What is Carbohydrates

What is carbohydrates:- Hello friends welcome to yourstudynotes.com today topic is carbohydrates. I hope this topic is very help full in your study.so let’s start.


carbohydrates are very important organic compound made of carbon, hydrogen and oxygen carbohydrates are abundantly present in plant materials like starch, sugar, glucose and cellulose etc. They have the same ratio of hydrogen and oxygen as in water therefore they are called hydrates of carbon and represented by the general formula Cx(H2O)y

But now it is believed that carbohydrates like ramnose C6H12O5 and Ramnohexose C7H14O6 do not have 2:1 ratio of hydrogen and oxygen . In contrast compounds like formaldehyde CH2O, acetic acid C2H4O2 and latic acid C3H6O3do not belong to carbohydrate category but they too have 2:1 ratio of hydrogen and oxygen. Therefore it is not appropriate to use the word hydrates of carbon for carbohydrates. Now a days the world carbohydrates is used for polyhdroxyketones or polyhydroxy-aldehydes or those substance which produce such compound on hydrolysis, like cellulose , starch , glycogen etc. 

In nature green plants make carbohydrates with the help of raw materials like carbon dioxide and water in the presence of chlorophyll and sunlight by the process of photosynthesis.

6CO2 +12H2→C6H12O6 + 6O2 + 6H2O

Classification of carbohydrates:-

on the basis of their physical properties,  are classified into following two groups:-

  1. Sugars:-

Sugars are crystalline substance soluble in water and sweet in taste like glucose, fructose, cane sugar.

2. Non sugars:-

These are non crystalline, water in soluble substance, which are not sweet in taste, like starch, cellulose etc.

On the basis of chemical composition the carbohydrates are classified into following three groups:-

  1. Monosaccharides:-

Monosaccharides are simplest colourless carbohydrates which are sweet in test and soluble in water. They are sparingly soluble in alcohol but insoluble in benzene and ether. There are two types of monosaccharides



2. Oligosaccharides:-

Oligosaccharides are made by the combination of two to ten same or different monosaccharide molecules . During this Process water molecules are released. This Process is called Condensation. Monosaccharide unit are joined in it through oxygen bridge called glycosidic bond. Oligosaccharides are crystalline sweet in taste and soluble in water.

3.  Polysaccharides:-

Polysaccharides are forms by the condensation of many form even to thousand monosaccharide unit joined by glycosidic bonds. This Process is called Polymerisation. on Hydrolysis Polysaccharides produce monosaccharide unit . Polysaccharides are non crystalline tasteless compounds insoluble in water. Polysaccharides made of same type of monosaccharides are calles homopolysaccharides while heteropolysaccharides made of different types of monosaccharides units. some common Polysaccharides found in nature  are

  • Starch

  • Cellulose

  • Glycogen

  • Pectin

  • Chitin

Funcation of carbohydrates:-

  1. Glucose acts as source of energy in our body.
  2. Glycogen is stored in muscles and liver as a source of stored energy.
  3. In Plants the cell wall is made of cellulose.
  4. Polysaccharide form structural components of connective tissue.

Sources of carbohydrates:-

Glucose is the main source of energy of animal. Animal derive it from sugars and starch cereals, roots and tubers are the main source of starch. Apart from this sucrose is obtained from sugar cane, maltose from germinated seeds and lactose from milk.