NCERT Solution class 7 Science Chapter 2

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NCERT Solution class 7  Science Chapter 2

 

Chapter – 02   Nutrition in Animals

Chapter Exercise

Page no. – (20)

 

Q.1- Fill in the blanks:-

  1. The main steps of nutrition in humans are ____, ____, ____, ____ and ____.
  2. The largest glands in the human body is ____.
  3. The stomach releases hydrochloric acid and ____ juices which act on food.
  4. The inner wall of the small intestine has many finger – like outgrowths called ____.
  5. Amoeba digests its food in the ____.

Ans.1-

  1. The main steps of nutrition in humans are __ingestion__, __digestion__, __absorption__, __assimilation__ and __egestion
  2. The largest glands in the human body is __liver
  3. The stomach releases hydrochloric acid and __gastric__ juices which act on food.
  4. The inner wall of the small intestine has many finger – like outgrowths called __villi
  5. Amoeba digests its food in the __food vacuole

 

Q.2- Mark “T” if the statement is true and “F” if it is false:-

  1. Digestion of starch starts in the stomach. (T/F)
  2. The tongue helps in mixing food with saliva. (T/F)
  3. The gall bladder temporarily stores bile. (T/F)
  4. The ruminants bring back swallowed grass into their mouth and chew it for some times. (T/F)

Ans.2-

  1. F
  2. T
  3. T
  4. T

 

Q.3- Tick Mark the Correct answer in each of the following:

  1. fat is completely digested in the
  2. Stomach
  3. Mouth
  • Small Intestine
  1. Large Intestine
  2. Water from the undigested food is absorbed mainly in the
  3. Stomach
  4. Food pipe
  • Small Intestine
  1. Large Intestine

Ans.3-

  1. Small Intestine
  2. Large Intestine.

 

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

Column I                                        Column II

Food Component                         Product(s) of Digestion

Carbohydrates                              Fatty acids and glycerol

Protein                                           Sugar

Fats                                                 Amino acids

Ans.4-

Column I                                        Column II

Food Component                         Product(s) of Digestion

Carbohydrates                              Sugar

Protein                                           Amino acids

Fats                                                 Fatty acids and glycerol

 

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

Ans.5- The finger-like projections or outgrowth are known as villi. They are present in the small intestine of our digestive system.

 

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

Ans.6- Bile juice is produced in the liver. It helps in the digestion of fats by breaking large fat globule into the smaller globules.

 

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

Ans7- Cellulose is the carbohydrate that can be digested by ruminants. Ruminants have large sac like structure between the small intestine and large intestine. The cellulose of the food is digested by the action of certain bacteria which are not present in humans.

 

Q.8- Why do we get instant energy from glucose?

Ans.8- Because it easily breaks down in the cell with the help of oxygen which provides instant energy to the organism. Glucose does not need digestion, it is directly absorbed into the blood.

 

Q.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 faces ____.

Ans.9-

  1. Absorption of food __Small Intestine__,
  2. Chewing of food __Mouth__,
  3. Killing of bacteria __Stomach__,
  4. Complete digestion of food __Small Intestine__,
  5. Formation of faces __Large Intestine

 

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

Ans.10-

Similarity Difference
Amoeba and human being both are follow the holozoic type of nutrition. Human intake food through buccal cavity. In amoeba food is ingested through pseudopodia.

 

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

Column I                                        Column II

  1. Salivary gland                         Bile juice secretion
  2. Stomata                                  Storage of undigested food
  3. Liver                                        Saliva Secretion
  4. Rectum                                   Acid Release
  5. Small intestine                       Digestion is Completed
  6. Large intestine                       Absorption of Water

                                               vii.    Release of faeces

Ans.11-

Column I                                        Column II

  1. Salivary gland                       Saliva Secretion
  2. Stomata     Acid Release
  3. Liver                                     Bile juice secretion
  4. Rectum    Storage of undigested food
  5. Small intestine     Digestion is Completed
  6. Large intestine     Absorption of Water

 

Page no.- (22)

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

Ans.12-    

Digestive System - 2nd Period Group 7 Tennis

Fig. 2.11  A part of human digestive system

Q.13- Can we survive only on row, leafy vegetable/ grass? Discuss.

Ans.13- No, we cannot survive only on raw, leafy vegetables because they mainly consist of Cellulose which cannot be digested by us due to lack of cellulose digesting enzyme in our body.