210 COLLEGE BOTANY 



Protoplasm has the power of making new protoplasm and 

 practically all the other plant products found in the plant, such 

 as cell walls, sugars, starches^ fats, oils, resin and alkaloids, are 

 made either directly or indirectly from protoplasm. 



We will now turn our attention to some of these very com- 

 plex chemical activities of the plant. The first of these is 

 metabolism, which involves both constructive (anabolic) and de- 

 structive (catabolic) pTOcesses of growth. These processes in- 

 clude the breaking down of the true foods: carbohydrates, fats 

 and oils, and proteins, which have been manufactured by the 

 plant, and their utilization in the making of protoplasm, in the 

 growth of the plant, and the formation of the many plant prod- 

 ucts. Some of these products become permanent plant struc- 

 tures, others are temporary and for immediate use by the plant, 

 others are stored for future use, and others are apparently 

 by-products so far as their use by the plant is concerned and 

 may be thrown off or retained within the plant. 



Some of the most important of these metabolic products 

 are the protoplasm, sugars, starches, fats and fatty oils, pro- 

 teins, cellulose, cutin, suberin, lignin, volatile oils, glucosides, 

 acids, tannins, alkaloids, pigments and enzymes. Some of 

 these plant products are utilized by man and are of great com- 

 mercial value. 



The building up of the various parts of the plant is a con- 

 structive or anabolic process. But the constructive processes 

 cannot be carried on without the breaking down of existing 

 compounds which are to be used in construction and the repair 

 of a part of the machine which is doing the work ; that is, cata- 

 bolic processes. Therefore, the various activities of the plant, 

 s^ich as absorption of aqueous solutions, translocation of crude 



