Digestion of cellulose ....

[srimukh]

All herbivorus animals have enzyme called 'Cellulase', which digests the cellulose present in plants they eat.

 

But we lack that enzyme, but even then we can digest the RAW FRUITS & VEGETABLES we eat. How is that possible?

Does the remaining nutrients get digested and the left over cellulose is thrown out intact?

[Mokele]

Technically, no animals have cellulase - it's produced by bacteria that live in the gut.

 

Thing is, it takes a long time to digest cellulose, even if you have loads of the necessary bacteria, which is why most pure herbivores, such as cows, have tremendously long and convoluted digestive systems, with very long gut passage times (time from ingestion to excretion). We have the gut of an omnivore, so we can't keep food inside us long enough to actually digest a significant fraction of the cellulose.

 

Also, you're right in that we digest the other nutrients - plants have a lot more in them than just cellulose, and we can get at that fairly easily.

[GDG]

But we lack that enzyme, but even then we can digest the RAW FRUITS & VEGETABLES we eat. How is that possible?

Does the remaining nutrients get digested and the left over cellulose is thrown out intact?

 

Yep: it's called roughage.