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Outline the classification of carbohydrates giving example for each.(OR) How are carbohydrates classified? |
Answer» Solution :Carbohydrates are polyhydroxy aldehydes or polyhydroxy ketones. The carbohydrates may be summarised as below.  (i) Sugar : They are sweet crystalline substance and soluble in water. (a) Monosaccharides : They are polyhydroxy aldehydes (or) polyhydroxy ketones. Aldoses - Carbohydrates containing aldehyde group. Eg: Glucose Ketoses - Carbohydrates containing ketone group. Eg: Fructose. (B) Oligosaccharides : They are sugars that yield two to ten monosaccharide molecules on hydrolysis. Disaccharides : They are sugars which on hydrolysis give two molecules of same or different monosaccharides. Eg: Sucrose, maltose. `underset("Sucrose")(C_(12)H_(22))O_(11)+H_(2)Orarrunderset("Glucose")(C_(6)H_(12)O_(6))+underset("Fructose")(C_(6)H_(12)O_(6))` Trisaccharidcs: They are sugars which gives there molecucules of monosaccharides on hydrolysis Eg: Raffinose. `underset("Raffinose")(C_(18)H_(32)O_(16))+2H_(2)Orarrunderset("GALACTOSE")(C_(6)H_(12)O_(6))+underset("Glucose")(C_(6)H_(12)O_(6))+underset("Fructose")(C_(6)H_(12)O_(6))` (ii) Non-sugars (or) Polysaccharides: They are non-sugars which involve a large number of monosaccharide units linked to each other by OXIDE bridges. These bridges are called glycosidic linkages. Eg: starch, cellulose. `underset("Starch")(C_6H_10O_5)+nH_(2)Ooverset(H^(+))rarrunderset("Glucose")(nC_(6)H_(12)O_(6))` |
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