The breakdown of glucose is called respiration. When glucose is broken down to form energy, the process by which it is done is called respiration. Glycolysis is the first step of respiration, so let’s know about glycolysis:-
Glycolysis as its name suggests, the process of breakdown of glucose is called glycolysis. There are some cells in the body that have very little storage capacity of glucose or ATP, due to which the blood must maintain a constant supply of glucose. Glucose is carried by the blood as per the requirement of the body. The process of glycolysis occurs in the cytoplasm inside the cell, for which mitochondria are not required. If we talk about basic, then glucose is necessary for the process of glycolysis. Glucose is produced by breaking down of starch. Starch is made up of long chains of glucose which is found in plant cells. Another method for formation of glucose, in which glucose is formed when sucrose is broken down with the help of invertase enzyme. Sucrose is made up of glucose and fructose.
There are six carbons(6C) in glucose, when it is broken down, then two molecules of three carbons(3C) are formed at the end point, which is named pyruvate. The process of glycolysis starts from one molecule of glucose and ends with two molecules of pyruvate.
Process of glycolysis in step wise
Step-1:- In step 1, glucose-6-phosphate is formed by proceeds phosphate from ATP and reacting with glucose in the presence of hexokinase enzyme. When a phosphate is removed from ATP, it is converted into ADP.
Step-2:- In step 2, glucose-6-phosphate is converted to fructose-6-phosphate with the help of isomerase.
Step-3:- In step 3, with the help of the phosphofructokinase enzyme, phosphate is separate from ATP and mixed with fructose-6-phosphate, then fructose-1-6-bisphosphate is formed.
Step-4:- In step 4, Fructose-1-6-phosphate breaks down into two molecules of triose phosphate. Triose phosphate is made up of a combination of 3 carbons(3C) and a phosphate(1P). One of the two molecules of triose phosphate is the molecule aldehyde and the molecule ketone, which are interconvertible.
Step-5:- In step 5 triose phosphate has three carbons so it forms glyceraldehyde-3- phosphate and other molecules forms dihydroxyacetone phosphate. Both these molecules are interconvertible. To understand this, see step 4. By breaking down glucose, now two molecules have been formed, whichever molecule will be formed in the next step will be twice.
Step-6:- You must have read earlier that carboxylic acid is formed by the oxidation of aldehydes, similarly in step 6, glyceraldehyde-3- phosphate reacts with triose phosphate dehydrogenase enzymes and forms 1-3 bisphosphoglyceric acid.
Step-7:- In step 7 a phosphate is released from 1-3 bisphosphoglyceric acid with the help of the phosphoglyceric kinase enzyme, then 3-phosphoglyceric acid is formed. ADP is converted to ATP by extracting a phosphate.
Step-8:- In step 8, 3-phosphoglyceric acid is converted to 2-phosphoglyceric acid with the help of the phosphoglyceric mutase enzyme.
Step-9:- In step 9, 2-phosphoglyceric acid is converted to phosphoenolpyruvate with the help of enolase enzymes. It is a compound of very high energy.
Step-10:- In step 10 the energy of phosphoenolpyruvate is reduced with the help of pyruvate kinase enzyme, which converts ADP to ATP and forms pyruvate.
Glycolysis is very important for all competitive exams. If you want to read the notes of creb’s cycle then visit my website its notes are available in it.