SYNTHESIS OF PROTEIN 19 



suitable for utilisation than this (see Chaps, on Osmosis, Surface 

 Tension, etc.). 



Fats are stored up also in the plant. Very little research has 

 been done on the synthesis of fats in the plants. Whether the 

 plant can form these compounds directly or whether they are 

 only synthesised from carbohydrate is not known. That they 

 can be formed from carbohydrates is known, and Leathes states 

 that this action is exothermic, several molecules of simple sugar 

 going to the formation of one (larger) molecule of fat, having, of 

 course, a higher caloric value. The fat is almost exclusively 

 found in the fruit. 



Incidentally, energy is bound in the formation of proteins. 

 This energy comes indirectly from the sun. Atmospheric nitrogen 

 is fixed in a form available for plant use by certain bacteria. 

 Each gram of nitrogen so fixed carries with it a considerable 

 quantity of energy which is obtained from the oxidative decomposi- 

 tion of 100 mg. mannitol, the parent alcohol of the carbohydrate, 

 mannose. Moore and Webster have also shown that dilute 

 solutions of nitrates exposed to ultra-violet rays are converted into 

 nitrites with an absorption of energy. One gram molecule of 

 nitrite formed from nitrate transforms about 10,000 gram-calories 

 of radiant energy into the potential state — a strong endothermic 

 reaction. This is similar to the change taking place in the plant 

 in the formation of nitrogen compounds — the first stage in protein 

 anabolism. 



Baly suggests the following scheme as an indication of what 

 probably occurs in the plant. 



Potassium Nitrate Carbon-dioxide and Water 



Potassium Nitrite Formaldehyde 



(Formhydroxamic Acid) Carbohydrates 



I i 



Nitrogen Bases a Amino Acids 



Alkaloids and Xanthine derivatives Proteins 



To conclude, the plant acts as a transformer of kinetic into potential 

 energy by the formation of carbohydrates, fats, proteins {the so-called 



2—2 



