Chapter 24.6, Problem 2QQ

Interpretation Introduction

Interpretation: To determine the intermediate that is involved in gluconeogenesis but not in glycolysis.

Concept introduction: Glycolysis metabolic pathway is a ten-step enzyme catalyzed pathway in which a glucose molecule is converted to two pyruvate molecules. ATP and NADH-reduced coenzymes are produced along with pyruvate. The net overall equation for glycolysis is as follows:

$\text{Glucose}+2\text{ADP}+2{\text{P}}_i+2{\text{NAD}}^{+}\to 2\text{pyruvate}+2\text{NADH}+2\text{ATP}+2{\text{H}}^{+}+2{\text{H}}_2\text{O}$

In the gluconeogenesis pathway, glucose is produced from non-carbohydrate substances. The net overall equation for gluconeogenesis is as follows:

$2\text{pyruvate}+2\text{NADH}+4\text{ATP}+2\text{GTP}+2{\text{H}}_2\text{O}\to \text{Glucose}+4\text{ADP}+2\text{GDP}+6{\text{P}}_{\text{i}}+2{\text{NAD}}^{+}$

An intermediate is defined as the transient species that is formed from the reactants in the preceding step and gets consumed in the subsequent steps to generate the products. An intermediate is formed within a multi-step reaction mechanism.