Question

Why is it necessary for gluconeogenesis to incorporate other enzymes in its pathway that are different from glycolysis?

Answer 1

Glucogenesis is the process of synthesising glucose from non carbohydrate sources.This processs mainly takes place in the liver,kidney and small intestine under some conditions. Gluconeogenesis is the biosynthesis of carbohydrate from simpler,non carbohydrate precursors such as oxaloacetate and pyruvate is called gluconeogenesis.It is the synthesis of glucose/carbohydrate from non carbohydrate precursor molecules.

In gluconeogenesis conversion of pyruvate to PEP, the conversion of fructose-1,6-bP and the conversion of glucose-6-P to glucose all occur very simultaneously which is why these processes are highly regulated.It is imprtant for the organism to conserve as much energy as possible.When there is excess energy available gluneogenesis is inhibited.When energy is required gluconeogenesis is activated.  Here gluconeogenesis were simple to occur in reverse the reaction would require too much energy to be profitable to that particular organism.In ordre to overcome this problem nature has evolved three enzymes to replace the glycolysis enzyme hexokinase,Phosphofructose and pyruvate kinase when ongoing through the process of gluconeogensis. Not only that since we know glucose is the main source of energy especially for nervous sysytem and erythrocytes and also this process also helps in clearing the products of metabolism of other tissues from the blood eg:lactate proudced by muscle and erythrocytes and Glycerol which is continuously produced by adipose tissue.Here enzymes used in this process are useful in many ways.