Photosystem II Illustration (IMAGE) Georgia Institute of Technology Caption Photosystem II is a complex of larger molecules arranged in a protein structure. It includes beta-carotene, chlorophyll, a manganese-calcium-oxygen cluster and a supporting protein stabilizer, which looks like a woven tube, in aqua-green in this illustration. Breathable oxygen, or O2, is produced in the bottom center, at the cluster, which would be at the top of the tubular stabilizing weave. Credit Curtis Neveu 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.