STARCH -

1. Polymer of a-D-glucose.
2. Starch is glucosan homopolysaccharide which is the major reserve food of plants.
3. Starch is formed as an end product of photosynthesis.
4. It is stored in the form of microscopic grains in chloroplasts and amyloplasts .
5. A molecules of starchy consists of two components, an inner core of amylose and an outer coat of amylopectin.
6. Amylose branch consists of 200-2000 units of a-D-glucose. It is a linear molecule which produces blue colour with iodine. Starch of potato has 20% amylose.
7. Amylopectin branch consists of 2000-200000 units of a-D-glucose. It is highly branched molecule which produces purple colour with iodine. It forms 80% part of starch of potato.
8. Starch is reserve food of plants while glycogen (animal starch) is reserve food of animals fungi and bacteria.
9. Peramylon is a form of starch stored in Euglena.