The complete catabolism of each molecule of glucose produces 10 NADH in a normal

Question

The complete catabolism of each molecule of glucose produces 10 NADH in a normal mammalian cell. However, if there is no oxygen in the cell to dispose of the electrons after they traverse the electron transport chain, the NADH in the cytoplasm will be used to reduce pyruvate to lactate, regenerating NAD so that glycolysis can continue. What is the free energy of formation of lactate from NADH and pyruvate under standard conditions?

NAD+ + H+ +2e- èNADH

-0.32

Pyruvate + 2H+ 2e-è lactate

-0.185

1/2 O2 + 2H+ +2e- èH2O

0.816

Explanation / Answer

NADH + H+ ---------> NAD+ + 2H+ + 2e- + 0.32V

Pyruvate + 2H+ + 2e- ----------> Lactate -0.185V

The overall redoc potential of the reaction is +0.135V

Delta G= nFE= -2 x 96.5 KJ/V.mol x 0.135= -26.05 KJ/mol

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