Significance of Carbohydrates:-

The carbohydrates perform the two important functions in living bodies:

(a) They act as bio fuels to provide energy for functioning of living organisms. In human system all the carbohydrates except cellulose can serve as source of energy. Starch and various sugars taken as food are first hydrolysed to glucose by the enzymes present in our digestive system.

2(C₆H₁₀O₅)_n + n H₂O n C₁₂H₂₂O₁₁

Starch                                                                   Maltose

C₁₂H₂₂O₁₁ + H₂O 2 C₆H₁₂O₆

Maltose                                               Glucose

Glucose on oxidation to carbon dioxide and water in presence of enzymes liberates energy to carry out various bodily functions:

C₆H₁₂O₆ + 6 O₂6 H₂O + 6 CO₂ + 2832 KJ

The carbohydrate Glycogen is stored in the liver which fulfills the emergency requirements of our body.

Cellulose cannot be hydrolysed in human (mono gastric) body because enzymes required for its hydrolysis are not present in human body. However, in grazing animals cellulolytic bacteria present in rumen break down cellulose with the help of enzyme cellulose to give glucose.

(b) They act as constituents of cell membrane.