Class 7 Science NCERT Solutions for Chapter – 2 Nutrition in Animals

Nutrition in Animals

Question 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 …………. .

Solution:
(a) ingestion,  digestion, absorption, assimilation and egestion.
(b) liver
(c) digestive
(d) villi
(e) food vacuole.

Question 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)

Solution:
(a) F
(b) T
(c) T
(d) T

Question 3.
Tick () mark the Correct answer in each of the following :
(a)
Fat is completely digested in the

  1.  stomach
  2.  mouth
  3.  small intestine
  4. large intestine

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

  1. stomach
  2.  foodpipe
  3.  small intestine
  4.  large intestine

Solution:
(a)-3 small intestine
(b)-4 large intestine

Question 4.
Match the items of Column I with those given in Column n :

Solution:

Column I Column II 
Food componentsProduct(s) of digestion
CarbohydratesFatty acids and glycerol
ProteinsSugar
FatsAmino acids
Column IColumn II
CarbohydratesSugar
ProteinsAmino acids
FatsFatty acids and glycerol

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

Solution:
The inner walls of the small intestine have thousands of finger-like outgrowths. These are called villi. Villi are located in the small intestine. The villi increase the surface area for absorption of the digested food. Each villus has a network of thin and small blood vessels close to its surface. The surface of the villi absorbs the digested food materials.

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

Solution:
Bile is produced by liver and is stored in gall bladder. Bile juice digests fat.

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

Solution:
Cellulose is a type of carbohydrate that can be digested by ruminants but not by humans. Ruminants have a large sac-like structure called rumen which is present in between the small intestine and large intestine. The cellulose is digested here by the action of certain bacteria which are not present in humans.

Question 8.
Why do we get instant energy from glucose?

Solution:
Glucose is the simplest form of carbohydrate which can be broken down easily to give energy. So, glucose is called instant energizer.

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

  1.  absorption of food  …………. .
  2. chewing of food …………. .
  3.  killing of bacteria …………. .
  4.  complete digestion of food …………. .
  5. formation of faeces …………. .

Solution:

  1.  small intestine
  2.  buccal cavity
  3.  stomach
  4.  small intestine
  5.  large intestine

Question 10.
Write one similarity and one difference between the nutrition in amoeba and human beings.

Solution:

  1. Similarity :
    Both amoeba and human use digestive juices to digest food.
  2. Difference :
    Human needs to chew food, whereas in amoeba, there is no chewing.

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

Column I Column II
(a) Salivary gland
(b) Stomach
(c) Liver
(d) Rectum
(e) Small intestine
(f) Large intestine
(i) Bile juice secretion
(ii) Storage of undigested food
(iii) Saliva secretion
(iv) Acid release
(v) Digestion is completed
(vi) Absorption of water

Solution:
(a)-(iii)
(b)-(iv)
(c)-(i)
(d)-(ii)-(vii)
(e)-(v)
(f)-(vi)

Question 12.
Label of the digestive system (as given in the NCERT Textbook Exercise)

Solution:

Do your self ……..

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

Solution:
No. Because to live a healthy life, we need a complete balance of all nutrients. Raw leafy vegetables/grass may have cellulose which can not be digested by us. So, we cannot survive only on raw, leafy vegetables/grafs.

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