What is the difference between starch and glycogen, and how do they function in energy storage?

Starch and glycogen are both polysaccharides used for energy storage, but they differ in structure and function.

Starch is a complex carbohydrate found in plants, consisting of two types of glucose polymers: amylose and amylopectin. Amylose is a linear chain of glucose molecules, while amylopectin is branched. Starch is stored in plant cells as granules, which can be broken down by enzymes to release glucose for energy. Humans and animals can also digest starch, breaking it down into glucose for energy. For more on enzyme functions in biological processes, refer to enzymes as biological catalysts. Humans and animals can also digest starch, breaking it down into glucose for energy.

Glycogen, on the other hand, is the animal equivalent of starch. It is a highly branched polysaccharide made up of glucose molecules. Glycogen is stored in the liver and muscles, where it can be broken down into glucose for energy when needed. Unlike starch, glycogen is not found in plant cells. The process of glycolysis and ATP production is essential in converting glucose from glycogen into usable energy.

Both starch and glycogen are important for energy storage in their respective organisms. They allow for a steady supply of glucose to be released into the bloodstream as needed, providing energy for cellular processes. The testing of these biological molecules can be explored further in testing for biological molecules. However, the structures of starch and glycogen are adapted to the needs of their respective organisms. Starch is optimised for storage in plant cells, while glycogen is optimised for storage in animal cells. For a deeper understanding of their molecular structure, see DNA structure.

A-Level Biology Tutor Summary: Starch and glycogen are polysaccharides that store energy. Starch, found in plants, consists of amylose and amylopectin, and is stored as granules. Glycogen, found in animals, is highly branched and stored in the liver and muscles. Both release glucose for energy, with structures adapted to their specific storage needs in plants and animals.