Question

What are carbohydrates ? Define small carbohydrates and discuss their types.

Answer 1

Carbohydrates are polyhydroxy aldoses or ketoses and their condensation products. These are compounds made up of carbon, hydrogen, and oxygen. with the general formula of C${}_n$H${}_{2n}$O${}_n$. These are two types, small and complex. Small carbo­hydrates have low molecular weight. They are also called as sugars. These are two types, monosaccharides, and oligosaccharides.

Monosaccharides are simple carbohydrate monomers. They cannot be further hydrolyzed. For example, glucose, galactose. These are building blocks of oligosaccharides and polysaccharides.

Oligosaccharides are simple carbohydrates made up of 2 to 9 monosaccharides. The monosaccharides are linked by glycosidic linkage. They belong to the category of compound carbohydrates. These are further divided into disaccharides, trisaccharides, tetrasaccharides, pentasaccharides, etc depending upon the number of monosac­charide molecules present into oligosaccharides. Examples of disaccha­rides are sucrose, lactose. Example of trisaccharides is raffinose. Example of tetrasaccharides is stachyose.