What is the substance formed by a very large amylose chain?

The substance formed by a very large amylose chain is amylopectin. Amylose and amylopectin are both polysaccharides made from glucose units, and they are two types of starch.

Amylose consists of long, unbranched chains of glucose molecules linked together primarily by α(1→4) glycosidic bonds. In contrast, amylopectin is characterized by its branched structure, which is due to additional α(1→6) glycosidic bonds that occur at intervals along the chain. As a result, amylopectin typically has a larger and more complex structure than amylose.

The correct choice highlights the relationship between the configurations of amylopectin and amylose, emphasizing that the extensive chain of glucose units in amylose can contribute to the formation of the branched structure that defines amylopectin. Other options like glycogen, cellulose, and maltose represent different forms of carbohydrates or sugars, but they do not directly derive from very large amylose chains in the way that amylopectin does.