins, fats and carbohydrates! And you have to build your own. What do I need to do? Correctly! Break down the incoming complex substances into simpler components, and then build individual proteins, fats and carbohydrates from them. That is, you must first disassemble, and then build.

Therefore, the entire metabolic process can be divided into 2 closely related components, two parts of one process - metabolism.

1. Catabolism- These are such processes in the body that are aimed at splitting food, as well as their own molecules, into simpler substances, while releasing energy and storing it in the form of adenosine triphosphate (ATP).
The first stage of catabolism is the process of digestion, during which proteins are broken down into amino acids, carbohydrates into glucose, lipids into glycerol and fatty acids. Then, already in the cells, these molecules are converted into even smaller ones, for example, fatty acids - into acetyl-CoA, glucose - into pyruvate, amino acids - into oxaloacetate, fumarate and succinate, etc. The main end products of catabolism are water, carbon dioxide, ammonia, and urea.

The destruction of complex substances is necessary for the urgent needs of obtaining energy and building new tissues. Without the processes of catabolism, the body would be left without energy, which means it could not exist. After all, this energy will subsequently be directed to the synthesis of necessary substances, the creation of tissues and the renewal of the body, that is, to anabolism. Energy is also needed for muscle contraction, transmission of nerve impulses, maintaining body temperature, etc.

2. Anabolism- these are metabolic processes in the body that are aimed at the formation of cells and tissues of this organism. Many substances obtained as a result of catabolism are subsequently used by the body for the synthesis (anabolism) of other substances.
Anabolic processes always proceed with the absorption of ATP energy. In the course of anabolic metabolism, larger molecules are structured from smaller molecules, and more complex ones are formed from simpler structures.
Thus, as a result of catabolism and subsequent anabolism, proteins, fats and carbohydrates characteristic of this organism are built from the nutrients entering the body.

Table 1 Comparison of anabolism and catabolism.

Despite the opposite of anabolism and catabolism, they are inextricably linked and cannot proceed without each other.
The totality of the processes of anabolism and catabolism is the metabolism, or metabolism.
The balance of these two components is regulated by hormones and makes the body work smoothly. Enzymes while playing the role of catalysts in metabolic processes.

How is metabolic rate measured? What metabolic rate?

Measuring the level of metabolism, of course, no one counts the number of newly formed or destroyed cells or tissues.
The metabolic rate is measured by the amount of energy absorbed and released. We are talking about the energy that enters the body with food, and the one that a person spends in the process of life. It is measured in calories.
Calories are to the body like gasoline is to a car. It is a source of energy thanks to which the heart beats, muscles contract, the brain functions, and a person breathes.

When they say "increased or decreased metabolism", they mean an increased or decreased rate (or intensity) of metabolism.

metabolic rate is the amount of energy consumed by the body in calories over a period of time.

How many calories does a healthy person burn per day?
The energy that a person spends in the process of life includes 3 components:
1) The energy that is spent on the main metabolism (this is the main indicator of metabolism) +
2) The energy spent on the assimilation of food - the specific dynamic action of food (SDAP) +
3) The energy that is spent on physical activity.

But when it comes to individual increased or decreased metabolism, it is the main metabolism that is meant.

Basic exchange - what is it?

BX- this is the minimum amount of energy that the body needs to maintain its normal functioning in conditions of complete rest 12 hours after eating in the waking state and with the exclusion of the influence of all external and internal factors.
This energy is spent on maintaining body temperature, blood circulation, respiration, excretion, the functioning of the endocrine system, the functioning of the nervous system, and the processes of cellular metabolism.
Basal metabolism shows how intensively the metabolism and energy in the body proceeds.
The main metabolism depends on gender, weight, age, the state of internal organs, the influence of external factors on the body (lack or excess of nutrition, intensity of physical activity, climate, etc.)
Basal metabolism can increase or decrease under the influence of external or internal factors. So lowering the outside temperature increases basal metabolism. An increase in outside temperature reduces basal metabolic rate.

Why is it important to know basal metabolism?

Because basal metabolism is an indicator of the intensity of metabolism and energy in the body, then its changes may indicate the presence of certain diseases.
For this, the "due basal exchange" is compared with the "actual basal exchange".

Due basic exchange- This is an average indicator that was established on the basis of the results of a survey of a large number of healthy people. It is considered to be the norm.
Based on these results, special tables have been compiled, which indicate the proper basal metabolism, taking into account gender, age and weight.
The proper basal exchange is taken as 100%. It is measured in kcal per 24 hours.
The proper basal metabolic rate for a healthy adult is approximately 1 kcal per 1 kg of body weight per hour.

Actual basal exchange is the individual basal exchange of the individual. It is expressed as a percentage deviation from the due. If a actual basal exchange increased - with a plus sign, if lowered - with a minus sign.

A deviation from the due value by +15 or -15% is considered acceptable.
Deviations from +15% to +30% are considered doubtful and require monitoring and control.
Deviations from +30% to +50% are considered moderate deviations, from +50% to +70% - severe, and more than +70% - very severe.
A decrease in basal metabolic rate of 30-40% is also considered to be associated with a disease that requires treatment for that disease.

Actual basal exchange determined by calorimetry in special laboratories.