They had to change they way they live which is quite difficult it is like you going to a new school in a new state and not being used to anyone
Yes, If there were no concentration gradient of protons across the thylakoid membrane, the ATP synthase would not be able to convert ADP to ATP.
The answer to the question mentioned above is the "Chloroplast".
During the light-dependent reaction of photosynthesis, chloroplast is decomposed to supply hydrogen ions tp produce NADPH, and important energy-carrying molecule used to help produce glucose during the light dependent reaction.