Glycogen for internal use and is not shared with other cells. This is in contrast to liver cells, which, on demand, readily do break down their stored glycogen into glucose and send it through the blood stream as fuel for other organs. Glycogen was discovered by Claude Bernard. His experiments showed that the liver contained a substance that could give rise to reducing sugar by the action of a "ferment" in the liver. By 1857, he described the isolation of a substance he called ""la matière glycogène"", or "sugar-forming substance". Soon after the discovery of glycogen in the liver, A. Sanson
Glucose of consumed food. Organisms use glucose as a precursor for the synthesis of several important substances. Starch, cellulose, and glycogen ("animal starch") are common glucose polymers (polysaccharides). Some of these polymers (starch or glycogen) serve as energy stores, while others (cellulose and chitin, which is made from a derivative of glucose) have structural roles. Oligosaccharides of glucose combined with other sugars serve as important energy stores. These include lactose, the predominant sugar in milk, which is a glucose-galactose disaccharide, and sucrose, another disaccharide which is composed of glucose and fructose. Glucose is also added onto certain proteins and lipids in