Chapter 24, Problem 24.89EP

(a)

Interpretation Introduction

Interpretation: To indicate whether the statement “pyruvate is the initial reactant for glycolysis” concerning glucose metabolic pathways is true or false.

Concept introduction: Pyruvate $\left({\text{CH}}_3{\text{COCOO}}^{-}\right)$ is the conjugate base of pyruvic acid $\left({\text{CH}}_3\text{COCOOH}\right)$. Pyruvate molecule contains three carbon atoms, therefore, it is a ${\text{C}}_3$ molecule.

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

(b)

Interpretation Introduction

Interpretation: To indicate whether the statement “lactate is the initial reactant for gluconeogenesis” concerning glucose metabolic pathways is true or false.

Concept introduction: Lactate is the conjugate base of lactic acid. The structure of lactate is as follows:

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

Gluconeogenesis is an eleven-step pathway in which glucose is produced from non-carbohydrate substances.

(c)

Interpretation Introduction

Interpretation: To indicate whether the statement “glycogen is the initial reactant for glycogenolysis” concerning glucose metabolic pathways is true or false.

Concept introduction: Glucose is a monosaccharide with the molecular formula ${\text{C}}_6{\text{H}}_{12}{\text{O}}_6$. Glycogen is a polysaccharide of glucose. It serves as a form of carbohydrate storage in humans and animals. Glycogen is a source of glucose in humans and animals.

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

(d)

Interpretation Introduction

Interpretation: To indicate whether the statement “$\text{glucose 6}-\text{phosphate}$ is the initial reactant for glycogenesis” concerning glucose metabolic pathways is true or false.

Concept introduction: Glucose is a monosaccharide with the molecular formula ${\text{C}}_6{\text{H}}_{12}{\text{O}}_6$. Glycogen is a polysaccharide of glucose. It serves as a form of carbohydrate storage in humans and animals. Glycogen is a source of glucose in humans and animals.

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