More on redox potentials and how they are exploited in photosynthesis. Link to page analyzing the energy changes that occur during photosynthesis. The only exit for these protons is through the ATP synthase complex. As in mitochondria , the energy released as these electrons flow down their gradient is harnessed to the synthesis of ATP . The process is called chemiosmosis and is an example of facilitated diffusion.
Carotenoids help fill in the gap by strongly absorbing green light.
The entire complex ensures that most of the energy of light will be trapped and passed on to the reaction center chlorophylls.