Which polysaccharide is composed of long chains of glucose and can be classified into amylose and amylopectin?

Starch is a polysaccharide that serves as a crucial energy storage material in plants and is comprised of long chains of glucose molecules. It can indeed be divided into two distinct forms: amylose and amylopectin.

Amylose consists of long, unbranched chains of glucose molecules connected by alpha-1,4 glycosidic bonds. This structure allows it to form a helical shape, which is less soluble in water. On the other hand, amylopectin is a highly branched molecule made up of both alpha-1,4 and alpha-1,6 glycosidic bonds, providing it with a more complex structure that is more soluble in water. The branching in amylopectin allows for quicker access to glucose units, making starch an efficient energy reserve.

This characteristic of starch is essential for plant energy storage and equally important as a dietary source of carbohydrates for humans and other animals. The other choices, such as cellulose, glycogen, and chitin, involve different types of carbohydrate structures and functions, focusing on structural purposes or animal energy storage rather than the specific combination of glucose chains that defines starch.