Light reactions: electron flow in photosystems.
<Li> Light energy from a photon is passed among chlorophyll molecules.
<Li> The  energy  is  eventually  captured in an electron from water in
Photosystem II.
<Li> The splitting of the electron donor, water, releases oxygen.
<Li> The electron passes through an electron transport chain (ETC).
<Li> The energy from the electron is used to generate ATP.
<Li> Another photon excites chlorophyll molecules of Photosystem I.
<Li> Energy is passed among electrons to a 2nd ETC.
<Li> Energy from this 2nd ETC is stored in the electron acceptor NADPH.