Photosystem II Crystals (image) DOE/SLAC National Accelerator Laboratory Caption These tiny green crystals, measuring just millionths of a meter, preserve the molecular structure and activity of Photosystem II, which carries out the oxygen-releasing process in photosynthesis. The chlorophyll-containing crystals, which have a boxlike structure, were studied at room temperature using ultrashort X-ray pulses at SLAC's Linac Coherent Light Source X-ray laser. The image was taken with a light microscope. Credit Credit: J. Kern, Berkeley Lab Usage Restrictions None 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.