ENERGY TRANSFORMATION 423 



III. Intramolecular respiration "fermentation" 



Urea (to ammonia) 



Glucose (to acetic acid-anaerobic). 



Glucose (to alcohol) 



Glucose (to lactic acid) 



Glucose (to butyric acid) 



Acetic acid (to methane) 



Energy transformation in synthetic processes. The energy transfor- 

 mation in the synthetic action of microorganisms depends upon the 

 nature of the organism and of the substances present as nutrients. 

 The autotrophic bacteria and algae build up their carbohydrates from 

 the C0 2 ; this phenomenon is one of reduction and involves, therefore, 

 a great expenditure of energy. 



6 C0 2 + 6 H 2 = C 6 Hi 2 6 + 6 2 - 676 Cal. 



This energy is obtained from the oxidation of ammonia, nitrous acid, 

 thiosulfate, sulfur, etc. (and, in the case of algae, photosynthetically). 

 Because of the large amount of energy required for synthetic purposes 

 and since work in the true sense is to be produced, large quantities of 

 these substances have to be oxidized. 



When carbohydrates are synthesized from organic compounds or, 

 in general, when an organism grows in a medium containing organic 

 substances as sources of energy, much less energy is consumed in the 

 synthesis of the protoplasm, as seen by reversing several of the above 

 reactions. 



3 C 2 H 4 2 = C 6 H, 2 0« - 44 Cal. 

 2 C 3 H 6 03 = C 6 H 12 6 - 2S Cal. 



The energy required in this case is obtained by aerobic microor- 

 ganisms from oxidation processes and by anaerobic bacteria by means 

 of "fermentations" or reactions of oxidation-reduction. The pro- 

 duction of polysaccharides from the monosaccharide requires only a 

 small expenditure of energy. 



2 C 6 Hi 2 6 - H 2 = CijH 22 0,i - 3.3 Cal. 

 n(C 6 H 13 6 ) - H 2 = (C 8 HioOo)n - (4.3 Cal.)n 



The building up of fats from carbohydrates or glycerol is a reduc- 

 tion phenomenon, it involves work in the thermodynamic sense and 

 requires a large expenditure of energy. This can, therefore, take 



