Apentix/AP Biology/Unit 3: Cellular Energetics/Question
AP Biologyhardmcq1 pt

Dinitrophenol (DNP) ferries protons across the inner mitochondrial membrane independently of ATP synthase. Which combination best describes the metabolic state of a DNP poisoned cell?

A.ATP production rises because protons reach the matrix faster than before
B.Electron transport and oxygen consumption slow because unmet ATP demand throttles the chain
C.The proton gradient dissipates, so ATP synthesis falls even as electron transport and oxygen consumption accelerate
D.Fermentation replaces respiration because DNP disables Complex I directly

Explanation

Core Concept

ATP synthase depends wholly on the electrochemical gradient assembled by the electron transport chain. DNP offers an alternate path letting protons reenter the matrix without turning the rotor, converting gradient energy into heat. Because the gradient never builds fully, the chain faces less resistance and NADH oxidation races ahead, consuming oxygen faster. Cells burn more fuel yet bank less ATP, which explains why higher doses of DNP are lethal.

Correct Answer

CThe proton gradient dissipates, so ATP synthesis falls even as electron transport and oxygen consumption accelerate

More Unit 3: Cellular Energetics practice questions

Try a random question →

Practice more AP Biology questions with full explanations

Practice Unit 3: Cellular Energetics Questions →