Because there are bacteria living in our guts which produce the enzyme (called cellulase) necessary to break cellulose into smaller parts. Otherwise it would be indigestable, and come out the way it came in.
cellulose
Humans can't digest cellulose.
Cellulose is a polysaccharide that cannot be digested by humans due to the lack of necessary enzyme, cellulase, in our digestive system. It passes through the gastrointestinal tract intact and provides bulk to aid in digestion and promote overall gut health.
Mostly it is the cellulose. It cannot be digested
starch is soluble in water, on the other hand cellulose is insoluble. also, the glucose molecules in starch and cellulose are linked differently, making it impossible to be broken down by humans.
Cellulose is a complex carbohydrate found in plant cell walls that cannot be digested by any mammal (including humans). This is because mammals lack the enzyme which breaks the β(1,4) linkages found within cellulose.
Glycogen can be digested by humans. Chitin and Cellulose, also knows as fiber, can not be digested by humans.
Cellulose
cellulose which is present in grass can be digested by ruminants but cannot be digested by humans
Cellulose cannot be hydrolyzed by the digestive system of most animals because they lack the necessary enzyme, cellulase, to break down its β-glucosidic bonds. While starch and glycogen can be digested by animals due to their α-glucosidic bonds, sucrose can be hydrolyzed by the enzyme sucrase. Therefore, cellulose is the molecule that most animals cannot digest.
cellulose
True. Cellulose, a type of fiber found in plant cell walls, cannot be digested by humans because we lack the necessary enzymes to break it down.