What are the functions of ATP in the cell. The structure and functions of atp

The set of metabolic reactions that take place in the body is called metabolism.

The processes of synthesis of specific intrinsic substances from simpler ones are called anabolism, or assimilation, or plastic exchange. As a result of anabolism, enzymes are formed, substances from which cell structures are built, etc. This process is usually accompanied by energy consumption.

This energy is obtained by the body in other reactions, in which more complex substances are broken down into simple ones. These processes are called catabolism, or dissimilation, or energy exchange. The products of catabolism in aerobic organisms are CO 2 , H 2 O, ATP and

reduced hydrogen carriers (NAD∙H and NADP∙H), which accept hydrogen atoms split off from organic substances in oxidation processes. Some low-molecular substances that are formed during catabolism can later serve as precursors of substances necessary for the cell (the intersection of catabolism and anabolism).

Catabolism and anabolism are closely related: anabolism uses energy and reducing agents formed in catabolism reactions, and catabolism is carried out under the action of enzymes formed as a result of anabolism reactions.

As a rule, catabolism is accompanied by the oxidation of the substances used, and anabolism is accompanied by restoration.

plastic metabolism (anabolism)	energy metabolism (catabolism)
synthesis and accumulation (assimilation) of complex substances	breakdown of complex substances into simple ones (dissimilation)
comes with the expenditure of energy (ATP is consumed)	energy is released (ATP is synthesized)
can be a source of organic substances for energy metabolism	is a source of energy for plastic exchange
biosynthesis of proteins, fats, carbohydrates; photosynthesis (carbon synthesis by plants and blue-green algae); chemosynthesis	anaerobic respiration (= glycolysis = fermentation); aerobic respiration (oxidative phosphorylation)

Anabolism reactions in different organisms may have some differences (see the topic "Methods of obtaining energy by living organisms").

ATP - adenosine triphosphate

During catabolism, energy is released in the form of heat and in the form of ATP.

ATP is a single and universal source of cell energy supply.

ATP is unstable.

ATP is an "energy currency" that can be spent on the synthesis of complex substances in anabolism reactions.

Hydrolysis (decomposition) of ATP:

ATP + $H_(2)O$ = ADP + $H_(3)PO_(4)$ + 40 kJ/mol

energy exchange

Living organisms obtain energy from the oxidation of organic compounds.

Oxidation is the process of giving up electrons.

Consumption of received energy:

50% of the energy is released as heat into the environment;

50% of the energy goes to plastic metabolism (synthesis of substances).

In plant cells:

starch → glucose → ATP

In animal cells:

glycogen → glucose → ATP

Preparatory stage

Enzymatic breakdown of complex organic substances to simple ones in the digestive system:

protein molecules - up to amino acids

lipids - to glycerol and fatty acids

carbohydrates - to glucose

The breakdown (hydrolysis) of high-molecular organic compounds is carried out either by enzymes of the gastrointestinal tract or by enzymes of lysosomes.

All the released energy is dissipated in the form of heat.

Simple substances are absorbed by the villi of the small intestine:

amino acids and glucose - into the blood;

fatty acids and glycerol - into the lymph;

and transported to the cells of the body tissues.

The resulting small organic molecules can be used as " building material or may be further broken down (glycolysis).

At the preparatory stage, hydrolysis of the reserve substances of cells can occur: glycogen in animals (and fungi) and starch in plants. Glycogen and starch are polysaccharides and break down into monomers - glucose molecules.

glycogen breakdown

Liver glycogen is used not so much for the liver's own needs, but to maintain a constant concentration of glucose in the blood, and, therefore, ensures the supply of glucose to other tissues.

Rice. Functions of glycogen in the liver and muscles

Glycogen stored in muscles cannot be broken down into glucose due to the lack of an enzyme. The function of muscle glycogen is to release glucose-6-phosphate consumed in the muscle itself for oxidation and energy use.

The breakdown of glycogen to glucose or glucose-6-phosphate does not require energy.

Glycolysis (anaerobic stage)

glycolysis- breakdown of glucose by enzymes.

