Here's why:
* Glycogen is a highly branched polymer of glucose that serves as the primary energy storage molecule in animals. It's stored in the cytoplasm of liver and muscle cells, and can be broken down quickly to provide glucose for energy.
* Starch is also a polymer of glucose, but it's less branched than glycogen. It's the primary energy storage molecule in plants, and it's stored in the cytoplasm of plant cells, particularly in the form of granules.
While other storage compounds exist in the cytoplasm, like lipids (fats) and proteins, glycogen and starch are the major ones, responsible for storing carbohydrates.
