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GENERAL PHYSIOLOGY 



cell the result is either one or the other, and organisms may 

 be classed as anabolic organisms or as catabolic organisms. 

 The anabolic organisms are the green plants and the proto- 

 trophic bacteria. The catabolic organisms are the animals, 

 fungi, metatrophic and paratrophic bacteria. These different 



FIG. 42. Illustrating Metabolism. The square represents a cell. A B repre- 

 sents food entering the cell. BC represents anabolism. CD represents 

 catabolism. BCD represents metabolism. DE represents the products 

 of metabolism, ab represents food of simple composition, de represents 

 complex by-products. An organism producing synthetic changes, indicated by 

 the line ae is called an anabolic organism. An organism producing the ana- 

 lytic changes, indicated by the line a'b'Cd'e' or a'e' is called a catabolic 

 organism. 



classes of organisms are of mutual aid to each other in the 

 universe. The anabolic organisms build up the food material 

 from simple sources into a form that is available for the cata- 

 bolic organisms. These, in turn, tear down the complex 

 organic matter and return it to the earth in a simple form 

 ready to be again taken up by the anabolic organisms. 



Respiration. Food is necessary to sustain life but food 

 alone will not enable life to go on. Food consumed repre- 

 sents a source or supply of energy, but this is not available 

 until it is oxidized and the potential energy locked up in the 

 food consumed is transformed into the kinetic energy of work. 



