Storage polysaccharide

Storage polysaccharides are complex carbohydrates that serve as the primary storage form of energy in many organisms. They are long chains of monosaccharides linked by glycosidic bonds. The two most common types of storage polysaccharides are starch in plants and glycogen in animals.

Structure and Function

Storage polysaccharides are made up of hundreds or even thousands of monosaccharides. They are typically unbranched or only slightly branched, allowing them to pack tightly and store a large amount of energy in a small space. The structure of storage polysaccharides also makes them insoluble in water, which prevents them from affecting the osmotic balance of the cell.

The primary function of storage polysaccharides is to provide a readily available source of energy. When energy is needed, enzymes break the glycosidic bonds, releasing the monosaccharides. These can then be metabolized to produce ATP, the cell's main energy currency.

Types of Storage Polysaccharides

Starch

Starch is the primary storage polysaccharide in plants. It is made up 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 plastids, such as chloroplasts and amyloplasts.

Glycogen

Glycogen is the storage polysaccharide in animals. It is similar in structure to amylopectin but is more highly branched. Glycogen is stored primarily in the liver and muscles, where it can be quickly mobilized to meet the energy needs of the body.

See Also

• Carbohydrate
• Monosaccharide
• Glycosidic bond
• ATP
• Amylose
• Amylopectin
• Chloroplast
• Amyloplast