10. Which of the following descriptions about starch synthesis is wrong? (A) Starch consists of the two glucose polymers, amylopectin and amylose, (B) starch is synthesized in the plastids, (C) the synthesis of ADP-glucose is often regarded as the "committed step" of starch synthesis, (D) starch is a non-structural carbohydrate, composed of glucose polymers linked by B- (1,4)-glycosidic bonds, (E) none of the above.