What is photosynthesis? : A broader and inclusive view

In general, the word, photosynthesis, is considered synonymous with oxygenic photosynthesis, a process by which cyanobacteria, algae, aquatic, and terrestrial plants produce oxygen and carbohydrates, using light (photons), water and carbon dioxide. Further, we have anoxygenic bacterial photosynthesis where oxygen is not evolved, but a substrate, other than water, is oxidized, and rhodopsin-type systems, where ATP is produced. In principle, one could expand the concept of the term photosynthesis, provided appropriate caveats are added, to include lightdriven assimilation of molecular nitrogen, photoproduction of molecular hydrogen, and even synthesis of vitamin D in skin. We conclude with a glimpse of the rapidly developing field of artificial photosynthesis.