Primary Photosynthetic Processes: From Supercomplex to Leaf

Photosynthesis is the conversion of light energy of the sun into chemical energy by plants, green algae and cyanobacteria and literally means ‘synthesis with light’. It’s initial substrates are carbon dioxide and water, the end-products are oxygen and carbohydrates like sucrose, glucose or starch. This production of oxygen and assimilation of carbon dioxide into organic matter determines the composition of our atmosphere and provides all life forms with essential food and fuel [1].

The importance of photosynthesis was not understood until an English chemist Joseph Priestley (1733-1824) did a series of elegant experiments. He burned a candle in a closed vessel of air until the air could no longer support combustion; then he put a living plant into the container and found that, after a few days, the air in the vessel could again enable a candle to burn for a short time [2]. These experiments were the first to demonstrate that plants produce oxygen. Seven years later the Dutch physician Jan Ingenhousz discovered that also light was a crucial factor for Priestley’s experiment [3]. In the late 1700s biologists knew that at least carbon dioxide and oxygen were involved in photosynthesis, especially because of work of Lavoisier and Laplace. The work on the subject of photosynthesis that started with Priestley is continuing today and will probably be a subject of research for many more years, because photosynthesis serves as the vital link between light energy of the sun and all living creatures [4].