INTRODUCTION 

 CARBOHYDRATE 



® 



OHoC 



/CH,0@ 

 h\h HOy/^QH 



HO H 

 11 

 2CH20(p).CHOH.CHO 



+4H-2H3PO4 % -4H+2H3PO, 

 2ADP+2CH20@.CH0H.C00(P) 



t t 



2ATP+2CH20(P).CH0H.C00H 



FRUCTOFURANOSE-I : 6- 

 DIPHOSPHATE 



3-PHOSPHO- 



GLYCERALDEHYDE 



I : 3-PHOSPHOGLYCERIC 



ACID 



3-PHOSPHOGLYCERIC ACID 



1 



..^pN 



2CH20H.CHO(^.COOH 2-phosphoglyceric acid 



+ 2H,0 % -2H2O 



2ADP+2CH2:C0(P).C00H 



t t 



2ATP+2CH3.CO.COOH 



phospho-enolpyruyic 



ACID 

 PYRUVIC ACID 



FIG. I. Scheme summarizing the reactions of glycolysis. For sim- 

 plicity certain reactions have been omitted. (p\ denotes the 



phosphate group, ADP, adenosine diphosphate, and ATP, 

 adenosine triphosphate (for further information see ref. 19). 



acid is completely oxidized to give carbon dioxide and 

 water by means of the system, represented rn Fig. 2, known 

 as the Krebs or tricarboxylic acid cycle.^^ This, or some 

 similar system involving di-carboxylic acids, is generally 

 assumed to occur in all aerobic organisms. Certain of the 

 acids concerned have been shown to take part in the meta- 

 bolism of Chlorella and Scenedesmus^^ and also to serve as 

 substrates for respiration in Chlorella,^^ Ulva, Myelophycus 

 and Gelidium}^^ Cell-free extracts of Chlorella have been 

 found to contain dehydrogenases for these acids, which are 



