Question

How many molecules of ATP are obtained from the complete (including the fourth stage of catabolism) metabolism of one molecule of glucose?

Short answer

The answer is,

32 molecules of ATP

Step-by-step solution

Glucose

Glucose is a monosaccharide containing an aldehyde functional group and six carbon atoms. Hence it is called aldohexose. It is also called reducing sugar.

Explanation

Each molecule of glucose, while being converted to two molecules of pyruvate, forms two molecules of ATP and two molecules of NADH.

The two molecules of pyruvate form two molecules of NADH while being converted to two molecules of acetyl- CoA.

Each molecule of acetyl- CoA that enters the citric acid cycle forms three molecules of NADH, one molecule of${\text{FADH}}_{\text{2}}$ and one molecule of ATP. Therefore the two molecules of acetyl- CoA obtained from glucose form six molecules of NADH, two molecules of ${\text{FADH}}_{\text{2}}$, and two molecules of ATP.

Therefore, each glucose molecule forms four molecules of ATP, ten molecules of NADH (2+2+6), and two molecules of ${\text{FADH}}_{\text{2}}$.

Since each NADH forms 2.5 molecules of ATP and each${\text{FADH}}_{\text{2}}$ forms 1.5 molecules of ATP, one molecule of glucose forms$\text{4+(10×2.5)+(2×1.5)}$ molecules of ATP. That is, each molecule of glucose forms 32 molecules of ATP.