ATP synthesis occurs in. ATP molecule in biology: composition, functions and role in the body. The structure of the ATP molecule

Adenosine triphosphoric acid-ATP- an obligatory energy component of any living cell. ATP is also a nucleotide consisting of the nitrogenous base of adenine, the sugar of ribose, and three residues of the phosphoric acid molecule. This is an unstable structure. In metabolic processes, phosphoric acid residues are sequentially split off from it by breaking the energy-rich, but fragile bond between the second and third phosphoric acid residues. The detachment of one molecule of phosphoric acid is accompanied by the release of about 40 kJ of energy. In this case, ATP passes into adenosine diphosphoric acid (ADP), and with further cleavage of the phosphoric acid residue from ADP, adenosine monophosphoric acid (AMP) is formed.

Schematic diagram of the structure of ATP and its transformation into ADP ( T.A. Kozlova, V.S. Kuchmenko. Biology in tables. M., 2000 )

Consequently, ATP is a kind of energy accumulator in the cell, which is "discharged" when it is split. The breakdown of ATP occurs during the reactions of synthesis of proteins, fats, carbohydrates and any other vital functions of cells. These reactions go with the absorption of energy, which is extracted during the breakdown of substances.

ATP is synthesized in mitochondria in several stages. The first one is preparatory - proceeds stepwise, with the involvement of specific enzymes at each step. In this case, complex organic compounds are broken down to monomers: proteins - to amino acids, carbohydrates - to glucose, nucleic acids - to nucleotides, etc. Breaking bonds in these substances is accompanied by the release of a small amount of energy. The resulting monomers under the action of other enzymes can undergo further decomposition with the formation of simpler substances up to carbon dioxide and water.

Scheme Synthesis of ATP in the mitochondria of the cell

EXPLANATIONS TO THE SCHEME CONVERSION OF SUBSTANCES AND ENERGY IN THE PROCESS OF DISSIMILATION

Stage I - preparatory: complex organic substances under the action of digestive enzymes break down into simple ones, while only thermal energy is released.
Proteins -> amino acids
Fats- > glycerin and fatty acids
Starch ->glucose

Stage II - glycolysis (oxygen-free): carried out in the hyaloplasm, not associated with membranes; it involves enzymes; glucose is broken down:

In yeast fungi, the glucose molecule, without the participation of oxygen, is converted into ethyl alcohol and carbon dioxide (alcoholic fermentation):

In other microorganisms, glycolysis can be completed with the formation of acetone, acetic acid, etc. In all cases, the breakdown of one glucose molecule is accompanied by the formation of two ATP molecules. During the oxygen-free breakdown of glucose in the form of a chemical bond, 40% of the anergy is retained in the ATP molecule, and the rest is dissipated in the form of heat.

Stage III - hydrolysis (oxygen): carried out in mitochondria, associated with the mitochondrial matrix and the inner membrane, enzymes participate in it, lactic acid undergoes cleavage: C3H6Oz + 3H20 --> 3CO2 + 12H. CO2 (carbon dioxide) is released from the mitochondria into the environment. The hydrogen atom is included in a chain of reactions, the end result of which is the synthesis of ATP. These reactions go in the following order:

1. The hydrogen atom H, with the help of carrier enzymes, enters the inner membrane of mitochondria, which forms cristae, where it is oxidized: H-e--> H+

2. Hydrogen proton H+(cation) is carried by carriers to the outer surface of the membrane of the cristae. For protons, this membrane is impermeable, so they accumulate in the intermembrane space, forming a proton reservoir.

3. Hydrogen electrons e are transferred to the inner surface of the cristae membrane and immediately attach to oxygen with the help of the oxidase enzyme, forming a negatively charged active oxygen (anion): O2 + e--> O2-

4. Cations and anions on both sides of the membrane create an oppositely charged electric field, and when the potential difference reaches 200 mV, the proton channel begins to operate. It occurs in the enzyme molecules of ATP synthetase, which are embedded in the inner membrane that forms the cristae.

