Insulin is a hormone that is protein in nature. It consists of two polypeptide chains. It is produced from pancreas that is both exocrine and endocrine gland.
It acts on the cells of the body and promotes the uptake of glucose from blood plasma hence leading to more glycolysis. Another function of insulin is it promotes the conversion of glucose to glycogen that is the storage form of carbohydrates in animals which they utilise when glucose intake is less than required.