Goes in the cytoplasm, without oxygen.

During this process, glucose dehydrogenation occurs, the coenzyme NAD + (nicotinamide adenine dinucleotide) serves as a hydrogen acceptor.

As a result of a chain of enzymatic reactions, glucose is converted into two molecules of pyruvic acid (PVA), while a total of 2 ATP molecules and a reduced form of the hydrogen carrier NAD H2 are formed:

$C_(6)H_(12)O_(6)$ + 2ADF + 2$H_(3)RO_(4)$ + 2$OVER^(+)$ → 2$C_(3)H_(4)O_( 3)$ + 2ATP + 2$H_(2)O$ + 2($NADH+H^(+)$).

The further fate of PVC depends on the presence of oxygen in the cell:

if there is no oxygen, yeast and plants alcoholic fermentation, at which acetaldehyde is formed first, and then ethyl alcohol:

$C_(3)H_(4)O_(3)$ → $CO_(2)$ + $CH_(3)SON$,

$CH_(3)SON$ + $NADH+H^(+)$ → $C_(2)H_(5)OH$ + $NADH^(+)$ .

In animals and some bacteria, with a lack of oxygen, lactic acid fermentation occurs with the formation of lactic acid:

$C_(3)H_(4)O_(3)$ + $NADH+H^(+)$ → $C_(3)H_(6)O_(3)$ + $NADH^(+)$.

As a result of glycolysis of one glucose molecule, 200 kJ are released, of which 120 kJ is dissipated in the form of heat, and 80 kJ is stored in bonds 2 ATP molecules.

respiration, or oxidative phosphorylation (aerobic stage)

Oxidative phosphorylation- the process of ATP synthesis with the participation of oxygen.

Goes on the membranes of mitochondrial cristae in the presence of oxygen.

Pyruvic acid, formed during the oxygen-free breakdown of glucose, is oxidized to the final products CO2 and H2O. This multi-step enzymatic process is called the Krebs cycle, or the tricarboxylic acid cycle.

As a result of cellular respiration, during the breakdown of two molecules of pyruvic acid, 36 ATP molecules are synthesized:

2$C_(3)H_(4)O_(3)$ + 32$O_(2)$ + 36ADP + 36$H_(3)PO_(4)$ → 6$CO_(2)$ + 58$H_( 2) O$ + 36ATP.

In addition, it must be remembered that two ATP molecules are stored during the oxygen-free breakdown of each glucose molecule.

The overall reaction for the breakdown of glucose to carbon dioxide and water is as follows:

$C_(6)H_(12)O_(6)$ + 6$O_(2)$ + 38ADP → 6$CO_(2)$ + 6$H_(2)O$ + 38ATP + Qt,

where Qt is thermal energy.

Thus, oxidative phosphorylation generates 18 times more energy (36 ATP) than glycolysis (2 ATP).

All living processes are based on atomic and molecular motion. Both the respiratory process and cellular development, division are impossible without energy. The source of energy supply is ATP, what it is and how it is formed, we will consider further.

Before studying the concept of ATP, it is necessary to decipher it. This term means nucleoside triphosphate, which is essential for energy and material metabolism in the body.

This is a unique energy source underlying biochemical processes. This compound is fundamental for enzymatic formation.

ATP was discovered at Harvard in 1929. The founders were scientists at Harvard Medical School. These included Karl Loman, Cyrus Fiske and Yellapragada Subbarao. They identified a compound that resembled the adenyl nucleotide of ribonucleic acids in structure.

A distinctive feature of the compound was the content of three phosphoric acid residues instead of one. In 1941, the scientist Fritz Lipmann proved that ATP has an energy potential within the cell. Subsequently, a key enzyme was discovered, which was called ATP synthase. Its task is the formation of acidic molecules in the mitochondria.

ATP is the energy accumulator in cell biology and is essential for the successful implementation of biochemical reactions.

The biology of adenosine triphosphoric acid suggests its formation as a result of energy metabolism. The process consists of creating 2 molecules in the second step. The remaining 36 molecules appear in the third stage.

The accumulation of energy in the structure of the acid occurs in the binder between the phosphorus residues. In the case of detachment of 1 phosphorus residue, an energy release of 40 kJ occurs.

As a result, the acid is converted to adenosine diphosphate (ADP). Subsequent phosphate detachment promotes the production of adenosine monophosphate (AMP).

It should be noted that the plant cycle involves the reuse of AMP and ADP, which results in the reduction of these compounds to an acid state. This is provided by the process.

Structure

Disclosure of the essence of the compound is possible after studying which compounds are part of the ATP molecule.

What compounds are in acid?

3 residues of phosphoric acid. Acid residues are combined with each other through energy bonds of an unstable nature. It is also found under the name orthophosphoric acid;
adenine: Is a nitrogenous base;
Ribose: It is a pentose carbohydrate.

The inclusion of these elements in ATP gives it a nucleotide structure. This allows the molecule to be classified as a nucleic acid.

Important! As a result of the splitting off of acid molecules, energy is released. The ATP molecule contains 40 kJ of energy.

Education

The formation of the molecule occurs in mitochondria and chloroplasts. The fundamental moment in the molecular synthesis of acid is the dissimilation process. Dissimilation is the process of transition of a complex compound to a relatively simple one due to destruction.

As part of the synthesis of acid, it is customary to distinguish several stages:

Preparatory. The basis of splitting is the digestive process, provided by the enzymatic action. The food that enters the body is destroyed. Fat is broken down into fatty acids and glycerol. Proteins are broken down into amino acids, starch is broken down into glucose. The stage is accompanied by the release of thermal energy.
Anoxic, or glycolysis. The process of disintegration is the basis. Glucose breakdown occurs with the participation of enzymes, while 60% of the released energy is converted into heat, the rest remains in the composition of the molecule.
Oxygen, or hydrolysis; Occurs within the mitochondria. Occurs with the help of oxygen and enzymes. The oxygen exhaled by the body is involved. Ends complete. It implies the release of energy to form a molecule.

There are the following ways of molecular formation:

Phosphorylation of a substrate nature. Based on the energy of substances as a result of oxidation. The prevailing part of the molecule is formed in mitochondria on membranes. It is carried out without the participation of membrane enzymes. It takes place in the cytoplasmic part through glycolysis. The option of formation due to the transportation of a phosphate group from other high-energy compounds is allowed.
Phosphorylation of an oxidative nature. Occurs due to an oxidative reaction.
Photophosphorylation in plants during photosynthesis.

Meaning

The fundamental importance of the molecule for the body is revealed through the function of ATP.

ATP functionality includes the following categories:

Energy. Provides the body with energy, is the energy basis of physiological biochemical processes and reactions. Occurs due to 2 high-energy bonds. It implies muscle contraction, the formation of a transmembrane potential, the provision of molecular transport through membranes.
basis of synthesis. It is considered the starting compound for the subsequent formation of nucleic acids.
Regulatory. Underlies the regulation of most biochemical processes. Provided by belonging to the allosteric effector of the enzymatic series. It affects the activity of regulatory centers by strengthening or suppressing them.
Intermediary. It is considered a secondary link in the transmission of a hormonal signal to the cell. It is a precursor to the formation of cyclic ADP.
mediator. It is a signaling substance in synapses and other cellular interactions. Provides purinergic signaling.

Among the above points, the dominant place is given to the energy function of ATP.

It is important to understand, no matter what function ATP performs, its value is universal.

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Summing up

The basis of physiological and biochemical processes is the existence of the ATP molecule. The main task of the connections is energy supply. Without connection, the vital activity of both plants and animals is impossible.

In contact with

ATP, or adenosine triphosphoric acid in full, is the "accumulator" of energy in the cells of the body. No bio chemical reaction does not pass without the participation of ATP. ATP molecules are found in DNA and RNA.

