Photosystem II Video (VIDEO) DOE/SLAC National Accelerator Laboratory This video is under embargo. Please login to access this video. To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video Caption The machinery responsible for photosynthesis -- while commonplace and essential to life on Earth -- is still not fully understood. One of its molecular mysteries involves how a protein complex, photosystem II, harvests energy from light and uses it to split water into hydrogen and oxygen. The process generates the oxygen in the air that we breathe. Credit SLAC National Accelerator Laboratory 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.