Chapter 17, Problem 1RE

RECALL Which reaction or reactions that we have met in this chapter require ATP? Which reaction or reactions produce ATP? List the enzymes that catalyze the reactions that require and that produce ATP.

Interpretation Introduction

Interpretation:

The reactions that require and produce $\text{ATP}$ are to be named and the list of enzymes that catalyze those reactions during the process of glycolysis is to be provided.

Concept introduction:

Glycolysis is a metabolic pathway that converts one molecule of glucose into two molecules of pyruvate.

Glycolysis is an anaerobic process that occurs in the absence of oxygen.

Glycolysis is the fundamental system of sugar metabolism in the body that contributes to the production of energy in the form of $\text{ATP}$ molecules.

Answer to Problem 1RE

Solution: The first step of glycolysis, which is the phosphorylation of glucose to glucose-$6$-phosphate, is catalyzed by the enzyme hexokinase and the third step of glycolysis, that is, the phosphorylation of fructose-$6$-phosphate to give fructose-$1,6$-bisphosphate is catalyzed by the phosphofructokinase enzyme. These two steps in the process of glycolysis require $\text{ATP}$ for the reaction to take place.

The step involving the phosphorylation of $\text{ADP to ATP}$, where $1,3\text{-bisphosphoglycerate}$ is converted into $3\text{-phosphoglycerate}$, is catalyzed by the enzyme phosphoglycerate kinase and the step involving the conversion of phosphophenol-pyruvate to pyruvate is catalyzed by the enzyme pyruvate kinase. These two steps in the process of glycolysis produce $\text{ATP}$.

Explanation of Solution

The phosphorylation of glucose to glucose-$6$-phosphate, that is, the first step of glycolysis, which is initiated by an enzyme called hexokinase, requires one molecule of $\text{ATP}$ (Adenosine triphosphate), which act as a source for the phosphate group, released as $\text{ADP}$(Adenosine diphosphate). Also, the phosphorylation of fructose-$6$-phosphate to give fructose-$1,6$-bisphosphate requires one molecule $\text{ATP}$ (Adenosine triphosphate), which acts as a source for the phosphate group, released as $\text{ADP}$(Adenosine diphosphate). Both the reactions result in the conversion of glucose into two molecules of glyceraldehyde-$3$-phosphate.

The step where $1,3\text{-bisphosphoglycerate}$ is converted to $3\text{-phosphoglycerate}$ as well as the step involving the conversion of phosphoenol-pyruvate to pyruvate involve the phosphorylation of $\text{ADP to ATP}$. The transfer of a phosphate group each from $1,3\text{-bisphosphoglycerate}$ and phosphoenol-pyruvate to $\text{ADP}$ occurs.

Conclusion

Glycolysis results in the production of two molecules of $\text{ATP, NADH and pyruvate}$.