Photosystem II Crystals (IMAGE) DOE/Lawrence Berkeley National Laboratory Caption Green crystals, millionths of a millimeter in size, preserve the molecular structure and activity of photosystem II, the molecule that photoxidizes water into molecular oxygen. Credit Image courtesy of Jan Kern, Berkeley Lab Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.