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Chemiosmosis in chloroplasts and in mitochondria differs in that, in chloroplasts, protons accumulate in the

(a) thylakoid lumen, while in mitochondria they accumulate in the intermembrane space Correct
(b) cytoplasm in both cases Your answer
(c) stroma, while in mitochondria they accumulate in the matrix Your answer
(d) intermembrane space, while in mitochondria they accumulate in the matrix Your answer

Your answer: Correct answer: (a)

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Explanation

Why (a) is correct

In chloroplasts protons build up in the thylakoid lumen, while in mitochondria they build up in the intermembrane space.

Why the other options are wrong

(b) · your answer Neither organelle collects protons in the cytoplasm.
(c) · your answer In chloroplasts protons leave the stroma; in mitochondria they leave the matrix.
(d) · your answer In chloroplasts it is the lumen, not the intermembrane space.

NCERT point: In both cases, protons flow back through ATP synthase to make ATP.

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