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Question #46729
The Question
2,4-Dinitrophenol (DNP) acts as a protonophore, dissipating the chemiosmotic gradient across the inner mitochondrial membrane. If a highly active cell, such as a neuron, is exposed to DNP, which of the following represents the correct physiological state of its respiratory pathways?
Options
- A.
The electron transport chain halts because the F0-F1 ATP synthase can no longer return protons to the matrix.
- B.
Oxygen consumption continues, but the cell must rely exclusively on substrate-level phosphorylation, yielding a maximum of 4 ATP per glucose.
- C.
The TCA cycle stops immediately due to the inability of NADH to be oxidized back to NAD+ by the electron transport chain.
- D.
Oxidative phosphorylation shifts to the outer mitochondrial membrane to bypass the disrupted proton gradient.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
Proton Gradient Directionality|Substrate Level Phosphorylation (SLP) Sites
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Distinguishing between ETC 'inhibitors' (which stop electron flow and oxygen consumption) and 'uncouplers' (which allow electron flow but destroy the proton gradient).
The secondary trap requires students to quantitatively recall the exact ATP yield of Substrate-Level Phosphorylation (SLP) across Glycolysis and the TCA cycle (2 + 2 = 4 ATP), filtering out the ATP normally generated by Oxidative Phosphorylation.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Cell – The Unit of Life - Class 11 |
| Concept | Active vs Passive Gradient Logic |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |