Chapter 21, Problem 6P

$\Delta$pH and $\Delta$ $\psi$ in the Chloroplast Proton-Motive Force (Integrates with Chapter 20.) In mitochondria, the membrane potential ( $\Delta$ $\psi$) contributes relatively more to $\Delta$p (proton-motive force) than does the pH gradient ( $\Delta$pH). The reverse is true in chloroplasts. Why do you suppose that the proton-motive force in chloroplasts can depend more on $\Delta$pH than mitochondria can? Why is ( $\Delta$ $\psi$) less in chloroplasts than in mitochondria?