when light strikes chlorophyll molecules of ps ii, they lose electrons, which are ultimately replaced by _____.

When light strikes chlorophyll molecules of Photosystem II (PS II), they lose electrons, which are ultimately replaced by electrons obtained from the splitting of water molecules. This process, called photolysis, splits water into oxygen, protons, and electrons. The electrons from water restore those lost by the chlorophyll in PS II. In summary, the electrons lost by PS II chlorophyll molecules are replaced by electrons derived from splitting water molecules (H2O).