Chapter 12.9, Problem 1QQ

Interpretation Introduction

Interpretation:

To identify the number of enzymes among the four enzyme complexes in the electron transport chain that function as proton pumps in oxidative phosphorylation.

Concept introduction:

Oxidative phosphorylation is the biochemical process for the synthesis of ATP from ADP and ${\text{P}}_{\text{i}}$. The energy required for the synthesis is transferred from the electron transport chain.

When coenzymes (NADH and FADH₂) gets oxidized, there is proton flow between the matrix and intermembrane space that is responsible for the buildup of ${\text{H}}^{+}$ ions in intermembrane space. The energy released by the proton flow is responsible for the phosphorylation of ADP. The proton flow is through the help of the enzyme ATP synthase. The reaction for the synthesis of ATP is:

  ${\text{H}}^{+}+\text{ADP}+{\text{P}}_{\text{i}}\stackrel{\text{ATP synthase}}{\to }\text{ATP}+{\text{H}}_{\text{2}}\text{O}$