Composition of ATP

The ATP molecule has three components: three phosphoric acid residues, adenine and ribose. That is, ATP has the structure of a nucleotide and refers to nucleic acids. Ribose is a carbohydrate and adenine is a nitrogenous base. The remains of the acid are united with each other by unstable energy bonds. Energy appears when acid molecules are split off. The separation occurs due to biocatalysts. After detachment, the ATP molecule is already converted into ADP (if one molecule is cleaved off) or AMP (if two acid molecules are cleaved off). With the separation of one molecule of phosphoric acid, 40 kJ of energy is released.

Role in the body

ATP plays not only an energy role in the body, but also a number of others:

is the result of the synthesis of nucleic acids.
regulation of many biochemical processes.
signaling substance in other cell interactions.

ATP synthesis

ATP production takes place in chloroplasts and mitochondria. The most important process in the synthesis of ATP molecules is dissimilation. Dissimilation is the destruction of the complex to the simpler.

The synthesis of ATP does not take place in one stage, but in three stages:

The first stage is preparatory. Under the action of enzymes in digestion, the decay of what we have absorbed occurs. In this case, fats decompose to glycerol and fatty acids, proteins to amino acids, and starch to glucose. That is, everything is prepared for further use. Thermal energy is released
The second step is glycolysis (anoxic). The breakdown occurs again, but here the glucose is also degraded. Enzymes are also involved. But 40% of the energy remains in ATP, and the rest is spent as heat.
The third stage is hydrolysis (oxygen). It occurs already in the mitochondria themselves. Here, both the oxygen that we inhale and enzymes take part. After complete dissimilation, energy is released for the formation of ATP.

The most important substance in the cells of living organisms is adenosine triphosphate or adenosine triphosphate. If we enter the abbreviation of this name, we get ATP (eng. ATP). This substance belongs to the group of nucleoside triphosphates and plays a leading role in the metabolic processes in living cells, being an indispensable source of energy for them.

In contact with

The discoverers of ATP were the biochemists of the Harvard School of Tropical Medicine - Yellapragada Subbarao, Karl Loman and Cyrus Fiske. The discovery occurred in 1929 and became a major milestone in the biology of living systems. Later, in 1941, the German biochemist Fritz Lipmann found that ATP in cells is the main energy carrier.

The structure of ATP

This molecule has a systematic name, which is written as follows: 9-β-D-ribofuranosyladenine-5'-triphosphate, or 9-β-D-ribofuranosyl-6-amino-purine-5'-triphosphate. What compounds are in ATP? Chemically, it is the triphosphate ester of adenosine - derivative of adenine and ribose. This substance is formed by the connection of adenine, which is a purine nitrogenous base, with the 1'-carbon of ribose using a β-N-glycosidic bond. The α-, β-, and γ-molecules of phosphoric acid are then sequentially attached to the 5'-carbon of the ribose.

Thus, the ATP molecule contains compounds such as adenine, ribose, and three phosphoric acid residues. ATP is a special compound containing bonds that release a large amount of energy. Such bonds and substances are called macroergic. During the hydrolysis of these bonds of the ATP molecule, an amount of energy from 40 to 60 kJ / mol is released, while this process is accompanied by the elimination of one or two phosphoric acid residues.

This is how these chemical reactions are written:

1). ATP + water → ADP + phosphoric acid + energy;
2). ADP + water → AMP + phosphoric acid + energy.

The energy released during these reactions is used in further biochemical processes that require certain energy inputs.

The role of ATP in a living organism. Its functions

What is the function of ATP? First of all, energy. As mentioned above, the main role of adenosine triphosphate is the energy supply of biochemical processes in a living organism. This role is due to the fact that, due to the presence of two high-energy bonds, ATP acts as an energy source for many physiological and biochemical processes that require large energy costs. Such processes are all reactions of the synthesis of complex substances in the body. This is, first of all, the active transfer of molecules through cell membranes, including participation in the creation of an intermembrane electrical potential, and the implementation of muscle contraction.

In addition to the above, we list a few more, no less important functions of ATP, such as:

How is ATP formed in the body?

Synthesis of adenosine triphosphoric acid is ongoing, because the body always needs energy for normal life. At any given moment, there is very little of this substance - about 250 grams, which are an "emergency reserve" for a "rainy day". During illness, there is an intensive synthesis of this acid, because a lot of energy is required for the work of the immune and excretory systems, as well as the body's thermoregulation system, which is necessary for effective fight with an onset of illness.

