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Glycolysis - Medical Science

Q1:

Why does the glycolytic pathway continue in the direction of glucose catabolism?

A There are essentially three irreversible reactions that act as the driving force for the pathway

B High levels of ATP keep the pathway going in a forward direction

C The enzymes of glycolysis only function in one direction

D Glycolysis occurs in either direction

ANS:A - There are essentially three irreversible reactions that act as the driving force for the pathway

The most important and very crucial steps in Glycolysis are Phosphorylation of Glucose upto the stage when Fructose 1-6 bisphosphate is formed and the irreversible step 1 i.e Glucose Phosphorylation that helps Glucose to remain in polar state not to exit the cell (Hexokinase & Glucokinase),

And Phosphorylation of Fructose 6 phosphate into Fructose 1-6 Bisphosphate (PhosphoFructoKinase 1) which is actually under regulation very close stimulation and inhibition of (ATP, Citrate) and AMP respectively and ofcose Fructose 2-6 bisphosphate (formed by PhosphoFructokinase 2) avery powerful stimulant of PFK 1, and and inhibitor of gluconeogenesis enables the cycle in one direction.