Final answer:
The incorrect statement about glycogen's structure is that it is a copolymer of glucose and mannose. Glycogen is a polysaccharide made of glucose units with alpha-1,4 and alpha-1,6 glycosidic linkages, and it is more highly branched than amylopectin.
Step-by-step explanation:
The structure of glycogen is indeed complex, but among the statements provided, the incorrect one is B. It is a copolymer of glucose and mannose. In actuality, glycogen is a polysaccharide consisting of D-glucose units connected primarily by α-1,4-glycosidic linkages with branching points through α-1,6-glycosidic linkages. These branches occur more often in glycogen than in amylopectin, typically at intervals of every 10 to 15 glucose units. Moreover, glycogen is highly branched, which makes it more soluble in water and facilitates rapid release of glucose when needed by the body, distinguishing it from the structure of starch (amylopectin and amylose).