Tag: nutrition and diet

There are 20 amino acids found inside our body. The name of these 20 common amino acids is as follows: alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine. They get combined in an unlimited number of configurations to construct all the required proteins with which our body is built.

Humans lack the enzyme necessary to digest cellulose. Hay and grasses are particularly abundant in cellulose, and both are indigestible by humans (although humans can digest starch). Animals such as termites and herbivores such as cows, koalas and horses all digest cellulose, but even these animals do not themselves have an enzyme that digests this material. Instead, these animals harbour microbes that can digest cellulose. Animals such as cows have anaerobic bacteria in their digestive tracts which digest cellulose. Cows are ruminants. Ruminants have several stomachs that break down plant materials with the help of enzymes and bacteria. The partially digested material is then regurgitated into the mouth, which is then chewed to break the material down even further. The bacterial digestion of cellulose by bacteria in the stomachs of ruminants is anaerobic, meaning that the process does not use oxygen. 

The digestive system of Humans has many enzymes, and acids to break down and digest all kinds of different foods (carbohydrates. proteins and fats), but do not have the enzymes needed to break down cellulose. Cows, Goats, Sheep and other animals that graze on many organic foods(For example, grass) do have the enzymes needed to break down cellulose. Hence The part of food that is not digested in the body is Cellulose because the cellulose-digesting enzyme is absent.

So, the correct answer is 'cellulose'.