Synthesis of ATP: features of this process

Energy metabolism, which passes in all cells of a living organism, is called dissimilation. It is a set of decomposition reactions of organic compounds, in which a certain amount of energy is released.

Dissimilation takes place in two or three stages, which depends on the species of living organisms. Thus, in aerobes, energy metabolism consists of a preparatory, oxygen-free and oxygen stages. In anaerobes (organisms that are able to function in an oxygen-free environment), dissimilation does not require the last stage.

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

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

What reaction occurs when this energy compound is formed?

Adenosine diphosphate and phosphate are combined with the formation of ATP and a high-energy bond, the formation of which is consumed about 30.6 kJ / mol. Adenosine triphosphate provides cells with energy, since a significant amount of it is released when the macroergic ATP bonds are hydrolyzed.

A molecular machine that is responsible for the synthesis of ATP is a specific synthase. It consists of two parts. One of them is in the membrane and is a channel through which the protons enter the mitochondria. In this case, energy is released, which is captured by another structural part of ATP called F1. It contains a stator and a rotor. The stator in the membrane is immobile 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 is spinning using the energy of protons. This synthase provides the synthesis of ATP if protons from the outer membrane are directed toward the middle of the mitochondria.

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

This pattern was discovered by the English scientist P. Mitchell. He suggested that the substances after oxidation are not molecules, but positively and negatively charged ions, which are located on opposite sides of the mitochondrial membrane. This assumption made it possible to clarify 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.