Chapter 13, Problem 13.73EP

Interpretation Introduction

Interpretation: To contrast the reactants in the first three steps of gluconeogenesis with the products in the last three steps of 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:

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

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

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

A reactant is defined as the substance that is initially present in the chemical reaction and gets consumed to form a new substance. A product is defined as the substance that is formed after the completion of a chemical reaction.