Primary processes in photosynthesis

de Martin David Kamen

Few phenomena in natural science equal photosynthesis in sweep and grandeur. It suffices to cite as evidence the annual yield of organic matter from photosynthesis, which is estimated to be between 10¹⁰ and 10¹¹ tons--an amount equivalent to the weight of metropolitan New York City [circa 1963]. Photosynthesis begins in the recesses of radiation physics and ends in the far reaches of ecology. A simple, if noncommittal definition, may provide a place to begin: photosynthesis is a series of processes in which electromagnetic energy is converted to chemical free energy which can be used for biosynthesis. Welcome to nature's most amazing phenomenon.