Question

The number of ATP molecules produced from one molecule of pyruvic acid during the conversion to acetyl CoA is

• A. 6
• B. 3
• C. 12
• D. 15

Answer 1

The correct option is B 3

Glycolysis is the process of a partial oxidation of glucose or similar hexose sugar into 2 molecules of pyruvic acid through a series of reactions releasing some energy (as ATP) and NADH (reduced Nicotinamide Adenine Dinucleotide).

Pyruvic acid is the end product of glycolysis. Krebs cycle is the stepwise oxidative and cyclic degradation of acetyl CoA derived from the end product of glycolysis, i.e. pyruvate. Glycolysis occurs in the cytoplasm. The Krebs cycle occurs in the matrix of mitochondria.

Pyruvate enters mitochondria from the cytoplasm and undergoes oxidative decarboxylation i.e., removal of a carboxyl group, to produce acetyl CoA, ${\mathrm{CO}}_2$, and NADH. 1 NADH molecule gives its electrons to the electron transfer chain, and through the process of oxidative phosphorylation, 3 ATP molecules are produced. So, 1 molecule of pyruvate, through its conversion to acetyl CoA, produces 3 ATP molecules.