Final answer:
Glucose, starch, and cellulose are all carbohydrates composed of glucose units. Starch (made of amylose and amylopectin) is an energy storage in plants, while cellulose is a structural component with a linear chain of glucose molecules.
Step-by-step explanation:
Glucose, starch, and cellulose are all carbohydrates that play crucial roles in biology. They are different forms of polysaccharides; however, they share some common characteristics. The most notable commonality is that they consist of glucose units. Glucose itself is a simple sugar or monosaccharide that serves as a building block for both starch and cellulose. Starch, primarily found in plants, is a storage form of energy and is composed of two types of glucose polymers: amylose (linear) and amylopectin (branched).
On the other hand, cellulose is a structural polysaccharide found in cell walls of plants, characterized by a linear chain of glucose molecules linked through ß-1,4-glycosidic bonds. Despite their shared glucose composition, starch and cellulose possess distinct structures and functions within biological systems. Enzymatic differences between the metabolism of starch and cellulose explain why humans can readily digest starch for energy but are unable to digest cellulose.