Question

Mammals lack the enzyme that hydrolyzes cellulose. Yet many mammals are herbivores and they eat grass and other plant material for nutrition. How can this be, given that they cannot digest the food they are eating?

Answer 1

Although herbivorous mammals cannot produce the enzyme needed to digest cellulose, the microorganisms in their digestive systems can, allowing them to break down plant material into usable energy.

Step-by-step explanation:

Herbivorous mammals can digest cellulose despite lacking the necessary enzymes themselves because they have evolved to harbor symbiotic microorganisms in their digestive systems.

These microorganisms produce the enzyme cellulase, which breaks down cellulose into glucose monomers that the animals can use as an energy source. Ruminants, such as cows, sheep, and goats, have specialized stomach chambers like the rumen where these microorganisms thrive. In addition, the appendix of some grazing animals also serves as a site for cellulose digestion.