50 



The Chemistry of the Injured Cell 



important of these compounds. The process is known as electron 

 transport and occurs in a stepwise fashion, the final step being the 

 transport of electrons from cytochrome to oxygen. In the process the 

 cytochrome, of course, becomes oxidised and thus becomes avail- 

 able for further service as a hydrogen carrier (Fig. 3) . 



Oxaloacetate 

 Succinate <4r 

 etc. 



Isoci 



Irate 



2H 



T 



DPN 



1 



I malate 



■oc "ketoglutarate 



etc. 



— 2H->TPN 



2H 



->Flavoprotein 



Succinate 



otltetoglutarate 



2H 



Cytochrome c^-[2| — Cytochrome b-«-[2H] — 



T 



Cytochrome Oxidase 



Fuma rate 



2H 



J 



Oxygen 

 Fig. 3. The Electron Transport Chain. 



The supply of energy is generated in the following manner 

 (Baldwin, 1957) . It is convenient to take glucose as a starting point 

 (Fig. 4) . The sugar is phosphorylated and converted to triose phos- 

 phate. This substance is then broken down to phosphoglyceric acid 

 with the liberation of energy which is stored as an energy-rich 

 phosphate bond in the molecule of ATP. Phosphoglyceric acid is 

 then converted to pyruvate with the liberation of another parcel of 

 energy, also stored in the ATP molecule. This is glycolysis. There 

 exists an alternative pathway for the breakdown of glucose termed 



