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Chemiosmotic theory of ATP synthesis in the chloroplasts and mitochondria is based on
A
Membrane potential
B
Accumulation of K ions
C
Proton gradient
D
Accumulation of Na ions
Detailed Solution
The chemiosmotic theory was proposed by Peter Mitchell.
In chloroplasts, protons accumulate inside the thylakoid lumen due to the splitting of water and the pumping of protons by the electron transport chain.
In mitochondria, protons are pumped from the matrix into the intermembrane space by the electron transport chain.
This creates a proton gradient (a difference in $H^+$ concentration, and hence pH, across the membrane).
When the protons flow back across the membrane through the $F_0$ channel of the ATP synthase, the energy released is used by the $F_1$ part to synthesise ATP from ADP and Pi.
So ATP synthesis is based on the proton gradient; it does not depend on the accumulation of $K^+$ or $Na^+$ ions.
In chloroplasts, protons accumulate inside the thylakoid lumen due to the splitting of water and the pumping of protons by the electron transport chain.
In mitochondria, protons are pumped from the matrix into the intermembrane space by the electron transport chain.
This creates a proton gradient (a difference in $H^+$ concentration, and hence pH, across the membrane).
When the protons flow back across the membrane through the $F_0$ channel of the ATP synthase, the energy released is used by the $F_1$ part to synthesise ATP from ADP and Pi.
So ATP synthesis is based on the proton gradient; it does not depend on the accumulation of $K^+$ or $Na^+$ ions.