The Role of Chlorophyll in Photosynthesis.

X y effort to understand the basis of life on this planet must always come back to photosynthesis: the process that enables plants to grow by utilizing carbon dioxide (C02), water (H20) and a tiny amount of minerals, Photosynthesis is the one large-scale process that converts simple, stable, in­ organic compounds into the energy-rich combination of organic matter and oxy­ gen and thereby makes abundant life on earth possible, Photosynthesis is the source of all living matter on earth, and of all biological energy, The overall reaction of photosynthesis can be summarized in the following equation: CO2 + H20 + light�(CH20) + O2 + 112,000 calories of energy per mole, (CH20) stands for a carbohydrate; �or ;, glucose: (CH2,?)G' "Mole" 1S short for gram molecule : one gram multiplied by the molecular weight of the substances in question-in this case carbohydrate and oxygen, When one of us first summarized the state of knowledge of photosynthesis 17 years ago, the whole process was still heavily shrouded in fog [see "Photo­ synthesis," by Eugene L Rabinowitch; SCIENTIFIC AMERICAN, August, 1958]. Five years later investigation had pene­ b'ated the mists sufficiently to disclose some of the main features of the proc­ ess [see "Progress in Photosynthesis," by Eugene L Rabinowitch; SCIENTIFIC AMERICAU, November, 1953]. Since then much new knowledge has been accumulated; in particular the sequence of chemical steps that convert carbon dioxide into carbohydrate is now under­ stood in considerable detail [see "The Path of Carbon in Photosynthesis," by