FAT SYxNTHESIS 



393 



TABLE 36 CHANGES IN THE PROPORTIONS OF FATS AND CARBOHYDRATES IN THE KERNEL OF 



ALMOND SEEDS DURING MATURATION (dATA OF LE CLERC DU SABLON, 1 896) 



Date of collection 



June 9 



July 4 



August I . . . 

 September i 

 October 4. . 



Per cent 

 fat 



2 

 10 



37 

 44 

 46 



Per cent 

 glucose 



6 



4- 

 o 

 o 

 o 



Per cent 

 sucrose 



6.7 



4-9 

 2.8 

 2.6 



2-5 



Per cent starch 

 and dextrins 



21.6 



14. 1 



6.2 



5-4 

 5-3 



The preceding discussion indicates that there are three important steps 

 in the synthesis of fats in plants: (i) synthesis of glycerol, (2) synthesis of 

 fatty acids, and (3) condensation of fatty acids and glycerol resulting in 

 the formation of fats. 



I. Synthesis of Glycerol. — Glycerol is a heavy, colorless, viscous liquid 

 which is miscible with water in all proportions. Although the chemical 

 reactions by which glycerol is produced from carbohydrates in plant cells 

 are not known, it is not difficult to postulate how this process might take 

 place. Cleavage of a glucose molecule at the center of the carbon chain will 

 give rise to two molecules of glyceric aldehyde, thus: 



H 



H— C— OH 



( 

 H-C— OH 



Hj-C— OH 

 HO-C— H 

 H— C— OH 



H 

 H-C-OH 

 ^ 2 H-C-OH 



CHO 



Glyceric aldehyde 



CHO 



Glucose 

 Reduction of the glyceric aldehyde would result in the production of glyc- 

 erol : __ 



H H 



H-C-OH H-C-OH 



H-C-OH -1-2 H-» H-C-OH 



CHO H-i-OH 



Glyceric aldehyde H 



Glycerol 



