CARBOHYDRATES

1. Carbohydrate = hydrate of carbon.
2. Hydroxyl group present.
3. Aldehyde group or keto group may present.
4. Carbohydrates are polyhydroxy aldehydes or ketose.
5. Aldehyde group (-CHO) is generally terminal while keto group (> C = O) is commonly subterminal.
6. Depending upon the presence of aldehyde or keto group, carbohydrates are called aldoses are ketoses.
7. Carbohydrates contain Hydrogen and Oxygen in proportion as present in water.
8. There are few exceptions -

                 Acetic acid (C₂H₄O₂), Formeldehyde (CH₂O), Lactic acid (C₃H₆O₃)                         [Not Carbohydrate]
                 Deoxyribose sugar (C₅H₁₀O₄), Ranose (C₆H₁₂O₅), Glucosamine (C₆H₁₃ON)             [Carbohydrate]

1. Empirical formula is C_n(H₂O)_n or (CH₂O)_n.
2. Generally 3 elements present in carbohydrate as C, H & O.
3. Some carbohydrates contain Nitrogen, Phosphorus and Sulphur.
4. Carbohydrates are also named saccharides as they are formed of sugars.
5. Carbohydrates that are water soluble & sweet in taste are called sugars.
6. a & b - forms of sugar show isomerism.
7. The term sugar is used for small carbohydrates (monosaccharides and disaccharides) that are sweet to taste.
8. Carbohydrates are the first products of photosynthesis and the main ingredient of reserve food.
9. They are also called Staff of life.
10. Upto 80% of the dry weight of a plant is made of carbohydrates.
11. However, in an animal, the carbohydrate content is not more than 1% of the total.
12. Carbohydrates are of three types - Monosaccharides, Oligosaccharides, Polysaccharides