These are defined as, optically active polyhydroxy aldehydes or ketones or the compounds which on hydrolysis give these units. They are also called saccharides.
e.g. glucose (C6H12O6) fructose, etc.
On the basis of the behaviour toward hydrolysis carbohydrates are broadly classified into following three classes:
Monosaccharides : These are the simplest carbohydrates which can not be hydrolysed to simpler molecules. They are further sub-divided into tetroses, pentoses or hexoses depending upon the number of carbon atoms.
Oligosaccharides : On hydrolysis, they generally give two to nine monosaccharides and are further classified as di, tri, tetrasaccharides.
e.g. sucrose, maltose, lactose.
Polysaccharides : These are polymers of monosaccharides.
e.g. starch, cellulose, glycogen, etc.
