Which monosaccharide is the reducing end in maltose but the non-reducing end in cellobiose?
Correct: A
Maltose consists of two alpha-D-glucose linked by alpha(1->4), leaving one glucose free to act as a reducing agent. Cellobiose is beta-1,4 linked, and both hydroxyl groups remain occupied, making them non-reducing. The key distinction lies in the glycosidic linkage. Option A and B clarify alpha vs beta linkages, with A being correct for maltose.