Glycogen is a branched polymer of glucose. Glucose residues are linked linearly by Alpha $\alpha -1,4 $ glycosidic bonds, and approximately every ten residues a chain of glucose residues branches off via $\alpha -1,6$ glycosidic linkages.
Glycogen is a multibranched polysaccharide of glucose that serves as a form of energy storage in animals, fungi, and bacteria.
Glycogen is a highly branched polysaccharide of glucose which is structurally similar to amylopectin. This high branching serves as the instant energy source for animals and some fungi.