A Laboratory Simulation for Coupled Cycles of Photosynthesis and Respiration

A laboratory experiment simulating the basic steps of the coupled cycles of photosynthesis and respiration has been developed. It may be applied in several versions depending on the availability of lab equipment and the chemistry education level of the students. This Photo-Blue-Bottle experiment demonstrates the light-driven reduction of a substrate and its reoxidation to release the stored energy. As in the natural processes, a visible-light-absorbing photocatalyst initiates the photoreduction and oxygen from the air is used for reoxidation of the substrate. The cyclic processes are visualized as color changes (yellow-blue-yellow) and as changes of the electrochemical potential.