α vs. β glycosidic linkages: starch vs. cellulose
Humans can digest starch but not cellulose because:
Answer C: explanation for every choice
A
Both starch and cellulose are polymers of glucose.
B
This is reversed. Starch has α(1→4) linkages, plus α(1→6) branches in amylopectin.
C
Correct. Cellulose is glucose joined by β(1→4) bonds. Humans make amylases for α linkages but no cellulase.
D
α(1→6) branches occur in amylopectin and glycogen. Cellulose is unbranched.
TakeawaySame monomer, different linkage: α(1→4) starch is digestible, β(1→4) cellulose is not.
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Reviewed 2026-11-05 by a medical student. Spot an error? Report it with question ID bb15.