- Starch is the primary storage carbohydrate in plants. It is stored in plastids (like chloroplasts and amyloplasts) and is the main form of carbohydrate consumed by humans from plant sources (e.g., grains, potatoes). - Glycogen is the primary storage carbohydrate in animals and fungi. In animals, it is primarily stored in the liver and muscles, where it can be quickly mobilized to provide glucose for energy. Therefore, starch is characteristic of plant cells, while glycogen is characteristic of animal cells.