CHAPTER V. 

 THE CARBOHYDRATES. 



There are several groups of these compounds, only a 

 few of which, however, are of any physiological importance. 



A. The Monosaccharides, or Simple Sugars. 



B. The Compound Sugars (Di- and Tri-saccharides). 



C. The Polysaccharides. 



The first two groups are colourless, crystalline substances, 

 readily soluble in water, and usually of a sweet taste. The 

 polysaccharides are mostly amorphous, insoluble in water, 

 and without a sweet taste. 



A. The Monosaccharides. 



A simple sugar is an aldehyde, or ketone, linked 

 directly to at least one alcoholic group. 



Sugars containing the aldehyde group are known as 

 aldoses, which therefore contain 



H C O H 



H C = O 



as a characteristic group. 



Sugars containing the ketone group are known as 

 ketoses, of which the group 



H-i 



: o H 

 = o 



is characteristic. 



