n THE ORGANISM AS AN OPEN SYSTEM I5I 



which require the highest input of energy (formation of dipeptides) take place in 

 the mitochondria which, containing the cyclophorase and phosphorylation 

 systems, can provide this amount of energy by oxidative or fermentative processes, 

 energy being stored in high-energy phosphate bonds which are transferred to 

 amino acids ; the subsequent formation of long chains which, for thermodynamic 

 reasons, requires less energy, takes place in the microsomes, the RNA of which 

 may act as template. 



{/) Energy requirements of the maintenance of the steady state of the organism 



The maintenance of the body proteins in a steady state distant from equilibrium I 

 and maintained in continuous degradation and regeneration requires energy, I 

 Even the cell not performing external work needs continuous import of energy . . 

 as shown by the fact that under lack of oxygen all vital functions of an (aerobic) [l 

 cell cease. The maintenance work of the cell is partly physicochemical such as 

 maintenance of structures, of osmotic pressure, ion concentrations, etc., different 

 from equilibrium; partly it is chemical, that is, maintenance of the body compo- 

 nents in a steady state distant from chemical equilibrium {i.e., for proteins, 

 practically complete dissociation into amino acids). These energy requirements 

 can be calculated (Bertalanffy, 1942a; G. V. Schulz, 1950; BertalanfTy, 1953). 

 Starting from the Van 't Hoff equation for the work necessary to bring i mole of a 

 substance from the equilibrium concentration c* to another concentration c: 



A = RTln {cic*) (2.13) 



some calculations lead to the approximative formula : 



dajdt = r- 93 cal/g protein (2.14) 



for the maintenance work of the organism, assuming an average polymerization 

 P = 1000 for proteins, an average molecular weight of 100 for animo acids, and 

 r being the turnover rate per day. Inserting the values known from isotope 

 experiments (Table i), it appears, somewhat surprisingly, that only about i to 2 | 

 per cent of basal metabolic rate of an adult human or rat are rec^uired for the J 

 maintenance of proteins in a steady state. Estimates from protein metabolism with 

 somewhat diflferent assumptions (Borsook, 1950) and from the duplication of the 

 number of cells in regenerating rat liver (Lang, 1952) lead to a similar result. 



(g) Thermodynamics of open systems 



As already mentioned, the apparent gulf between inanimate and living nature 

 with respect to the second principle of thermodynamics has embarrassed physicists 

 and philosophers for a long time. For example, the American philosopher and 

 historian, Henry Adams (1920), pointed out what he called "the violent contra- 

 diction between Lord Kelvin's degradation and Darwin's elevation, between the 

 law of dissipation in physics and the law of evolution in biology". According to 1 

 the second principle of thermodynamics, the general trend of physical events is 1 

 toward states of increasing disorder and leveling down of differences. High forms • 

 of energy are irreversibly degraded to heat and heat gradients progressively 

 disappear. In this way the universe "runs down" and eventually approaches heat 



Literature p. 253 



