OPENING ADDRESS 



II Reduction 



Hexoje 



EI Back-Reoction / 



Photo-Phosphorylofion ITPN 



Fact, 



i 

 H,0 



3ZI Dehydrogenotion 

 Photoxydotion 



H,A 



H--,H-S;S;Asc.A.;RH, 



Hq Substitute Reductions 



COp + RH— RCOOH— RCO 



Dye 



Dye H2 



Quinone — *• Hydroqumone 



Flavin *■ Flavin H2 



Cyt.c^* — ► Cyt.c^* 



02 ► H2O2 



TPN * TPN(HJ 



1 r"^ 



nz Chlorophyll 

 complex 



■ XHg *-XH-^Chl. al X > 685 m/-( 



roH ^\ 



~ P \\ . Accessory Pigments 



— -;(0H)-— YOH —Chi. a.E X < 685 m/u 



Fig. 1. Sum of the recognized partial enzymatic systems which together con- 

 stitute the mechanics of photosynthesis. All except the chlorophyll complex are 

 able to function without light. 



and oxygen play in the corresponding ordinary dark metabolism. Thus 

 a cell-free system can be set up which converts light energy into 

 typical phosphate energy: ATP, The experiment works with green or 

 purple chromatophores— there is no difference, 6) Identical or very 

 similar enzymes serve as reducing agents for the carbon dioxide re- 

 duction system and for the initial carboxylation, 7) Photosynthetic 

 units exist in both types of organisms, according to Arnold's experi- 

 ments. This implies at least two differently bound molecules of the 

 same pigment class in bacteria just as well as inplants: the photon- 

 collecting and the photon- converting molecules of which the latter, 

 according to Franck, must have its main absorption at the long wave- 

 length end of the complex spectrum shown by living chlorophyll, 

 8) Transfer of energy from light-absorbing accessory pigments happens 

 in both classes of organisms. To these eight points others equally 

 important may soon be added. In short, there is so much in common 

 that the problem of utilization of water as hydrogen donor might better 



