In thylakoids, protons travel through ATP synthase from the thylakoid space to the stroma. Therefore, the catalytic "knobs" of ATP synthase would be located
A)on the side facing the thylakoid space.
B)on the ATP molecules themselves.
C)on the pigment molecules of photosystem I and photosystem II.
D)on the stromal side of the membrane.
E)built into the centre of the thylakoid stack (granum).

Question

Quizplus · Accepted Answer

Since protons are traveling from the thylakoid space to the stroma, the catalytic "knobs" of ATP synthase must be located on the stromal side of the membrane.

In Thylakoids, Protons Travel Through ATP Synthase from the Thylakoid