What is the primary difference between glycogen and cellulose?

The primary difference between glycogen and cellulose lies in their functions and structures. Glycogen is a polysaccharide that serves as a primary form of energy storage in animals, particularly within the liver and muscles. It is composed of glucose units linked together in a branched structure, which makes it readily accessible for energy when needed.

In contrast, cellulose is also a polysaccharide but functions primarily as a structural component in the cell walls of plants. It is composed of long, unbranched chains of glucose units linked together in a way that provides rigidity and support to plant cells. This structural role is crucial for maintaining the integrity and shape of plants.

The other provided choices do not accurately reflect the true relationship between glycogen and cellulose. Glycogen is not a protein or a lipid, nor does it contain nucleotides; it specifically consists of glucosidic linkages of glucose. Additionally, cellulose is primarily found in plants, while glycogen is stored in animals, not the other way around. Thus, the distinction of glycogen serving as an energy storage molecule and cellulose as a structural component is what makes the first statement correct.