5. Hydrogen protons through the proton channel H+ rush inside the mitochondria, creating a high level of energy, most of which goes to the synthesis of ATP from ADP and P (ADP + P -\u003e ATP), and protons H+ interact with active oxygen, forming water and molecular 02:
(4Н++202- -->2Н20+02)

Thus, O2, which enters the mitochondria during the respiration of the organism, is necessary for the addition of hydrogen protons H. In its absence, the entire process in mitochondria stops, since the electron transport chain ceases to function. General reaction of stage III:

(2CsHbOz + 6Oz + 36ADP + 36F ---> 6C02 + 36ATP + + 42H20)

As a result of the breakdown of one glucose molecule, 38 ATP molecules are formed: at stage II - 2 ATP and at stage III - 36 ATP. The resulting ATP molecules go beyond the mitochondria and participate in all cell processes where energy is needed. Splitting, ATP gives off energy (one phosphate bond contains 40 kJ) and returns to the mitochondria in the form of ADP and F (phosphate).

light phase

The transformation of substances and energy in the process of dissimilation includes the following steps:

I stage- preparatory: complex organic substances under the action of digestive enzymes break down into simple ones, while only thermal energy is released.
Proteins ® amino acids

Fats ® glycerol and fatty acids

Starch ® glucose

II stage- glycolysis (oxygen-free): carried out in the hyaloplasm, not associated with membranes; it involves enzymes; glucose is broken down:

Stage III- oxygen: carried out in mitochondria, associated with the mitochondrial matrix and the inner membrane, enzymes participate in it, pyruvic acid undergoes cleavage

CO 2 (carbon dioxide) is released from mitochondria into the environment. The hydrogen atom is included in a chain of reactions, the end result of which is the synthesis of ATP. These reactions go in the following order:

1. The hydrogen atom H, with the help of carrier enzymes, enters the inner membrane of the mitochondria, which forms cristae, where it is oxidized:

2. Proton H + (hydrogen cation) is carried by carriers to the outer surface of the membrane of the cristae. For protons, this membrane, as well as the outer membrane of the mitochondria, is impermeable, so they accumulate in the intermembrane space, forming a proton reservoir.

3. Hydrogen electrons are transferred to the inner surface of the cristae membrane and immediately attached to oxygen with the help of the oxidase enzyme, forming a negatively charged active oxygen (anion):

4. Cations and anions on both sides of the membrane create an oppositely charged electric field, and when the potential difference reaches 200 mV, the proton channel begins to operate. It occurs in the enzyme molecules of ATP synthetase, which are embedded in the inner membrane that forms the cristae.

5. Through the proton channel, H + protons rush into the mitochondria, creating a high level of energy, most of which goes to the synthesis of ATP from ADP and F (), and the H + protons themselves interact with active oxygen, forming water and molecular O 2:

Thus, O 2 entering the mitochondria during the respiration of the organism is necessary for the addition of H + protons. In its absence, the entire process in mitochondria stops, since the electron transport chain ceases to function. General reaction of stage III:

As a result of the breakdown of one glucose molecule, 38 ATP molecules are formed: at stage II - 2 ATP and at stage III - 36 ATP. The resulting ATP molecules go beyond the mitochondria and participate in all cell processes where energy is needed. Splitting, ATP gives off energy (one phosphate bond contains 46 kJ) and returns to the mitochondria in the form of ADP and F (phosphate).

Metabolism (metabolism) 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 expenditure formed (synthesized) more complex. Example:

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

2. Energy exchange(dissimilation, catabolism, respiration) is when complex substances break down (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, and energy is generated. (cellular respiration)

The relationship of 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 doing 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 chemical bonds of decayed complex substances is converted into the energy of ATP, energy is stored in ATP.
• During plastic exchange, all substances are synthesized, and ATP breaks down. Wherein ATP energy is consumed(the energy of ATP is converted into the energy of chemical bonds of complex substances, stored in these substances).

