Question

Humans cannot digest cellulose like cattle do because
A) They have smaller stomach
B) They do not have cellulose-digesting bacteria in their stomach
C) They do not consume cellulose
D) They have less digesting capacity than ruminants

Answer 1

Hint:Stomachs have many different enzymes that involve in the break-down different components of food like carbohydrates, proteins, and fats. All the enzymes, hydrochloric acid, and digestive juice work together but some components like fibres do not get digested.

Complete answer
To answer this question, we have to know about the carbohydrates. Carbohydrates are found in many forms in our food like glucose, fructose, and sucrose. These are simple carbohydrates that are found in fruits, candies, and soda pop but there are also some complex sugars such as starch that consist of long chains of sugar. In the digestive tract the complex sugar is break-down into simple sugar before digestion. The simple sugar that is formed is absorbed by the small intestine and released to the bloodstream. Some of the carbohydrates come in fiber forms that are not digestible but important for our dietary.
Now, cellulose is a carbohydrate that is found in plants. Cellulose is sometimes found as dietary fibers and the fibers cannot be digested by humans but the consumption of fibers is important as it allows the food to move through the digestive tract and also help to eliminate the wastes. The main reason behind this fact is that the human guts do not have the bacteria that help in the digestion of the cellulose while the cattles have such bacteria.

Hence, the correct answer is ‘B’. They do not have cellulose-digesting bacteria in their stomach.

Note:Even the enzyme that requires for the digestion of cellulose is not present in the human guts. But the cellulose provides smoothening of the intestine so that the food moves easily. Especially in the case of colon cancer patients were asked to consume fibre rich food more.