Question

Please use this discussion to explain Glycolysis how you understand it.

Answer 1

In the initial phase of respiratory metabolism of carbohydrates glucose is degraded to pyruvic acid. The component reactions and enzymes are the same in all living cells of higher plants,animals and microorganisms. Glycolysis operates in the cytoplasm and is common to both aerobic and anaerobic respiration.

The process of glycolysis is described taking glucose after starting point. It includes two major steps.

1) conversion of glucose to Fructose 1 6 bisphosphate.

2) splitting of fructose 1 6 bisphosphate into two molecules of pyruvic acid.

A) PHOSPHORYLATION:

Glucose normally resists breaking because it is fairly stable compound.

1) glucose is phosphorylated at vi carbon in the presence of ATP and an enzyme hexokinase. This will yield glucose 6 phosphate and ADP.

2) in the next reaction glucose 6 phosphate is isomerized to Fructose 6 phosphate in the presence of phosphoglucose isomerase. This is the conversion of sugar into ketose sugar.

3) in this reaction three of glucose and Fructose 6 phosphate is again phosphorylated by 1 ATP molecule under the influence of the enzyme phosphofructokinase. So Fructose 1 6 bisphosphate and ADP are formed.

B) FORMATION OF PYRUVIC ACID:

4) the major step in the sequence of reactions is the cleavage of fructose 1 6 bisphosphate into two Triose phosphate molecules catalyzed by enzyme aldolase. The three carbon molecules are dihydroxyacetone phosphate and glycerol 3 phosphate. An equilibrium is maintained between the two drivers phosphates by the catalytic action of triose phosphate isomerase.

In this type only one triose sugar and glyceraldehyde 3 phosphate continuous along the glycolytic Pathways.

5) in this step glyceraldehyde 3 phosphate is oxidized to 1 3 bisphosphoglyceric acid by the action of glyceraldehyde phosphate dehydrogenase. The reaction involves the incorporation of inorganic phosphate and oxidation of aldehyde into acid.the coenzyme NAD+ is reduced to NADH + H +.

6) Dabangg 3 bisphosphoglyceric acid now loses one of its phosphate group ADP. In the presence of enzyme phosho glyceric kinase. The end product are 3 phosphoglyceric acid and ATP.

7) the 3 phosphoglyceric acid is letter converted into 2- phosphoglyceric acid by the activity of phosphoglycero mutase.

8)By losing 1 molecule of water to phosphoglyceric acid becomes phosphophenol pyruvic acid. This reaction is catalysed by enzyme and Anolase.

9)In the final reaction the phosphate group from phosphophenol pyruvic acid is removed with the production of pyruvic acid. ADP accept the phosphate group and forms ATP. This reaction is catalysed by pyruvate kinase.

From all the above steps we can understand that for each glucose molecules are consumed in glycolysis two molecules of pyruvic acid and two molecules of N A D H are formed and also two molecules of ATP are consumed in the first and third reactions and for molecules of ATP are regenerated in the reactions 6 and 9. Bus there is a net gain of ATP molecules in glycolysis for every glucose molecule. The reduced NADH are subsequently oxidised aerobically two wheel for molecules of ATP. The total gain in ATP molecules in glycolysis will there for B6 instead of 2 ATP molecules.