Nutrition in Animals NCERT CBSE Class 7 Chapter 2 Exercise solution

NCERT CBSE Class 7 Chapter 2 Exercise Solution
Nutrition in Animals 
NCERT Class VII Chapter-2


1. Fill in the blanks:
(a) The main steps of nutrition in humans are __________, __________,__________, _________ and __________.
Answer- Ingestion, digestion, absorption, assimilation, egestion. 
(b) The largest gland in the human body is __________.
Answer- liver. 
(c) The stomach releases hydrochloric acid and ___________ juices which act on food.
Answer- gastric
(d) The inner wall of the small intestine has many finger-like outgrowths called _________.
Answer- Villi. 
(e) Amoeba digests its food in the ____________ .
Answer- Food vacuole. 

2. Mark ‘T’ if the statement is true and ‘F’ if it is false:
(a) Digestion of starch starts in the stomach. (T/F)
Answer- F
Correct statement- Digestion of starch starts in the mouth. 
(b) The tongue helps in mixing food with saliva. (T/F)
Answer- T
(c) The gall bladder temporarily stores bile. (T/F)
Answer- T
(d) The ruminants bring back swallowed grass into their mouth  and chew it for some time. (T/F)
Answer- T

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
Answer- (iii) small intestine
(b) Water from the undigested food is absorbed mainly in the
(i) stomach                (ii) foodpipe 
(iii) small intestine (iv) large intestine
Answer- (iv)Large intestine

4. Match the items of Column I with those given in Column II:
          Column I                         Column II
Food components             Product(s) of digestion
Carbohydrates                 Fatty acids and glycerol
Proteins                             Sugar
Fats                                    Amino acids
Answer- Carbohydrates ------------> sugar
               Proteins----------------> Amino acids
              Fats ---------------> Fatty acids and glycerol 

5. What are villi? What is their location and function?
Answer- Villi -
              -Thousands of finger like outgrowth
             - Present in small intestine. 
  Location of Villi- Inner surface of small intestine
  Function of Villi- Increase surface area of small 
                                  intestine. 
                                - Increase absorption of food. 

6. Where is the bile produced? Which component of the food does it help to digest?
Answer- Bile juice is produced in liver. 
              - Bile digest fats. 

7. Name the type of carbohydrate that can be digested by ruminants but not by humans. Give the reason also.
Answer- Cellulose. 
      Reason- Ruminants have rumen. 
                   - Bacteria are present in rumen. 
                  - Bacteria digest cellulose. 
        But human donot have rumen. Hence they  
        can't digest cellulose. 

8. Why do we get instant energy from glucose?
Answer-Because glucose is a simpler component. 
              Glucose ----------------------------------> Energy

9. Which part of the digestive canal is involved in:
(i) absorption of food ________________.
Answer- Small intestine
(ii) chewing of food ________________.
Answer- Buccal cavity or mouth
(iii) killing of bacteria ________________.
Answer- Stomach
(iv) complete digestion of food ________________.
Answer- Small intestine
(v) formation of faeces ________________.
Answer- Large intestine

10. Write one similarity and one difference between the nutrition in amoeba and human beings.
Answer- Similarity between nutrition in amoeba and human being:
        Ingestion, digestion, absorption, assimilation and absorption take place in both amoeba and human being. 

Difference between nutrition in amoeba and human being:
In amoeba- All steps are done by single cell. 
In human- Different organ perform different function. 

11. Match the items of Column I with suitable items in Column II 
           Column I                   Column II
  (a) Salivary gland       (i) Bile juice secretion
  (b) Stomach         (ii) Storage of undigested food
  (c) Liver                      (iii) Saliva secretion
  (d) Rectum                  (iv) Acid release
  (e) Small intestine     (v) Digestion is completed
  (f ) Large intestine    (vi) Absorption of water
                                       (vii) Release of faeces
Answer- 
(a) salivary gland ---> (iii) saliva  secretion
(b) stomach -------> (iv) acid release
(c) Liver -------> (i) bile juice secretion 
(d) Rectum -------> (ii) storage of undigested food. 
(e) small intestine ------>(v) digestion is complete
(f) Large intestine -------> (vi) absorption of water


13. Can we survive only on raw, leafy vegetables/grass? Discuss
Answer- We cannot survive only on leafy vegetables/grass.
 Because 
- Our body needs balanced diet. 
- Leafy vegetables/grass donot have all components of food. 
- Cellulose present in leafy vegetables/grass can't be digested by human. 

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