Why is cellulose in our diet not nourishing?
Answer: We lack the enzyme to hydrolyse β-glycosidic linkages, so cellulose passes undigested.
Solution
Cellulose is a polymer of β-D-glucose joined by β-1,4-glycosidic links; human digestive enzymes can cleave only α-linkages (starch). Unhydrolysed, cellulose yields no glucose — it is roughage, not nourishment.
CBSE Class 12 Board · 2003 · All India · Subjective