Flash Clip #1.

The photons strike the pigments around the Reaction Center of Photosystems I and II in the chloroplasts.

The Reaction Center's energy level increases as indicated by the red color.

Eventually, they gain so much energy that they lose electrons. The electrons and their high energy are passed to Acceptor molecules.

At the end, The 2 photosystems are electron deficient and the the Acceptor molecules have too many  electrons.