THE FIRST STEP IN PHOTOSYNTHESIS: EVIDENCE FOR ITS ELECTRONIC NATURE

Abstract

The first step in photosynthesis appears to be the separation of an electron and a hole in a chlorophyll semiconductor. This statement rests on the following evidence: 1. In chromatophores of photosynthetic bacteria the chlorophyll shows, upon illumination, a reversible shift in every absorption band toward shorter wave lengths. 2. This shift is essentially the same from 300 to 1[degree]K. 3. The process responsible for this shift pre-cedes the operation of the enzymatic electron transport system. To the extent that enzymes can remove the primary excited electrons, the shift is diminished. 4. The sudden change in dielectric constant of dried chromatophores upon illumination shows that electrons and holes are spatially spatially separated.