Structure of photosystem I based on PDB 6YAC. Model shows only the cofactors, with the protein hidden. The system is rich in antenna molecules: chlorophyll, beta carotene, lutein and violaxanthin. The light harvesting structure funnel energy into the P700 reaction centre (in green). The high energy electrons generated flow through the carrier phylloquinone (blue) and FeS centers (yellow) to the final acceptor NADP+