Starch
- It is found in fruits, grains, seeds and tubers.
- It is the main source of carbohydrates for animals.
- On hydrolysis, it yields glucose molecules.
- It gives blue colour with iodine.
- It occurs in two types;
- Amylose starches have unbranched chains of glucose and are soluble in hot water.
- Amylopectin starches have branched chains and are insoluble in hot or cold water.
Polysaccharides are polymers of monosaccharides
(ii) Glycogen
- It is also called animal starch It is the chief form of carbohydrate stored in animal body.
- Found abundantly found in liver and muscles, though found in all animal cells.
- It is insoluble in water.
- It gives red colour with iodine solution.
- It also yields glucose on hydrolysis.
(iii) Cellulose
- It is the most abundant carbohydrate in nature.
- It is the main constituent of cell walls of plants and is highly insoluble in water. Cotton is the pure form of cellulose.
- On hydrolysis, it also yields glucose molecules.
- It gives no colour to iodine solution.
- It is not digested by human digestive tract. In the herbivores, it is digested because of microorganisms (bacteria, yeasts, protozoa) in their digestive tract. These microorganisms secrete an enzyme called cellulase for its digestion.
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