NCERT Solutions Class 7 Science Chapter 2 Nutrition in Animals

NCERT Solutions for Class 7 Science for chapter 2 Nutrition in Animals

Q.1 Fill in the blanks:

(a) The main steps of nutrition in humans are_____________,________ ,________,_______and_____

(b) The largest gland in the human body is______.

(c) The stomach releases hydrochloric acid and_____juices which act on food.

(d) The inner wall of the small intestine has many finger-like outgrowths called ______.

(e) Amoeba digests its food in the______.

Ans. 1

(a) Ingestion, digestion, absorption, assimilation and egestion

(b) Liver

(c) digestive

(d) Villi

(e) Food vacuole

Q.2 Mark ‘T’ if the statement is true and ‘F’ if it is false:

(a) Digestion of starch starts in the stomach. (T/F)

(b) The tongue helps in mixing food with saliva. (T/F)

(c) The gall bladder temporarily stores bile. (T/F)

(d) The ruminants bring back swallowed grass into their mouth and chew it for some time. (T/F)

Ans. 2

(a) False (b) True (c) True (d) True

Q.3 Tick (√_) mark the correct answer in each of the following:

(a) Fat is completely digested in the

(i) stomach (ii) mouth (iii) small intestine (iv) large intestine

(b) Water from the undigested food is absorbed mainly in the

(i) stomach

(ii) food pipe

(iii) small intestine

(iv) large intestine

Ans. 3

(a) Fat is completely digested in the: (iii) small intestine

(b) Water from the undigested food is absorbed mainly in the: (iv) large intestine

Q.4 Match the items of Column I with those given in Column II:

Ans. 4

Q.5 What are villi? What is their location and function?

Ans. 5 Thousands of minute finger-like projections or outgrowths found in the inner wall of small intestine are called villi. These increase the surface area for maximum and quick absorption of digested food from small intestine into the blood stream.

Q.6 Where is the bile produced? Which component of the food does it help to digest?

Ans. 6 Bile is produced in the liver. It acts upon the fat component of food and breaks down large-sized fat droplets into smaller ones.

Q.7 Name the type of carbohydrate that can be digested by ruminants but not by humans. Give the reason also.

Ans. 7 Cellulose is the type of carbohydrate that can be digested by ruminants and not by humans. It is so because a large sac-like structure called rumen is found in the ruminants between food pipe and small intestine; that contains numerous bacteria which can digest cellulose. Human alimentary canal does not contain such cellulose digesting bacteria and thus, cannot digest cellulose.

Q.8 Why do we get instant energy from glucose?
Ans. We get instant energy from glucose because it is the simplest sugar that readily breaks down into water and carbon dioxide with release of energy in a living cell. All the food components ultimately get converted into glucose.

Q.9 Which part of the digestive canal is involved in:

(i) absorption of food ____________.
(ii) chewing of food ______________.
(iii) killing of bacteria _____________.
(iv) complete digestion of food__________
(v) formation of faeces ___________.

Ans. 9

(i) Small intestine
(ii) Buccal cavity
(iii) Stomach
(iv) Small intestine
(v) Large intestine

Q.10. Write one similarity and one difference between the nutrition in Amoeba and human beings.

Ans. 10

a. Nutrition in Amoeba is similar to that of human beings because both comprise of five basic steps, which are ingestion, digestion, absorption, assimilation and egestio
b. One of the important differences in the nutrition in Amoeba with that of human beings is the lack of alimentary canal and digestive organs. Amoeba being a single-celled organism contains organelles for performing different set of functions instead of organs and organ systems.

Q.11. Match the items of Column I with suitable items in Column II:

Ans. 11

Q.12. Label Fig. 2.11 of the digestive system.

Ans. The well labeled diagram of the given figure is as follows:

Q.13. Can we survive only on raw, leafy vegetables/grass? Discuss.

Ans. 13 No, we cannot survive only on raw, leafy vegetables and grass. It is so because main component present in such a diet is cellulose which cannot be digested by human beings. Cellulose can only be digested by certain bacteria which are present in the rumen of ruminant animals. These bacteria breakdown the cellulose and produce nutrients and energy for themselves and the ruminants. Therefore, only ruminants can survive on diet consisting of raw vegetables and grass.