Chapter 3

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1. Fill in the blanks:

(a) The main steps of nutrition in humans are __________, __________,

__________, _________ and __________.

Ans: 

  •  Ingestion
  •  Digestion
  •  Absorption
  •  Assimilation
  •  Egestion


(b) The largest gland in the human body is __________.

Ans: liver.


(c) The stomach releases hydrochloric acid and ___________ juices which

act on food.

Ans: digestive.


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

called _________.

Ans: villi.


(e) Amoeba digests its food in the ____________ .

Ans: 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 () 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 I                                                           Column II

                     Food components                                                Product(s) of digestion

                     Carbohydrates                                                      Fatty acids and glycerol

                      Proteins                                                                Sugar

                      Fats                                                                        Amino acids


Ans: 

Column IColumn II
CarbohydratesSimple sugars
ProteinsAmino acids
FatsFatty acids and glycerol


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

Ans: Villi are finger-like projections which are richly supplied with blood vessels. They are present in the inner lining of the small intestine and help in the absorption of nutrients by increasing the surface area for absorption.


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

Ans: Bile is a fluid that is made and released by the liver and stored in the gallbladder. Bile helps with digestion. It breaks down fats into fatty acids, which can be taken into the body by the digestive tract.


7. Name the type of carbohydrate that can be digested by ruminants but

    not by humans. Give the reason also.

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


8. Why do we get instant energy from glucose?

Ans: Glucose is a simplest form of sugar which is easily absorbed by the blood whereas other carbohydrates are first broken down into glucose and then absorbed. Hence, glucose gives instant energy.


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: (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: Similarity between the nutrition in amoeba and human beings is that both are heterotrophs, they derive their nutritions from other organisms. Dissimilarity between them is that human beings have complex digestive system where food gets digested in separate regions while in amoeba food is digested in a food vacuole.



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 wate

                                                                                    (vii) Release of faeces

Ans: 

Column IColumn II
(a) Salivary gland(iii) Saliva secretion
(b) Stomach(iv) Acid release
(c) Liver(i) Bile juice secretion
(d) Rectum(vii) Release of faeces
(e) Small intestine(v) Digestion is completed
(f) Large intestine(vi) Absorption of water



Type by Jyotishna Hazarika

Colour By: Himashree Bora.