question_answer 15)

  Energy required for ATP synthesis in PS II comes from (a) proton gradient                         (b) electron gradient      (c) reduction of glucose        (d) oxidation of glucose

Answer:

                  (a) The synthesis of ATP is directly linked to the development of proton gradient across the thylakoid membranes of a chloroplast. It results when the water molecule splits inside the inner membrane and form and ions. The energy for ATP synthesis comes from proton gradient which develops along the inner membrane, e.g., in case of mitochondria in electron transport chain and in chloroplast in the PS II. The other options (b), (c) and (d) are not involved in the synthesis of ATP molecule.