Answer:
Electron transfer and presence of thylakoid membrane proteins
Explanation:
The high energy electrons from chlorophyll pass through a chain of proteins called electron transport chain in the thylakoid membrane. These high energy electrons helps H+ ions to come from outside to inside membrane of thylakoid against the concentration gradient which is also contributing factor to build the concentration of H+ inside thylakoid membrane which is used to transfer phosphate to ADP during light depend reactions.