Which cell has the most ATP? These are cells of muscular and nervous tissues, since energy exchange processes are most intensive in them. And this is obvious, because the muscles are involved in the movement that requires contraction. muscle fibers, and neurons transmit electrical impulses, without which the work of all body systems is impossible. Therefore, it is so important for the cell to maintain a constant and high level of adenosine triphosphate.

How can adenosine triphosphate molecules be formed in the body? They are formed by the so-called phosphorylation of ADP (adenosine diphosphate). This chemical reaction looks like this:

ADP + phosphoric acid + energy→ATP + water.

Phosphorylation of ADP occurs with the participation of such catalysts as enzymes and light, and is carried out in one of three ways:

Both oxidative and substrate phosphorylation use the energy of substances oxidized in the course of such synthesis.

Conclusion

Adenosine triphosphoric acid is the most frequently updated substance in the body. How long does an adenosine triphosphate molecule live on average? In the human body, for example, its life span is less than one minute, so one molecule of such a substance is born and decays up to 3000 times per day. Amazingly, during the day the human body synthesizes about 40 kg of this substance! So great is the need for this domestic energy" for us!

The whole cycle of synthesis and further use of ATP as an energy fuel for metabolic processes in the organism of a living being is the very essence of energy metabolism in this organism. Thus, adenosine triphosphate is a kind of "battery" that ensures the normal functioning of all cells of a living organism.

In biology, ATP is the source of energy and the basis of life. ATP - adenosine triphosphate - is involved in metabolic processes and regulates biochemical reactions in the body.

What is this?

To understand what ATP is, chemistry will help. The chemical formula of the ATP molecule is C10H16N5O13P3. Remembering the full name is easy if you break it down into its component parts. Adenosine triphosphate or adenosine triphosphoric acid is a nucleotide consisting of three parts:

adenine - purine nitrogenous base;
ribose - monosaccharide related to pentoses;
three residues of phosphoric acid.

Rice. 1. The structure of the ATP molecule.

A more detailed breakdown of ATP is presented in the table.

ATP was first discovered by Harvard biochemists Subbarao, Loman, and Fiske in 1929. In 1941, the German biochemist Fritz Lipmann established that ATP is the energy source of a living organism.

Energy generation

Phosphate groups are interconnected by high-energy bonds that are easily destroyed. During hydrolysis (interaction with water), the bonds of the phosphate group break down, releasing a large amount of energy, and ATP is converted into ADP (adenosine diphosphoric acid).

Conventionally, the chemical reaction looks like this:

ATP synthesis

ATP is located in the cytoplasm, nucleus, chloroplasts, and mitochondria. ATP synthesis in an animal cell occurs in mitochondria, and in a plant cell - in mitochondria and chloroplasts.

ATP is formed from ADP and phosphate with the expenditure of energy. This process is called phosphorylation:

ADP + H3PO4 + energy → ATP + H2O

Rice. 3. Formation of ATP from ADP.

IN plant cells Phosphorylation occurs during photosynthesis and is called photophosphorylation. In animals, the process occurs during respiration and is called oxidative phosphorylation.

In animal cells, ATP synthesis occurs in the process of catabolism (dissimilation, energy metabolism) during the breakdown of proteins, fats, carbohydrates.

Functions

From the definition of ATP, it is clear that this molecule is capable of providing energy. In addition to energy, adenosine triphosphoric acid performs other features:

is a material for the synthesis of nucleic acids;
is part of enzymes and regulates chemical processes, speeding up or slowing down their course;
is a mediator - transmits a signal to synapses (points of contact of two cell membranes).

What have we learned?

From the 10th grade biology lesson, we learned about the structure and functions of ATP - adenosine triphosphoric acid. ATP is made up of adenine, ribose, and three phosphoric acid residues. During hydrolysis, phosphate bonds are destroyed, which releases the energy necessary for the life of organisms.

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