Which of the following combinations is required for chemiosmosis?
Answer: (A) membrane, proton pump, proton gradient, ATP synthase. In the chemiosmotic hypothesis of ATP synthesis (taught for the photosynthesis light reaction in NCERT 11.6.3), four components are needed: a membrane (thylakoid), a proton pump, a proton gradient, and ATP synthase.
- A.membrane, proton pump, proton gradient, ATP synthase✓
- B.membrane, proton pump, proton gradient, NADP synthase
- C.proton pump, electron gradient, ATP synthase
- D.proton pump, electron gradient, NADP synthase
Correct Answer
(A) membrane, proton pump, proton gradient, ATP synthase
Solution & Explanation
In the chemiosmotic hypothesis of ATP synthesis (taught for the photosynthesis light reaction in NCERT 11.6.3), four components are needed: a membrane (thylakoid), a proton pump, a proton gradient, and ATP synthase. Energy pumps protons to create a gradient across the membrane, and ATP synthase uses the breakdown of this gradient to make ATP. Options with 'electron gradient' or 'NADP synthase' are wrong. NCERT: Class 11 Ch 11, p.142 [142:012-013]: "Chemiosmosis requires a membrane, a proton pump, a proton gradient and ATP synthase"