FRITZ LIPMANN 



The Energy Problem 



The recognition of the relative simplicity of the energy 

 supply system of the living organism has made it possible to 

 understand a large number of biosynthetic mechanisms (15). 

 We now feel justified to state with confidence that the energy 

 problem can be related to a boundary condition of the living 

 system as a whole and does not represent an intrinsic character- 

 istic of the life process except that it is a necessary premise for its 

 existence. The living organism is to be defined as a system with 

 a boundary condition of a constant influx of energy from the 

 outside. Such a system, however, in no way transcends the laws 

 of thermodynamics. In the past, a suspicion often crept in that 

 need might arise for a modification of the second law. Recently 

 a tendency developed to build into a definition of life the con- 

 cept of a negative entropy (20) which, however, is not a charac- 

 teristic of life but rather of the environmental conditions which 

 permitted life to develop. The earth is indeed, if isolated and 

 considered as a quasi-autonomous system, appropriately repre- 

 sented by including the incidental radiation energy as a boundary 

 condition, abstracting it, as we mostly tend to do anyway, from 

 the solar system and the universe. Although, in its elaboration of 

 metabolic work, the living organism acts in the capacity of a 

 refinery, the essential boundary condition almost always refers 

 back to the influx of energy from the outside into the earth 

 sphere. 



Patternization 



Much emphasis is generally placed on our recently ac- 

 quired capacity to understand the biochemical mechanisms for 

 building up structures such as steroids, carotenoids, and similar 

 complex molecules, which had previously been elucidated 

 through organic chemical analysis. Although these complex 

 molecules have their important significance for organismic life, 

 the most important problem is the problem of the building up of 

 specific and unique structures by fusing a number of otherwise 



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