Chapter 13, Problem 13.75EP

(a)

Interpretation Introduction

Interpretation: To determine the number of steps of gluconeogenesis and glycolysis that produce triphosphate nucleotides.

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:

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

Triphosphate nucleotides provide energy to carry out the metabolic processes in the living cells. Adenosine triphosphate (ATP), Cytidine triphosphate (CTP), Uridine triphosphate (UTP), and Guanosine triphosphate (GTP) are examples of triphosphate nucleotides.

(b)

Interpretation Introduction

Interpretation: To determine the number of steps of gluconeogenesis and glycolysis that consume triphosphate nucleotides.

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:

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

Triphosphate nucleotides provide energy to carry out the metabolic processes in the living cells. Adenosine triphosphate (ATP), Cytidine triphosphate (CTP), Uridine triphosphate (UTP), and Guanosine triphosphate (GTP) are examples of triphosphate nucleotides.