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1. Fill in the blanks:
(a) The main steps of nutrition in humans are ingestion, digestion, absorption, assimilation, egestion.
(b) The largest gland in the human body is liver.
(c) The stomach releases hydrochloric acid and digestive juices, which act on food.
(d) The inner wall of the small intestine has many finger-like outgrowths called villi.
(e) Amoeba digests its food in the 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)
Ans: False
(b) The tongue helps in mixing food with saliva. (T/F)
Ans: True
(c) The gall bladder temporarily stores bile. (T/F)
Ans: True
(d) The ruminants bring back swallowed grass into their mouth and chew it for some time. (T/F)
Ans: True
3. Tick (ü) 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
Ans: (iii) Small intestine
(b) Water from the undigested food is absorbed mainly in the
(i) stomach (ii) foodpipe (iii) small intestine (iv) large intestine
Ans: (iv) Large intestine
4. Match the items of Column I with those given in Column II:
|
Column 1 |
Column 2 |
|
Food components |
Products of digestion |
|
Carbohydrates |
Fatty acids and glycerol |
|
Proteins |
Sugar |
|
Fats |
Amino acids |
Ans:
|
Column 1 |
Column 2 |
|
Food components |
Products of digestion |
|
Carbohydrates |
Sugar |
|
Proteins |
Amino acids |
|
Fats |
Fatty acids and glycerol |
5. What are villi? What is their location and function?
Ans: Villi are the finger-like outgrown structure present on the wall of small intestine. Their main function is to absorb the fatty acid and sugar and transport it to the blood vessels.
6. Where is the bile produced? Which component of the food does it help to digest?
Ans: The bile is produced by the liver, which helps in the digestion of fats.
7. Name the type of carbohydrate that can be digested by ruminants but not by humans. Give the reason also.
Ans: Cellulose is the type of carbohydrate that can be digested by ruminants but not by humans because ruminants have bacteria that helps to digest the cellulose but that bacteria is not found in humans.
8. Why do we get instant energy from glucose?
Ans: Glucose is the primary source of energy in organisms. It is a simple sugar, which is easily broken down, and hence it provides instant energy.
9. Which part of the digestive canal is involved in:
(i) absorption of food small intestine.
(ii) chewing of food mouth
(iii) killing of bacteria stomach.
(iv) complete digestion of food small intestine.
(v) formation of faeces large intestine.
10. Write one similarity and one difference between the nutrition in amoeba and human beings.
Ans: Similarities: In amoeba and human beings the digestive juices helps in breaking down of food into simpler substance that release energy.
Difference: The process of digestion is simple in amoeba, while it is very complex in human beings.
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 |
Ans:
|
Column I |
Column II |
|
(a) Salivary gland |
(i) Saliva secretion |
|
(b) Stomach |
(ii) Acid release |
|
(c) Liver |
(iii) Bile juice secretion |
|
(d) Rectum |
(iv) Storage of undigested food |
|
(e) Small intestine |
v) Digestion is completed |
|
(f ) Large intestine |
(vi) Absorption of water |
12. Label Fig. 2.11 of the digestive system.
Ans:
13. Can we survive only on raw, leafy vegetables/grass? Discuss.
Ans: No, we cannot survive on only raw, leafy vegetable and grass.