Glycolysis is ... And the general information is the oxidation of glucose

In this article, we will consider in detail aerobic glycolysis, its processes, and analyze the stages and stages. We will become acquainted with the anaerobic oxidation of glucose, learn about evolutionary modifications of this process and determine its biological significance.

What is glycolysis

Glycolysis is one of three forms of glucose oxidation, in which the oxidation process itself is accompanied by the release of energy, which is stored in NADH and ATP. In the process of glycolysis, two molecules of pyruvic acid are obtained from the glucose molecule.

Glycolysis is a process that occurs under the influence of various biological catalysts - enzymes. The main oxidizer is oxygen-O ₂ , but glycolysis can also occur in its absence. This type of glycolysis is called anaerobic glycolysis.

The process of glycolysis in the absence of oxygen

Anaerobic glycolysis is a stepwise process of glucose oxidation, in which glucose is not completely oxidized. One molecule of pyruvic acid is formed. And from the energy point of view, glycolysis without the participation of oxygen (anaerobic) is less beneficial. However, when oxygen enters the cell, the anaerobic oxidation process can become aerobic and proceed in a full-fledged form.

Mechanisms of glycolysis

The process of glycolysis is the decomposition of six-carbon glucose into pyruvate three-carbon in the form of two molecules. The process itself is divided into 5 stages of preparation and 5 stages, in which energy is stored in ATP.

The process of glycolysis from 2 stages and 10 stages looks as follows:

• 1 stage, step 1 - phosphorylation of glucose. On the sixth carbon atom in glucose, the saccharide itself is activated through phosphorylation.
• Step 2 - isomerization of glucose-6-phosphate. At this stage, the phosphoglucose isomerase catalyzes glucose into fructose-6-phosphate.
• Stage 3 - Fructose-6-phosphate and its phosphorylation. This stage consists in the formation of fructose-1,6-diphosphate (aldolase) by the action of phosphofructokinase-1, which accompanies the phosphoryl group from adenosine triphosphate to the fructose molecule.
• Step 4 is the process of cleavage of the aldolase with the formation of two molecules of triose phosphate, namely, Eldose and ketose.
• Stage 5 - triisophosphates and their isomerization. At this stage, glyceraldehyde-3-phosphate is sent to subsequent stages of glucose cleavage, and dihydroxyacetone phosphate passes into the form of glyceraldehyde-3-phosphate under the influence of the enzyme.
• Stage 2, step 6 (1) - Glycereraldehyde-3-phosphate and its oxidation - the stage in which the molecule is oxidized and phosphorylated to diphosphoglycerate-1,3.
• Step 7 (2) - is aimed at transferring a group of phosphates to ADP with 1,3-diphosphoglycerate. The final products of this stage are the formation of 3-phosphoglycerate and ATP.
• Step 8 (3) is the transition from 3-phosphoglycerate to 2-phosphoglycerate. This process occurs under the influence of the enzyme phosphoglycerate mutase. An obligatory condition for the chemical reaction to occur is the presence of magnesium (Mg).
• Stage 9 (4) - 2 phosphoglycert is dehydrated.
• Step 10 (5) - in ADP and PEP are transferred phosphates obtained as a result of the passage of the previous stages. The energy from phosphoenepirovalate is transferred to ADP. The reaction requires the presence of potassium ions (K) and magnesium (Mg).

Modified forms of glycolysis

The glycolysis process can be accompanied by additional production of 1,3 and 2,3-bisphosphoglycerates. 2,3-phosphoglycerate under the influence of biological catalysts is able to return to glycolysis and pass into the form of 3-phosphoglycerate. The role of these enzymes is diverse, for example, 2,3-bisphosphoglycerate, being in hemoglobin, causes oxygen to pass into tissues, promoting dissociation and lowering the affinity of O ₂ and erythrocytes.

Many bacteria change the forms of glycolysis at various stages, reducing their total amount or modifying them under the influence of different enzymes. A small part of anaerobes has other methods of carbohydrate decomposition. Many thermophiles do have only 2 enzymes of glycolysis, this is enolase and pyruvate kinase.

Glycogen and starch, disaccharides and other types of monosaccharides

Aerobic glycolysis is a process characteristic of other types of carbohydrates, and specifically it is inherent in starch, glycogen, most disaccharides (manos, galactose, fructose, sucrose and others). The functions of all types of carbohydrates are generally aimed at obtaining energy, but can differ in the specific nature of their purpose, use, etc. For example, glycogen is susceptible to glycogenesis, which is essentially a phospholitic mechanism aimed at obtaining energy during the cleavage of glycogen. Glycogen itself can be stored in the body as a reserve source of energy. So, for example, glucose, obtained during food intake, but not assimilated by the brain, accumulates in the liver and will be used with a lack of glucose in the body in order to protect the individual from serious disruptions of homeostasis.

The value of glycolysis

Glycolysis is unique, but not the only type of glucose oxidation in the body, the cell of both prokaryotes and eukaryotes. The glycolysis enzymes are water-soluble. The reaction of glycolysis in certain tissues and cells can occur only in this way, for example, in the brain and cells of the liver nephrons. Other ways of oxidizing glucose in these organs are not used. However, glycolysis functions are not the same everywhere. For example, fatty tissues and liver during digestion extract the necessary substrates from glucose for the synthesis of fats. Many plants use glycolysis as a way to extract most of the energy.