NCERT 7th Class (CBSE) Science: Nutrition in Animals

Question: What is the function of taste buds?

Answer: The function of taste bud is that it can detect all tastes – sweet, salty, sour and bitter.

Question: What is saliva and where is it produced?

Answer: Saliva is a digestive juice which is secreted by three pairs of salivary glands in our mouth.

Question: How long does food stay in the stomach.

Answer: Food stays in the stomach from a few minutes to few hours depending on the type of food eaten. 

Question: What are villi? What is their location and function?

Answer: Villi are the finger like projections on the inner walls of small intestine. These villi increase the surface area of the inner wall for absorption of digested food.

Question: Where is the bile produced? Which component of the food does it help to digest?

Answer: The liver secretes bile juice that is stored in a sac called the gall bladder. The bile plays an important role in the digestion of fats.

Question: Name the type of carbohydrate that can be digested by ruminants but not by humans. Give the reason also.

Answer: The grass is rich in cellulose, a type of carbohydrate. Many animals, including humans, can not digest cellulose. The cellulose can be digested by ruminants but not by humans because they have a large sac – like structure between the small intestine and large intestine. The cellulose of the food is digested here by the action of certain bacteria which are not present in humans.

Question: Why do we get instant energy from glucose?

Answer: We get instant energy from glucose, because in the cells, glucose breaks down with the help of oxygen into carbon dioxide and water and energy is released.