Metabolism (metabolism)- this is the totality of all chemical reactions that occur in the body. All these reactions are divided into 2 groups

1. Plastic exchange(assimilation, anabolism, biosynthesis) - this is when from simple substances with energy consumption are formed (synthesized) more complex. Example:

• During photosynthesis, glucose is synthesized from carbon dioxide and water.

2. Energy metabolism(dissimilation, catabolism, respiration) - this is when complex substances disintegrate (oxidize) to simpler ones, and at the same time energy is released, necessary for life. Example:

• In mitochondria, glucose, amino acids and fatty acids are oxidized by oxygen to carbon dioxide and water, which produces energy (cellular respiration)

The relationship between plastic and energy metabolism

• Plastic metabolism provides the cell with complex organic substances (proteins, fats, carbohydrates, nucleic acids), including enzyme proteins for energy metabolism.
• Energy metabolism provides the cell with energy. When performing work (mental, muscular, etc.), energy metabolism increases.

ATP– universal energy substance of the cell (universal energy accumulator). It is formed in the process of energy metabolism (oxidation of organic substances).

• During energy metabolism, all substances break down, and ATP is synthesized. In this case, the energy of the chemical bonds of the disintegrated complex substances is converted into the energy of ATP, energy is stored in ATP.
• During plastic metabolism, all substances are synthesized, and ATP breaks down. Wherein ATP energy is consumed(ATP energy is converted into the energy of chemical bonds of complex substances and is stored in these substances).

Choose one, the most correct option. During the process of plastic exchange
1) more complex carbohydrates are synthesized from less complex ones
2) fats are converted into glycerol and fatty acids
3) proteins are oxidized to form carbon dioxide, water, and nitrogen-containing substances
4) energy is released and ATP is synthesized

Answer

Choose one, the most correct option. In the process of plastic metabolism, molecules are synthesized in cells
1) proteins
2) water
3) ATP
4) inorganic substances

Answer

Choose one, the most correct option. The nitrogenous base adenine, ribose and three phosphoric acid residues are included in the composition
1) DNA
2) RNA
3) ATP
4) squirrel

Answer

Choose one, the most correct option. What is the relationship between plastic and energy metabolism?
1) plastic metabolism supplies organic substances for energy
2) energy metabolism supplies oxygen for plastic
3) plastic metabolism supplies minerals for energy
4) plastic metabolism supplies ATP molecules for energy

Answer

Choose one, the most correct option. In the process of energy metabolism, in contrast to plastic, there is
1) consumption of energy contained in ATP molecules
2) energy storage in high-energy bonds of ATP molecules
3) providing cells with proteins and lipids
4) providing cells with carbohydrates and nucleic acids

Answer

Choose one, the most correct option. The energy required for muscle contraction is released when
1) the breakdown of organic substances in the digestive organs
2) irritation of the muscle by nerve impulses
3) oxidation of organic substances in muscles
4) ATP synthesis

Answer

Choose one, the most correct option. As a result of what process are lipids synthesized in a cell?
1) dissimilation
2) biological oxidation
3) plastic exchange
4) glycolysis

Answer

Choose one, the most correct option. The meaning of plastic metabolism is the supply of the body
1) mineral salts
2) oxygen
3) biopolymers
4) energy

Answer

Choose one, the most correct option. Oxidation of organic substances in the human body occurs in
1) pulmonary bubbles during breathing
2) body cells in the process of plastic metabolism
3) the process of digesting food in the digestive tract
4) body cells in the process of energy metabolism

Answer

Choose one, the most correct option. What metabolic reactions in a cell are accompanied by energy expenditure?
1) preparatory stage of energy metabolism
2) lactic fermentation
3) oxidation of organic substances
4) plastic exchange

Answer

PLASTIC EXCEPT
1. All but two of the following terms are used to describe plastic exchange. Identify two terms that "fall out" from the general list, and write down the numbers under which they are indicated.
1) replication
2) duplication
3) broadcast
4) translocation
5) transcription

Answer

2. All of the concepts listed below, except two, are used to describe plastic metabolism in a cell. Identify two concepts that “fall out” from the general list and write down the numbers under which they are indicated.
1) assimilation
2) dissimilation
3) glycolysis
4) transcription
5) broadcast

Answer

3. The terms listed below, except two, are used to characterize plastic exchange. Identify two terms that are missing from the general list and write down the numbers under which they are indicated.
1) splitting
2) oxidation
3) replication
4) transcription
5) chemosynthesis

Answer

ENERGY
Select three processes related to energy metabolism.
1) release of oxygen into the atmosphere
2) formation of carbon dioxide, water, urea
3) oxidative phosphorylation
4) glucose synthesis
5) glycolysis
6) photolysis of water

