CATALYSIS: THE GUIDE OF LIFE 109 



ester bond energy, the main form or source of anaerobic energy as 

 illustrated by the reaction: 



Glycerophosphate + H 2 0±^Glycerol + phosphate -f energy 



. . . The phosphate group also catalyzes the oxidation and trans- 

 port of fats. Other inorganic elements may participate in the 

 oxidation of fat and perhaps its transformation into carbohydrate. 

 Most electron donors (metabolites) must be phosphorylated as the 

 preliminary step; for phosphorylation and oxidation are indeed 

 coupled reactions." 



Broadly, then, a "coupled" reaction is one so closely associated 

 with another reaction as to determine the latter by providing the 

 necessary energy. While it is conceivable that in some cases the 

 total energy may be transferred without loss from one molecular 

 grouping to another, it seems reasonable to believe that the kinetic 

 aspects above outlined must generally be taken into account. 



Furthermore, living things do not depend upon any one type of 

 chemical change, the oxidation of glucose, though this is most im- 

 portant in so many plants and animals, including humans. The 

 autotrophic bacteria utilize the energy available in some common 

 exothermic reactions. 25 The "steaming" of manure piles and com- 

 post heaps is well known, and farmers sometimes use fresh manure as 

 an "anti-freeze," as well as in hotbeds. Prof. J. M. Nelson of Columbia 

 University informs me that in the early days in the Middle West, 

 farmers often kept their sod-houses warm by a thick layer of fresh 

 manure at the ground level. 



Quite a number of biological reactions can take place in the dark; 

 but in the synthesis of glucose by plants, solar energy is absorbed, 

 with a local decrease in entropy. Animals are directly or indirectly 

 dependent upon the glucose and other products synthesized by plants; 

 in fact, most living things depend upon the catalyzed chemical output 

 of others, and we are only beginning to understand these often curious 

 and multiple relationships. 



The Time Factor in Catalysis 



The catalysts used in industry are sometimes aggregated col- 

 loids (e.g., platinum sponge, nickel used in hydrogenation); but 

 generally they are extended on carriers. This not only exposes a 

 large active surface, but it also permits the finely divided catalyst 

 to remain in place when gases or liquids are passed over it, and 

 to be filtered off if it has been mixed into a batch. 



Some biocatalysts are fixed, like genes in the chromosomes; but 



