What’s the difference between photosystem I and II? Which one comes first? I am not even sure if this is on the exam though.
Remember photo system 2 comes first. They were named after when they were discovered. Both are a part of the light-dependent reactions. I think that the electrons that the pigment molecules get after they are excited in Photo system II are from the hydrogen in the water molecules releasing oxygen as a by-product and the pigment in photosystem I gets their electrons from the electrons generated in Photosystem II after they’ve been through the ETC. PS1 is also called P700 because the pigment absorbs this wavelength of red light the best and same is for P680 (PSII)