Out of 9 reactions in glycolysis process, 1st, 3rd and 9th reactions are unidirectional, rest are bidirectional. The reactions are:
1. Glucose 6-phosphate is produced from glucose by the action of hexokinase enzyme. During this reaction, ADP takes part and produces ATP.
2. Fructose 6 phosphate is produced from glucose 6 phosphate under the influence of phosphoglucoisomerase enzyme. The reaction is bidirectional.
3. In the presence of the enzyme phosphofructokinase, fructose 6-phosphate is converted to fructose 1, 6-bisphosphate. At this time, ATP takes part in the reaction and produces ADP.
4. 3-phosphoglyceraldehyde and dihydroxyacetone phosphate are produced from fructose 1,6 bisphosphate by the action of aldolase enzyme. The reaction is bidirectional.
5. 1, 3 bisphosphoglyceric acid is produced from 3 phosphoglyceraldehyde under the influence of phosphoglyceral dehydrogenase enzyme. At this time, NADP participates in the reaction to form NADPH+H+. The reaction is bidirectional.
6. Phosphoglyceric acid is converted to 1, 3 bisphosphoglyceric acid, 3-phosphoglyceric acid with the help of kinase enzyme. During this reaction, ADP takes part and produces ATP. The reaction is bidirectional.
7. 2-phosphoglyceric acid is formed from 3-phosphoglyceric acid in the presence of phosphoglyceromutase enzyme. The reaction is bidirectional.
8. 2-phosphoenol pyruvic acid is produced from 2-phosphoglyceric acid by the action of inolase enzyme. The reaction is bidirectional.
9. Pyruvic acid is produced from 2-phosphoenol pyruvic acid under the action of pyruvic acid kinase enzyme. During this reaction, ADP takes part and generates ATP.