Primary Quantum Conversion in Photosynthesis

h e photoinduced elec6ron paramagnetic resonance s i g n a l s found i n photosynthetic t i s s u e a s a f u n c t i o n of wavelength, a s w e l l as temperature, have made p o s s i b l e a more p r e c i s e d e f i n i t i o n of t h e n a t u r e of t h e primary quantum conversion a c t , These o b s e r v a t i o n s , t a k e n t o g e t h e r w i t h new a s w e l l as o l d e r observations on t h e light-induced s p e c t r a l changes i n b o t h b a c t e r i a l chromatophores and green p l a n t quantasomes, have allowed ' u s t o s p e c i f y t h e p l a c e at which two d i s t i n c t and s e p a r a t e quantum convers i o n e l e c t r o n t r a n s f e r r e a c t i o n s occur i n green p l a n t s .The t r a n s f e r from a c h l o r o p h y l l aggregate t o an a c c e p t o r substance occurs s i m i l a r l y i n t h e green p l a n t s as w e l l as t h e b a c t e r i a l systems.The o t h e r a c t , t h e t r a n s f e r of an e l e c t r o n from a donor system producing a h i g h l y o x i d i z e d h o l e t o t h e c h l o r o p h y l l a g g r e g a t e , , i s l i m i t e d t o t h e green p l a n t .\ This l a t t e r , h i g h l y o x i d i z e d m a t e r i a l t h e n c o l l e c t s i t s e l e c t r o n s u l t i m a t e l y .with from w a t e r / t h e production of oxygen.I n t h e green p l a n t , t h e spread i n energy between t h e primary donor molecule i n t h e second a c t and t h e primary a c c e p t o r molecule of t h e f i r s t a c t may be as much a s 2 e v , providing f o r a t l e a s t t h r e e , and p o s s i b l y more, s i t e s f o r t h e production of ATP and f o r t h e spontaneous passage of h o l e s and of e l e c t r o n s from t h e s e primary donor and acceptor s i t e s , r e s p e c t i v e l y , t o t h e i r u l t i m a t e s i t e s i n molecular oxygen, on t h e one hand, and reduced p y r i d i n e nucleoti.deon t h e o t h e r .