Final answer:
Cellulose is not used for energy storage; it serves as structural support in plant cell walls. Starch and glycogen are energy storage molecules in plants and animals, respectively, while glucose is a source of immediate energy.
Step-by-step explanation:
Among the listed carbohydrates, cellulose would not be a molecule used for energy storage by organisms. While starch and glycogen serve as energy storage molecules, cellulose is primarily used for structural support in the cell walls of plants. To elaborate, starch is the storage form of glucose in plants, used to store energy derived from photosynthesis. Glycogen is an animal equivalent, a highly branched polymer of glucose stored in liver and muscle cells to be broken down into glucose when needed. However, cellulose is composed of glucose monomers linked by ¹⁴ glycosidic bonds and unlike starch or glycogen, it is not easily digestible by most animals, making it unsuitable for energy storage. Instead, it provides rigidity and strength to the plant cell walls. Glucose, whilst being a monosaccharide, is a source of immediate energy rather than a storage form.