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

Answer

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

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. What is the relationship between plastic and energy metabolism
1) plastic exchange supplies organic substances for energy
2) energy exchange supplies oxygen for plastic
3) plastic metabolism supplies minerals for energy
4) plastic exchange supplies ATP molecules for energy

Answer

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

Answer

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

Answer

3. Establish a correspondence between the signs of metabolism in humans 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
C) energy is stored in ATP molecules
D) energy is spent
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) energy, 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

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

Answer

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

Answer

Choose one, the most correct option. What process results in the synthesis of lipids in a cell?
1) dissimilation
2) biological oxidation
3) plastic exchange
4) glycolysis

Answer

Choose one, the most correct option. The value of plastic metabolism - 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 vesicles when breathing
2) body cells in the process of plastic exchange
3) the process of digestion of 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 costs?
1) the preparatory stage of energy metabolism
2) lactic acid fermentation
3) oxidation of organic substances
4) plastic exchange

Answer

1. Establish a correspondence between the processes and constituent parts 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 of the body
B) includes a preparatory stage, glycolysis and oxidative phosphorylation
C) the released energy is stored in ATP
D) water and carbon dioxide are formed
D) requires energy costs
E) occurs in chloroplasts and on ribosomes

Answer

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) change in the intensity of physiological processes and functions with different periods of oscillation
3) transmission from generation to generation of features and properties
4) absorption of necessary substances and excretion of waste products
5) maintaining a relatively constant physical and chemical composition of the internal environment

Answer

1. All but two of the terms below 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 the concepts listed below, except for two, are used to describe the plastic metabolism in the 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 for two, are used to characterize plastic exchange. Identify two terms that fall out of the general list, and write down the numbers under which they are indicated.
1) splitting
2) oxidation
3) replication
4) transcription
5) chemosynthesis

Answer

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

Answer

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

Answer

© D.V. Pozdnyakov, 2009-2019

It's called dissimilation. It is a collection of organic compounds in which a certain amount of energy is released.

Dissimilation takes place in two or three stages, depending on the type of living organisms. So, in aerobes it consists of preparatory, oxygen-free and oxygen stages. In anaerobes (organisms that are able to function in an anoxic environment), dissimilation does not require the last step.

The final stage of energy metabolism in aerobes ends with complete oxidation. In this case, the breakdown of glucose molecules occurs with the formation of energy, which partially goes to the formation of ATP.

It is worth noting that ATP synthesis occurs in the process of phosphorylation, when inorganic phosphate is added to ADP. At the same time, it is synthesized in mitochondria with the participation of ATP synthase.

What reaction occurs during the formation of this energy compound?

Adenosine diphosphate and phosphate combine to form ATP and the formation of which takes about 30.6 kJ / mol. Adenosine triphosphate, since a significant amount of it is released during the hydrolysis of precisely the high-energy bonds of ATP.

The molecular machine that is responsible for the synthesis of ATP is a specific synthase. It consists of two parts. One of them is located in the membrane and is a channel through which protons enter the mitochondria. This releases energy, which is captured by another structural part of ATP called F1. It contains a stator and a rotor. The stator in the membrane is fixed and consists of a delta region, as well as alpha and beta subunits, which are responsible for the chemical synthesis of ATP. The rotor contains gamma as well as epsilon subunits. This part spins using the energy of protons. This synthase ensures the synthesis of ATP if the protons from the outer membrane are directed towards the middle of the mitochondria.

It should be noted that the cell is characterized by spatial order. The products of chemical interactions of substances are distributed asymmetrically (positively charged ions go in one direction, and negatively charged particles go in the other direction), creating an electrochemical potential on the membrane. It consists of a chemical and an electrical component. It should be said that it is this potential on the surface of mitochondria that becomes the universal form of energy storage.