Answer

ENERGY EXCEPT
All of the signs below, except two, can be used to characterize energy metabolism in a cell. Identify two characteristics that “drop out” from the general list, and write down the numbers under which they are indicated in your answer.
1) comes with energy absorption
2) ends in mitochondria
3) ends in ribosomes
4) accompanied by the synthesis of ATP molecules
5) ends with the formation of carbon dioxide

Answer

PLASTIC - ENERGY
1. Establish a correspondence between the characteristics of exchange and its type: 1) plastic, 2) energetic. Write the numbers 1 and 2 in the correct order.
A) oxidation of organic substances
B) formation of polymers from monomers
B) ATP breakdown
D) energy storage in the cell
D) DNA replication
E) oxidative phosphorylation

Answer

2. Establish a correspondence between the characteristics of metabolism in a cell and its type: 1) energy, 2) plastic. Write numbers 1 and 2 in the order corresponding to the letters.
A) oxygen-free breakdown of glucose occurs
B) occurs on ribosomes, in chloroplasts
B) end products of metabolism - carbon dioxide and water
D) organic substances are synthesized
D) the energy contained in ATP molecules is used
E) energy is released and stored in ATP molecules

Answer

3. Establish a correspondence between the signs of human metabolism and its types: 1) plastic metabolism, 2) energy metabolism. Write the numbers 1 and 2 in the correct order.
A) substances are oxidized
B) substances are synthesized
B) energy is stored in ATP molecules
D) energy is consumed
D) ribosomes are involved in the process
E) mitochondria are involved in the process

Answer

4. Establish a correspondence between the characteristics of metabolism and its type: 1) energetic, 2) plastic. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) DNA replication
B) protein biosynthesis
B) oxidation of organic substances
D) transcription
D) ATP synthesis
E) chemosynthesis

Answer

5. Establish a correspondence between the characteristics and types of exchange: 1) plastic, 2) energy. Write down the numbers 1 and 2 in the order corresponding to the letters.
A) energy is stored in ATP molecules
B) biopolymers are synthesized
B) carbon dioxide and water are formed
D) oxidative phosphorylation occurs
D) DNA replication occurs

Answer

COLLECTING 6:
A) fats are formed from fatty acids and glycerol
B) proteins are synthesized from amino acids
B) energy is released
D) glycogen is formed from glucose

A) protein is broken down into amino acids

PLASTIC - ENERGY FOREIGN
1. Establish a correspondence between the processes and components of metabolism: 1) anabolism (assimilation), 2) catabolism (dissimilation). Write the numbers 1 and 2 in the correct order.
A) fermentation
B) glycolysis
B) breathing
D) protein synthesis
D) photosynthesis
E) chemosynthesis

Answer

2. Establish a correspondence between the characteristics and metabolic processes: 1) assimilation (anabolism), 2) dissimilation (catabolism). Write down the numbers 1 and 2 in the order corresponding to the letters.
A) synthesis of organic substances in the body
B) includes the preparatory stage, glycolysis and oxidative phosphorylation
C) the released energy is stored in ATP
D) water and carbon dioxide are formed
D) requires energy expenditure
E) occurs in chloroplasts and on ribosomes

Answer

PLASTIC - ENERGY DIFFERENCES
Choose three options. How does plastic metabolism differ from energy metabolism?
1) energy is stored in ATP molecules
2) the energy stored in ATP molecules is consumed
3) organic substances are synthesized
4) organic substances are broken down
5) end products of metabolism - carbon dioxide and water
6) as a result of exchange reactions, proteins are formed

Answer

METABOLISM
Choose two correct answers from five and write down the numbers under which they are indicated. Metabolism is one of the main properties of living systems; it is characterized by what happens
1) selective response to external environmental influences
2) changes in the intensity of physiological processes and functions with different periods of oscillation
3) transmission from generation to generation of traits and properties
4) absorption of necessary substances and release of waste products
5) maintaining a relatively constant physical and chemical composition of the internal environment

Answer

© D.V. Pozdnyakov, 2009-2019

Line UMK S. A. Titov. Science (10-11) (basic)

natural science

Biology

Stages of energy metabolism

How does a living organism work, what is the essence of energy metabolism? Let's find out what synthesis is, catabolism, and which scientists simultaneously discovered the ATP molecule. And for the most attentive, there is a test at the end of the article.

A living organism is made up of cells. And some, for example, amoeba or ciliates, consist of one cell. Complex multicellular individuals are represented by combinations of cells that form various systems of the body: or the digestive system. The entire body is permeated with nervous tissue cells that provide regulation and control of the macroorganism.

