Name: Important Sources of Vitamins
Uploaded: 2019-07-19
Duration: 2 min 57 s
Description: Vitamins are essential for several biochemical reactions and the development of the body. This video describes their sources, types based on their solubility...

Question

What is the difference between starch and glycogen?

Accepted Answer

Glucose is stored in the form of glycogen as a source of potential energy, readily available when needed. Glycogen is a polysaccharide found in all animal cells occurring mainly in muscles and the liver. Some are stored in the liver and the rest in muscles. When the blood sugar level is low, the liver changes glycogen back to glucose and only stores it for six hours. Muscle glycogen is used up by the muscle during muscular activity. Glycogen serves as a reserve carbohydrate of animals and is, therefore known as animal starch because of its structure similar to amylopectin but more branched than that. Glycogen is a polymer of about a thousand glucose units arranged in the form of a highly branched chain. When muscles, liver, and other body cells are saturated with glycogen, excess glucose is converted to fat and is stored as adipose tissue. Excess glucose is changed to glycogen in the liver. The whole process of formation of glycogen is known as glycogenesis.

Starch is the main storage polysaccharide of plants. It is also known as amylum with the general formula ${(C_{6} H_{10} O_{5})}_{n}$ . It is a non-reducing sugar and is not readily oxidize as reducing sugar. Therefore, it is more useful for preserving foods such as jams, jellies, etc. It is a polymer of $α$ -glucose. The high content of starch is found in cereals, roots, rubbers, and some vegetables. It is hydrolyzed to glucose by enzyme amylase(present in saliva). It mainly contains two components- amylose $(15 - 20 %)$ and amylopectin $(80 - 85 %)$ . Amylose is the linear polymer of $α - D - glucose$ whereas, amylopectin is a highly branched chain polymer of $α - D - glucose$ .

Therefore, glycogen is the energy storage carbohydrate that is found mainly in animals and fungi whereas starch is the energy storage carbohydrate that is found predominantly in plants. Glycogen is made up of the single-molecule whereas starch is made up of two molecules namely amylose and amylopectin.

What is the difference between starch and glycogen?

Important Questions on Biomolecules

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