Plastoquinone PQ), an electron carrier of small molecular weight, is found in the electron transport chain associated with photosystem II. If PQ is not directly anchored to other membrane or cytoplasmic structures, it is probably
A) mobile in the thylakoid membrane.
B) lipid soluble.
C) a molecule that serves as a shuttle between the electron transport chain and ATP synthase.
D) both A and B.

Question

Quizplus · Accepted Answer

Since PQ is not directly anchored to other membrane or cytoplasmic structures, it is likely mobile in the thylakoid membrane. Additionally, because it is a lipid-soluble molecule, it can easily move through the hydrophobic interior of the membrane. PQ also serves as a shuttle between the electron transport chain and ATP synthase, so choice C is partially correct. Therefore, the best choice is D, as it includes both A and B.

Plastoquinone PQ), an Electron Carrier of Small Molecular Weight, Is