Figure (IMAGE) Kyushu University, I2CNER Caption The red circle (H2) represents a fuel cell anode patterned after hydrogenase, an electrode where electrons (e-) flow out to an external circuit. The green circle (H2O) shows a solar cell anode patterned after photosynthesis (photosystem II). The blue circle (O2) depicts a common cathode patterned after respiration (cytochrome c oxidase), an electrode where electrons flow from an external circuit. Credit Kyushu University 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.