Question: what is the main difference between cyclic and noncyclic photophosphorylation?
Answer: So in non-cyclic photophosphorylation, you make oxygen, from splitting the water molecule, you make ATP using the H+ ions and you make NADPH. In cyclic photophosphorylation, you only use photosystem I. There is no splitting of water - the electrons only come from the light harvesting complex.