Question

In the hexose monophosphate shunt pathway, the number of CO₂ molecules evolved is _________.

• A. same as in glycolysis
• B. less than glycolysis
• C. more than glycolysis
• D. much lesser than glycolysis

Answer 1

Answer: (C)

Carbon dioxide evolved in HMP is higher than glycolysis. In this cycle for every molecule of CO₂ released 2 NADPH₂ are synthesized. Therefore, the complete oxidation of one glucose molecule would produce 6 CO₂ molecules or $\left(6\times 2\right)=12$ NADPH₂ molecules.
Since each NADPH₂ on its passage through the electron transport chain yields 3ATP, therefore, 12 NADPH₂ would yield $(12\times 3)=36$ ATP molecules.
Net gain of ATP is 36 -1 = 35 ATP