As electrons flow down respiratory chains, their free energy is conserved as ATP. What is this ATP-generating process called in bioenergetics?

Introduction / Context:
Cells harness the energy from electron transfer to synthesize ATP, the universal energy currency. In aerobic and many anaerobic respirations, the bulk of ATP is made by a membrane-associated mechanism that couples redox energy to phosphorylation of ADP.

Given Data / Assumptions:

• Electrons flow through an electron transport chain.
• Free energy is conserved as ATP.
• We must choose the standard term for this coupling mechanism.

Concept / Approach:
Oxidative phosphorylation is the process in which redox reactions drive proton pumping to build a transmembrane proton motive force. ATP synthase then uses this gradient to convert ADP + Pi into ATP. This differs from substrate-level phosphorylation, where ATP is made directly via high-energy intermediates in glycolysis or the TCA cycle.

Step-by-Step Solution:

Verification / Alternative check:
Standard biochemistry texts define oxidative phosphorylation exactly as ATP synthesis driven by redox-linked proton gradients across membranes (mitochondrial inner membrane, bacterial plasma membrane).

Why Other Options Are Wrong:

• Electromotive potential: describes the gradient, not the ATP-forming process.
• Dehydrogenations: specific redox reactions (removing hydrogen) but not the ATP synthesis mechanism.
• None of these: incorrect because the precise term is provided.

Common Pitfalls:
Confusing oxidative phosphorylation with substrate-level phosphorylation; the former requires a functional electron transport chain and proton gradient.

Final Answer:
oxidative phosphorylation