Chapter 24, Problem 24.50EP

(a)

Interpretation Introduction

Interpretation: To determine the molecule that crosses the outer mitochondrial membrane in the cytosol to intermediate space direction in the $\text{dihydroxyacetone phosphate}-\text{glycerol }3-\text{phosphate}$ shuttle system.

Concept introduction: In the glycolysis metabolic pathway, a glucose molecule breaks down into two pyruvate molecules.ATP and NADH are produced along with pyruvate. The net overall equation for the glycolysis process is as follows:

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

Electron transfer chain is defined as a series of biochemical reactions in which the electrons and hydrogen ions $\left({\text{H}}^{+}\right)$ that are obtained from NADH and ${\text{FADH}}_2$ react with molecular oxygen $\left({\text{O}}_2\right)$ to produce water $\left({\text{H}}_2\text{O}\right)$. NADH and ${\text{FADH}}_2$ are oxidized through the redox reactions.

A transport system shuttle that involves $\text{dihydroxyacetone phosphate}-\text{glycerol }3-\text{phosphate}$ transports the electrons from NADH across the outer membranes of mitochondria. The net overall reaction for the shuttle process is as follows:

(b)

Interpretation Introduction

Interpretation: To identify the molecule that crosses the outer mitochondrial membrane in the intermembrane space to cytosol direction in the $\text{dihydroxyacetone phosphate}-\text{glycerol }3-\text{phosphate}$ shuttle system.

Concept introduction: In the glycolysis metabolic pathway, a glucose molecule breaks down into two pyruvate molecules.ATP and NADH are produced along with pyruvate. The net overall equation for the glycolysis process is as follows:

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

Electron transfer chain is defined as a series of biochemical reactions in which the electrons and hydrogen ions $\left({\text{H}}^{+}\right)$ that are obtained from NADH and ${\text{FADH}}_2$ react with molecular oxygen $\left({\text{O}}_2\right)$ to produce water $\left({\text{H}}_2\text{O}\right)$. NADH and ${\text{FADH}}_2$ are oxidized through the redox reactions.

A transport system shuttle that involves $\text{dihydroxyacetone phosphate}-\text{glycerol }3-\text{phosphate}$ transports the electrons from NADH across the outer membrane of mitochondria. The net overall reaction for the shuttle process is as follows: