Question

In which of the following process 33 - 35 ATP molecules are produced per hexose molecule?

• A. Glycolysis
• B. Krebs cycle
• C. Both A and B
• D. None of the above

Answer 1

The correct option is C Both A and B

The energy yielded from one molecule of glucose ( a hexose sugar ) is 2 ATP and 2 NADH. In the presence of oxygen, one NADH reoxidize and yields about 3 ATP. Hence, glycolysis in presence of oxygen yields 8 ATP i.e. 6 ATP from the oxidation of two molecules of NADH and 2 ATP from substrate level phosphorylation).

In Krebs cycle, the energy yielded from two pyruvate molecules ( each pyruvate molecule is a 3 carbon molecule, so a hexose sugar i.e. 6 carbon compound is first broken into 2 molecules of pyruvate) is about 25 ATP

So, from these two processes, 25+8 i.e. 33 ATPs are obtained.

Hence, per hexose molecule 33 ATP are produced.

So, the correct answer is C.