A living cell differs from a non-living one in that two multidirectional processes constantly and continuously occur in it:

• synthesis, or construction of new organelles (plastic exchange or assimilation)
• catabolism, or the breakdown of nutrients to produce energy (energy metabolism or dissimilation)

In living individuals, the balance between assimilation and dissimilation is not always maintained. If you observe the life of an organism, you will notice that at first the body becomes larger in size, stronger and more resilient. The older the body becomes, the less noticeable growth is, and in old age decay processes begin to predominate, the body does not have time to recover and dies.

For a car to move, it needs gasoline. And gasoline is made from oil. For a macroorganism to exist, it needs energy. In biology textbooks you can often find the phrase glucose - an energy resource for the cell. This is true. But glucose is like oil for a car. Therefore, glucose must first be converted into gasoline. And the ATP molecule will be such gasoline for the cell.

In 1929, almost simultaneously, Karl Lohmann and Otto Meyerhof from the Kaiser Wilhelm Institute of Biology in Berlin and Harvard Medical School scientists Cyrus Fiske and Yellapragad Subbarao at Harvard Medical School published papers in which they described the ATP molecule.

In the 30s of the twentieth century, a young scientist, Fritz Lipmann, appeared in Meyerhof’s laboratory, who became interested in the energy aspects of cellular metabolism, and in 1941, the talented biochemist proved that ATP is the main engine of energy reactions in a living cell. And in 1953, his contribution to physiology, together with H. Krebs, was awarded the Nobel Prize.

ATP - adenosine triphosphate, a nucleotide, a global energy resource for complex metabolic reactions occurring in the body's cells. The ATP molecule is shown schematically in

The whole essence of energy metabolism comes down to solving the problem of how to convert energy from complex food molecules into an ATP molecule. In the process of evolution, this problem was solved.

So how does a McDonald's bun turn into ATP energy?

In energy metabolism, several processes are distinguished, separated not only by time, but also occurring in different parts of the cell:

• Preparatory stage
• Glycolysis
• Oxygen oxidation

The preparatory stage in humans and other multicellular macroorganisms begins in the oral cavity, continues in the gastrointestinal tract and is a multi-stage process of decomposition of complex polymers of proteins, fats and carbohydrates of food into monomers.

We remember from the chemistry course that when the bonds of elements are broken, energy is released. This energy is not enough for the formation of adenosine triphosphate, and it all goes into the external environment.

What happens in simple single-celled organisms that do not have mouths or bellies? Food captured by a single-celled organism enters the digestive vacuole or lysosome, where the initial stage of dissimilation occurs with the help of catalytic enzymes that promote digestion.

The substances prepared during the preliminary stage pass into the second oxygen-free stage of energy metabolism, which is called glycolysis.

Two Greek words ( glycos– “sweet” and lysis- “split”) gave the name to the second oxygen-free phase of energy metabolism - glycolysis.

Glycolysis is a chain of 10 biochemical transformations, the result of which is the transformation of a stable glucose molecule into three-carbon molecules pyruvate, - or pyruvic acid.

“Wait,” meticulous students might say, “glucose is in our digestive system. And metabolic processes occur in cells throughout the body, for example, on the tip of the nose or the hind paw. How does glucose get into the cytoplasm of cells throughout the body?”

Glucose is absorbed in the gastrointestinal tract, enters the bloodstream, is carried by the bloodstream to all tissues and cells of the body, and thanks to the insulin carrier protein, enters the cell.

The cytoplasm of an individual cell is the site of glycolysis reactions. In this case, very little energy is released. It is only enough to form 2 ATP molecules. It would seem that the energy has been received and the process can stop. This is what happens in some bacteria. But no normal multicellular organism will have enough ATP reserves. There is still a sufficient supply of energy left in pyruvic acid, which the macroorganism would also like to use.

The textbook is distinguished by its high-quality, modern design and contains numerous slides and microphotographs. By completing problem-solving, search and research tasks, schoolchildren not only actively absorb the material, but also learn to think, search and analyze information from various sources, including the Internet. Particular attention is paid to practical tasks: students are encouraged to conduct experiments, construct models, and develop projects.

In multicellular bodies, pyruvate enters the third phase of dissimilation - cellular respiration in mitochondria. The process is called respiration because during chemical reactions in mitochondria, oxygen is consumed and carbon dioxide is released into the cytoplasm of the cell, and then, with the help of blood circulation and respiration, into the external environment.