This pattern was discovered by the English scientist P. Mitchell. He suggested that substances after oxidation do not look like molecules, but positively and negatively charged ions, which are located on opposite sides of the mitochondrial membrane. This assumption made it possible to elucidate the nature of the formation of macroergic bonds between phosphates during the synthesis of adenosine triphosphate, and also to formulate the chemiosmotic hypothesis of this reaction.

Main source of energy for the cell are nutrients: carbohydrates, fats and proteins, which are oxidized with the help of oxygen. Almost all carbohydrates, before reaching the cells of the body, are converted into glucose due to the work of the gastrointestinal tract and liver. Along with carbohydrates, proteins are also broken down - to amino acids and lipids - to fatty acids. In the cell, nutrients are oxidized under the action of oxygen and with the participation of enzymes that control the reactions of energy release and its utilization.

Nearly all oxidative reactions occur in mitochondria, and the released energy is stored in the form of a macroergic compound - ATP. In the future, it is ATP, and not nutrients, that is used to provide energy for intracellular metabolic processes.

ATP molecule contains: (1) the nitrogenous base adenine; (2) pentose carbohydrate ribose, (3) three phosphoric acid residues. The last two phosphates are connected to each other and to the rest of the molecule by macroergic phosphate bonds, indicated by the symbol ~ in the ATP formula. Subject to the physical and chemical conditions characteristic of the body, the energy of each such bond is 12,000 calories per 1 mol of ATP, which is many times higher than the energy of an ordinary chemical bond, which is why phosphate bonds are called macroergic. Moreover, these bonds are easily destroyed, providing intracellular processes with energy as soon as the need arises.

When released ATP energy donates a phosphate group and is converted to adenosine diphosphate. The released energy is used for almost all cellular processes, for example, in biosynthesis reactions and during muscle contraction.

Replenishment of ATP reserves occurs by recombining ADP with a phosphoric acid residue at the expense of the energy of nutrients. This process is repeated over and over again. ATP is constantly consumed and accumulated, which is why it is called the energy currency of the cell. The turnover time of ATP is only a few minutes.

The role of mitochondria in the chemical reactions of ATP formation. When glucose enters the cell, under the action of cytoplasmic enzymes it turns into pyruvic acid (this process is called glycolysis). The energy released in this process is used to convert a small amount of ADP to ATP, less than 5% of the total energy reserves.

95% is carried out in mitochondria. Pyruvic acid, fatty acids and amino acids, formed respectively from carbohydrates, fats and proteins, are eventually converted in the mitochondrial matrix into a compound called acetyl-CoA. This compound, in turn, enters into a series of enzymatic reactions, collectively known as the tricarboxylic acid cycle or the Krebs cycle, to give up its energy.

In a loop tricarboxylic acids acetyl-CoA splits into hydrogen atoms and carbon dioxide molecules. Carbon dioxide is removed from the mitochondria, then from the cell by diffusion and excreted from the body through the lungs.

hydrogen atoms are chemically very active and therefore immediately react with oxygen diffusing into the mitochondria. The large amount of energy released in this reaction is used to convert many ADP molecules into ATP. These reactions are quite complex and require the participation of a huge number of enzymes that make up the mitochondrial cristae. At the initial stage, an electron is split off from the hydrogen atom, and the atom turns into a hydrogen ion. The process ends with the addition of hydrogen ions to oxygen. As a result of this reaction, water and a large amount of energy are formed that are necessary for the operation of ATP synthetase, a large globular protein that acts as tubercles on the surface of mitochondrial cristae. Under the action of this enzyme, which uses the energy of hydrogen ions, ADP is converted into ATP. New ATP molecules are sent from the mitochondria to all parts of the cell, including the nucleus, where the energy of this compound is used to provide a variety of functions.
This process ATP synthesis generally called the chemiosmotic mechanism of ATP formation.