Question

Describe the steps involved in glycolysis (flow chart or explanation).

Answer 1

Hint: Glycolysis is a metabolic process in which one molecule of glucose is converted into two molecules of pyruvate, two hydrogen ions and one water molecule with release of energy containing molecules.

Complete answer:
Glycolysis is the metabolic process in which the one molecule of the glucose gets converted into pyruvate. This process helps in production of high energy molecules that is, ATP and NADH. End product, that is, pyruvate, then participates in many reactions in which at later stages acetyl-CoA is produced which follow up in the TCA cycle.
Flow diagram of the glycolysis:
Glycolysis take place in two phases that is:
Energy investment phase – In this ATP molecules are used to produce high energy molecules precursors.
Energy pay out phase – The precursors of ATP produce four ATP and two NADH.
Reaction 1: Glucose is converted to glucose-6-phosphate by using enzyme hexokinase.
Reaction 2: Glucose-6-phosphate is converted to fructose-6-phosphate by using isomerase enzyme.
Reaction 3: Fructose-6-phosphate is converted to fructose-1,6-bisphosphate by using enzyme Phosphofructokinase.
Reaction 4: Fructose-1,6-bisphosphate is converted to two triose sugars that is, glyceraldehyde-3-phosphate (GA3P) and dihydroxyacetone phosphate (DHAP) by using enzyme fructose-bisphosphate aldolase.
Here, the first phase of glycolysis ends and 2 ATP molecules are consumed.
Reaction 5: Dihydroxyacetone phosphate (DHAP) is converted to glyceraldehyde-3-phosphate (GA3P). And both reactions proceed further in glycolysis.
Reaction 6: Glyceraldehyde-3-phosphate (GA3P) is converted to 1,3-bisphosphoglycerate (1,3-BPG) by using enzyme glyceraldehyde phosphate dehydrogenase. Yields a molecule of NADH from reduction of NAD+.
Reaction 7: 1,3-bisphosphoglycerate (1,3-BPG) is converted to 3-phosphoglycerate (3PG) by using enzyme phosphoglycerate kinase. Leads to generation of a molecule of ATP.
Reaction 8: 3-phosphoglycerate (3PG) is converted to 2-phosphoglycerate (2PG) by using enzyme phosphoglycerate mutase.
Reaction 9: 2-phosphoglycerate is converted to phosphoenolpyruvate using enzyme enolase.
Reaction 10: Phosphoenolpyruvate gets converted into pyruvate with the help of pyruvate kinase. With the release of ATP molecules.
This is the whole process of glycolysis.

Note: Substrates which participate in glycolysis, they can enter into this process by means of three ways:
> Dietary glucose: Food which we eat and have glucose molecules, is absorbed by the bloodstream from the gastrointestinal path and enters into the glycolysis pathway.
> Glycogenolysis: This is another process in which glucose which is stored in the form of glycogen, is breakdown and gets converted into glucose again and enters into glycolysis.
> Monosaccharides: These are the carbohydrates which comes from the sources like galactose or fructose which enters into the glycolysis with different levels.