Cellular respiration is represented by two stages:

• Krebs cycle, which occurs in the mitochondrial matrix
• oxidative phosphorylation occurring on mitochondrial cristae with the participation of respiratory chain enzymes

The result of the oxygen stage of energy metabolism is the release of an amount of energy sufficient to form 36 molecules of ATP, water and CO2. It must be remembered that adenosine triphosphate contains three phosphate residues, and only two high-energy bonds are formed. The overall equation of the biochemical reactions occurring in the third phase of dissimilation can be written as follows:

2C 3 H 4 O 3 +6O 2 +36H 3 PO 4 +36ADP=6CO 2 +42H 2 O+36ATP

As a result of these reactions, a huge amount of energy is accumulated - 36 molecules of adenosine triphosphate versus 2 that are stored during glycolysis. However, since this phase requires oxygen for its reactions, the process cannot proceed in an oxygen-free environment.

When there is a lack of oxygen, pyruvate is oxidized to lactate. It is he who owns the feeling of pleasant pain after a good workout. In well-trained people with an active blood supply and a well-developed network of capillaries, a lot of physical activity must be done before lactic acid begins to accumulate.

Let us remember that 2 more molecules of adenosine triphosphate accumulate at the stage of glycolysis. Thus, the breakdown of one glucose molecule produces 38 ATP molecules.

On the LECTA portal In paragraph 22, attentive students will find the answer to the question why potassium cyanide is the favorite drug of murderers in detective novels.

Metabolism (metabolism) consists of the processes of splitting and synthesis - dissimilation and assimilation, constantly occurring in the body. For life to continue, the amount of energy in must exceed (or at least equal) the amount of energy expended, so dissimilation and assimilation maintain a certain balance with each other.

Energy exchange

Energy metabolism (dissimilation - from the Latin dissimilis - dissimilar) is the opposite side of assimilation of metabolism, a set of reactions that lead to the release of the energy of chemical bonds. These are reactions that break down fats, proteins, carbohydrates, and nucleic acids into simple substances.

There are three possible stages of dissimilation: preparatory, anaerobic and aerobic. The habitat determines the number of stages of dissimilation. There can be three of them if the organism lives in an oxygen environment, and two if we are talking about an organism living in an oxygen-free environment (for example, in the intestines).

Let's discuss the stages of energy metabolism in more detail:

ATP - adenosine triphosphoric acid

It is difficult to overestimate the role of ATP, a universal source of energy, in the cell. The ATP molecule consists of a nitrogenous base - adenine, a carbohydrate - ribose and three phosphoric acid residues.

Between the phosphoric acid residues there are high-energy bonds - covalent bonds that hydrolyze releasing a large amount of energy. They are usually denoted by the typographical tilde "∽".

ATP is hydrolyzed to ADP (adenosine diphosphoric acid), and then to AMP (adenosine monophosphoric acid). ATP hydrolysis is accompanied by the release of energy (E) at each stage and can be represented by the following diagram:

• ATP + H 2 O = ADP + H 3 PO 4 + E
• ADP + H 2 O = AMP + H 3 PO 4 + E
• AMP + H 2 O = adenine + ribose + H 3 PO 4 + E

Plastic exchange

ATP is a universal source of energy in the cell: the energy of macroergic bonds of ATP is used for plastic exchange reactions (assimilation) that occur with energy consumption: protein synthesis on the ribosome (translation), DNA doubling (replication), etc.

As a result of plastic metabolism, the synthesis of proteins, fats and carbohydrates occurs in our body.

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All food substances have a certain amount of energy.

The body is called an energy transformer, since specific transformations of nutrients constantly occur in it,

leading to the release of energy and its transition from one type to another. The relationship between the amount of energy received from food and the amount of energy expended is called energy balance body. To study it, it is necessary to determine the energy value of food.

The energy value of nutrients does not always coincide with their physiological value, since the latter is determined by their ability to assimilate. Nutrients of animal origin are absorbed better than those of plant origin.

Methods for determining energy metabolism. The amount of energy released in the body depends on the chemical transformations of substances in it, i.e. from metabolic processes. It follows that the amount of heat released by the body can serve as an indicator of metabolism. Determining the amount of heat (number of calories) released by the body gives the entire amount of energy transformations in the form of the final thermal total. This method of determining energy is called direct calorimetry. Determination of the number of calories by direct calorimetry is carried out using a calorimetric chamber, or calorimeter. However, this method of determining energy balance is labor-intensive.

