Glycolysis pathway major enzymes explained easily

Glycolysis

Glycolysis  (glyco = sugar; lysis = breaking)

• Glycolysis involves the breakdown (Catabolic process) of a sugar molecule (6C)  to yield two pyruvate molecules (3C)

• Glycolysis takes place inside the cytoplasm of the cell

• Glycolysis produces 4 ATP's and 2 NADH, but uses 2 ATP's in the process for a net of 2 ATP and 2 NADH

• Net ATP production of Glycolysis is 2 ATP

• Glycolysis does not require O2

In totto glycolysis can be represented as ::

C₆H₁₂O₆ + 2 NAD⁺ + 2 ADP + 2 P —–> 2 pyruvic acid, (CH₃(C=O)COOH + 2 ATP + 2            NADH + 2 H⁺

Major Steps in glycolysis

a.Glucose (6C) is broken down into 2 molecules of  PGAL's (Phosphoglyceraldehyde - 3Carbon molecules)

b.The 2 PGAL's (3C) are converted to 2 pyruvates

Glucose broken down into 2 molecules of  PGAL

1.D-Glucose gets converted into Glucose-6-phosphate by phosphorylation , with the help of Hexokinase enzyme , one ATP is used in the process

2.Rearrangement of Glucose-6-phosphate(6 membered ring) into Fructose-6-phosphate (5 membered ring) with the help of Phosphoglucose isomerase enzyme

3.Fructose-6-phosphate is converted into Fructose-1,6bisphosphate in presence of enzyme Phosphofructokinase , Mg is cofactor , one ATP is used in the process

4. Fructose 1, 6-bisphosphate is converted into two sugars that are isomers of each other - Dihydroxyacetone phosphate  (DHAP) and Glyceraldehyde 3-phosphate (GAP) , in the presence of enzyme Aldolase 

5. The enzyme triophosphate isomerase inter- converts rapidly the molecules Dihydroxyacetone phosphate (DHAP) into Glyceraldehyde 3-phosphate (G3P/ GA3P/ GADP/GAP/TP/GALP or PGAL) so net 2 molecules of PGAL are formed

2 PGAL's (3C) are converted to 2 pyruvates

6. Glyceraldehyde-3-phosphate dehydrogenase dehydrogenates and adds an inorganic phosphate to glyceraldehyde 3-phosphate to produce 2 molecules of   1,3-bisphosphoglycerate , simultaneously each PGAL molecule contribute two electrons and a hydrogen ion to NAD+ to form NADH

7. a molecule of 1,3-bisphosphoglycerate is converted to 3-phosphoglycerate by  Phosphoglycerate kinase enzyme  , the phosphate group formed converts  ADP to form ATP , here 2 ATP molecules are produced

8. Rearrangement of the phosphate group on 3 phosphoglycerate(3^rd carbon) into 2 phosphoglycerate (2^nd carbon atom) by enzyme phosphoglycero mutase

9.Removal of  a molecule of water (dehydration) from 2-phosphoglycerate to form phosphoenolpyruvic acid (PEP) by enzyme enolase , here a net of 2 (PEP) molecules are formed

10. Phosphoenolpyruvate gets converted into  Pyruvate with the help of  enzyme pyruvate kinase , here a phosphate group is transferred to ADP and hence ATP produced , in total 2 molecules of ATP produced

 

NET end product of glycolysis produces --> 2 molecules of pyruvic acid , 2 molecules of ATP(visible) ,2 molecules of NADH

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