NEET Biology: Chemiosmotic hypothesis Practice Questions
15 free multiple-choice questions on Chemiosmotic hypothesis (Photosynthesis and Respiration) for NEET Biology, each with the correct answer and a step-by-step explanation. Attempt a question, then reveal the solution to check your reasoning.
Practice thousands more NEET questions in the app →Q1. The mechanism by which chemiosmosis functions is based on the differential flow of which type of ions across a membrane?
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Correct answer: D — Protons
The process relies on the movement of protons (H+) across a membrane to establish the gradient, which is the driving force for ATP synthesis.
Q2. Which molecule acts as the final acceptor for electrons, indirectly setting up the conditions for chemiosmotic coupling in respiration?
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Correct answer: B — Oxygen
Oxygen acts as the final electron acceptor in the respiratory chain. Its involvement in the redox reactions drives the establishment of the proton gradient necessary for ATP production.
Q3. In the context of oxidative phosphorylation, the proton gradient is established by the action of which process?
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Correct answer: B — Electron Transport Chain (ETC)
The Electron Transport Chain (ETC) pumps protons (H⁺) from the mitochondrial matrix into the intermembrane space, creating the proton motive force (gradient).
Q4. The Chemiosmotic hypothesis primarily explains the mechanism for the synthesis of which molecule in cellular respiration?
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Correct answer: A — ATP
The Chemiosmotic hypothesis posits that the energy stored in the proton gradient across a membrane is used to drive the synthesis of ATP.
Q5. The energy released during the oxidation of NADH and FADH₂ is ultimately used to create a proton gradient. This process is fundamentally linked to which stage of cellular respiration?
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Correct answer: D — Oxidative Phosphorylation
Oxidative phosphorylation (which includes the ETC and chemiosmosis) is the stage where the majority of ATP is generated, driven by the energy derived from redox reactions and proton pumping.
Q6. The proton motive force is established across the inner mitochondrial membrane by the energy released from which process?
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Correct answer: C — Electron transport chain (ETC)
The energy released by the sequential transfer of electrons through the ETC powers the pumping of protons, creating the proton motive force (a form of potential energy).
Q7. If the flow of electrons does not create an appropriate membrane potential, what aspect of the chemiosmotic hypothesis would be immediately violated?
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Correct answer: A — The coupling mechanism
The entire mechanism hinges on the successful creation and utilization of the proton gradient (membrane potential) resulting from the electron flow.
Q8. Which biological membrane structure is essential for the establishment of the proton gradient that powers ATP synthesis according to the Chemiosmotic hypothesis?
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Correct answer: A — the inner mitochondrial membrane
The proton gradient is established across the inner mitochondrial membrane, which is where ATP synthase is embedded and where the proton pumping occurs.
Q9. In aerobic respiration, where is the proton motive force (PMF) established in the context of oxidative phosphorylation?
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Correct answer: B — Across the inner mitochondrial membrane
The proton motive force is generated by the pumping of protons from the mitochondrial matrix into the intermembrane space by complexes of the ETC embedded in the inner mitochondrial membrane.
Q10. The Chemiosmotic hypothesis links the energy released during electron transport to the synthesis of ATP by which mechanism?
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Correct answer: C — Generation of a proton-motive force across a membrane
The Chemiosmotic hypothesis states that the energy from electron transport chain (ETC) is used to pump protons (H⁺) across a membrane, creating a proton-motive force. This force then drives the synthesis of ATP by ATP synthase.
Q11. Which component of the electron transport chain (ETC) is primarily responsible for pumping protons across the inner mitochondrial membrane during aerobic respiration?
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Correct answer: D — Complex I and Complex IV
Complex I and Complex IV of the ETC actively pump protons (H+) from the mitochondrial matrix into the intermembrane space, establishing the proton gradient necessary for chemiosmosis.
Q12. The overall efficiency of ATP production via the chemiosmotic mechanism is dependent on the magnitude of the:
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Correct answer: C — Enzyme activity
The amount of ATP synthesized is directly proportional to the magnitude of the proton motive force (the proton gradient) generated by the ETC.
Q13. Which enzyme utilizes the energy stored in the proton gradient to synthesize ATP?
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Correct answer: A — ATP synthase
ATP synthase is the molecular machine that harnesses the energy released by the flow of protons down their concentration gradient to phosphorylate ADP into ATP.
Q14. The proton gradient across the inner mitochondrial membrane represents the stored form of energy derived from which process?
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Correct answer: D — Electron Transport Chain (ETC)
The proton gradient is established by the energy released as electrons are passed down the Electron Transport Chain, which is directly linked to the oxidation of NADH and FADH₂ generated in earlier stages.
Q15. The core principle of the chemiosmotic theory is that energy released during redox reactions is coupled to the generation of:
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Correct answer: D — A proton gradient
The hypothesis states that the energy from electron transport is coupled to the formation of a proton gradient, which subsequently drives ATP synthesis.
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