Question

What is true about the end products of glycolysis?

• A. $2$ pyruvic acid $+2ATP+2NAD{H}_2$
• B. $2$ pyruvic acid $+2NAD{H}_2$
• C. $1$ pyruvic acid $+2ATP+2NAD{H}_2$
• D. $2$ pyruvic acid $+1ATP+1NAD{H}_2$

Answer 1

Answer: (A)

In glycolysis, two molecules of $ATP$ are consumed during two phosphorylation reactions to form fructose $1$, $6-$biphosphate. In return four molecules of $ATP$ are produced by substrate level phosphorylation (conversion of $1$, $3-$biphosphoglycerate to $3-$phosphoglycerate and phosphoenol pyruvate to pyruvate). Two molecules of $NAD{H}_2$ are formed at the time of oxidation of glyceraldehyde $3-$phosphate to $1$, $3-$biphosphoglycerate. The net reaction of glycolysis is as follows :
Glucose $+2NA{D}^{+}+2ADP+2H_{3}P{O}_4\to$
$2$ Pyruvate $+2NADH+2H^{+}+2ATP$
Each $NADH$ is equivalent to $3ATP$, so the net gain in glycolysis is $8ATP$.