Starch is a polysaccharide produced by most green plants as energy storage. It's composed of glucose units connected by glycosidic bonds.
Amylose: This is one component of starch and consists of unbranched chains of glucose molecules connected by alpha-1,4-glycosidic bonds.
Amylopectin: The other component of starch; it has branched chains with both alpha-1,4 and alpha-1,6-glycosidic bonds between glucose units.
The basic unit that makes up starch; it's like the individual energy units stored in your phone's battery.