BIOLOGICAL ORDER 

 AND ENTROPY 



Sources of Energy 



An organism is a maciiine. In order to operate, 

 a machine has to be fed something, for example coal. It is not coal, 

 however, that causes the steam engine to operate, but the combustion 

 of coal. 



The living machine, in order to operate, must also be fed. It needs 

 energy. When the organism possesses chlorophyll, the source of 

 energy is light. When the organism is devoid of chlorophyll, the 

 energy is provided by the chemical bonds of the food. The organism, 

 in this case, burns more-or-less complex substances: organic com- 

 pounds such as sugars or amino acids, or mineral compounds such 

 as hydrogen sulfide, carbon monoxide, or even hydrogen. 



The organism performs oxidoreductions. The general equation 

 may be written: 



AHo -f B — ^ A + BHo 



hydrogen donor hydrogen acceptor oxidized reduced 



(reduced state) (oxidized state) donor acceptor 



If, for example, the hydrogen acceptor is oxygen, the reaction is 



AH2 + /z Oo — > A + HoO 



This is respiration. 



Aietabolism and syntheses consist essentially in the mobilization 

 of the energy of the chemical bonds of the food. Max Delbriick has 

 described an organism as a system of flux equilibrium which takes 

 matter and energy from its environment. 



[87] 



