44 



J. D. BERNAL 



5. What was the first coherent metabolism of the sub-vital (mineral sup- 

 ported ?) indefinite areas ? 



6. What polymerized compounds stabilized the eobionts (coacervate drops) ? 



7. What were the first nucleoproteins ? Did RNA precede DNA in the bio- 

 poesis ? 



8. What is the origin of long-chain lipids ? What was contained in the first 

 lipid-covered vesicles (organelles)? 



9. What is the history of the nucleated cell ? 



Inorganic 

 Precursors 



Small 

 organic 

 molecules 



SH CH4 CO2 



Simple 

 carbonamides 

 Vegetable 

 acids and 

 alcohols 



Me(Feetc) {P02(0H2)} 



/inorganicl 



orthophosphate 



Phosphocyanate [P0(0H)2] n 



Metaphosphates 



Polymers Proteins ^!?r^'^ Nucleic = photosynthesis 



Fig. I. Scheme of organic molecular evolution 



Of these questions i, 2, 3, 4, 5, and 7 form a sequence in biochemical history 

 to which I have suggested answers in Fig. i. Questions 6, 8, and 9 form a sequence 

 in the history of intracellular structure. The relation of the two sequences need 

 not however be as indicated here or in Table i. 



To conclude, the purpose of this paper has been throughout not one of pro- 

 viding solutions to the problems of biopoesis but rather of formulating these 

 problems themselves and putting them in some framework of order. The 

 two chief tasks in the elaboration by many workers of a complete scheme of 

 biopoesis are first the establishment of more or less plausible connected areas of 

 development, those for instance of the origins of proteins or of photosynthesis, 

 and secondly the reasonable linking of these areas of knowledge into a coherent 

 whole. The first of these tasks has been much advanced in recent years, as witness 

 the many valuable contributions to this Symposium, but the second is only just 