All these determinations can be made much easier by studying gas exchange. Determining the amount of energy released by the body by studying gas exchange is called indirect calorimetry. Knowing that the entire amount of energy released in the body is the result of the breakdown of proteins, fats and carbohydrates; Knowing also how much energy is released during the decay of these substances and how much of them has undergone decay over a certain period of time, we can calculate the amount of energy released. In order to determine which substances have undergone oxidation in the body - proteins, fats or carbohydrates, calculate respiratory quotient, i.e. the ratio of the volume of carbon dioxide released to the volume of oxygen absorbed. The respiratory coefficient is different during the oxidation of proteins, fats and carbohydrates. For example, let’s consider what the respiratory coefficient will be during the oxidation of glucose. Summary formula for glucose breakdown

During the oxidation of glucose, the number of molecules of CO2 formed is equal to the number of molecules of absorbed 02. An equal number of gas molecules at the same temperature and the same pressure occupy the same volume (Avogadro's law). Consequently, the respiratory coefficient (ratio C0 2 / 0 2) during the oxidation of glucose and other carbohydrates is equal to one.

During the oxidation of fats and proteins, the respiratory coefficient will be below unity. During fat oxidation, the respiratory coefficient is 0.7. Let us illustrate this using the example of tripalmitin oxidation:

The ratio between the volumes of carbon dioxide and oxygen is in this case 102C02/14502 = 0.703.

A similar calculation can be made for protein; when it is oxidized in the body, the respiratory coefficient is 0.8. With mixed food, a person's respiratory quotient is usually 0.85-0.89.

Knowing the value of the respiratory coefficient, using the tables you can determine thermal equivalent of oxygen, those. the amount of energy released for each liter of oxygen consumed. The thermal equivalent of oxygen is not the same at different values ​​of the respiratory coefficient. To determine the amount of oxygen consumed and carbon dioxide released, the Douglas-Haldane method is used. The subject takes the mouthpiece into his mouth, closes his nose, and all the air exhaled over a certain period of time is collected in a rubber bag. The volume of exhaled air is determined using a gas clock. An air sample is taken from the bag and the oxygen and carbon dioxide content in it is determined; the inhaled air contains a certain amount of them. The difference in percentage is used to calculate the amount of oxygen consumed, carbon dioxide released and the respiratory coefficient. Then the thermal equivalent of oxygen corresponding to its value is found, which is multiplied by the number of liters of oxygen consumed. In this case, the exchange value is obtained for the period of time during which the gas exchange was determined. Then this value is converted into days.

Basic and general metabolism. A distinction is made between general metabolism and metabolism at complete rest, which is called main It is determined under the following conditions:

• in a state of muscular rest (lying position with relaxed muscles), in the absence of irritations that cause emotional stress;
• on an empty stomach, i.e. 12-16 hours after eating;
• at an external temperature of “comfort” (21-22 ° C), which does not cause feelings of cold and heat.

The subject is put to bed and after 30 minutes the determination of gas exchange begins. Under these conditions, energy is spent on heart function, breathing, maintaining body temperature, etc. But these costs are small. The main costs in determining basal metabolism are associated with chemical processes that always take place in cells. The basal metabolic rate is 4200-8400 kJ per day in men and 4200-7140 kJ in women.

Metabolism can vary significantly under different conditions. For example, the basal metabolic rate during sleep decreases by 8-10% compared to the study during wakefulness. During work, with muscle load, on the contrary, it increases significantly. The more intense the muscle load, the more significant the increase in volume. In this regard, workers of various professions spend unequal amounts of energy per day: from 2500 kcal/day (workers predominantly in mental labor) to 4500 kcal/day (workers of particularly heavy physical labor).

Mental work causes an increase in metabolism by only 2-3%. Any emotional excitement inevitably leads to an increase in metabolism. After eating, metabolism increases by 10-40%. The effect of food on metabolism does not depend on the activity of the gastrointestinal tract; it is due to the specific effect of food on metabolism. In this regard, it is customary to talk about the specific dynamic effect of food on metabolism, meaning by this its increase after eating.

Regulation of energy metabolism. The level of energy metabolism directly depends on physical activity, emotional stress, the nature of nutrition, the degree of thermoregulation stress and a number of other factors.

Numerous data indicate a conditioned reflex change in oxygen consumption and energy metabolism. Any previously indifferent stimulus associated in time with muscle activity can serve as a signal to increase metabolism and energy. Thus, an athlete in the pre-start state sharply increases oxygen consumption, and therefore energy exchange. The hypothalamic region of the brain plays a special role in energy exchange. Here regulatory influences are formed, which are realized by the autonomic nerves or the humoral component by increasing the secretion of a number of hormones. The thyroid hormones, thyroxine and triiodothyronine, and the adrenal medulla hormones, adrenaline and norepinephrine, especially enhance energy metabolism.