Topic outline

    • Nutrition in Animals


      Question 84:  
      Boojho took some grains of boiled rice in test tube ‘A’ and Paheli took boiled and chewed rice in test tube ‘B’. Both of them poured 1 -2 drops of iodine solution into the test tube and observed the colour change. What colour change would they have observed? Give reasons for your answer.


      After pouring iodine solution in test tube ‘A’, its colour will change to blue-black due to the presence of starch in boiled rice. In test tube B, colour of iodine will not change because the saliva breaks down the starch into sugars.


      Question 85:  
      Explain the process of digestion in grass eating animals.
      Explain how the digestion of cellulose occurs in grass eating animals.


      Grass eating animals quickly swallow the grass and store it in a part of the stomach called rumen. Here the food gets partially digested and is called cud. But later the cud returns to the mouth in small lumps and the animal chews it.


      Question 86:  
      Why it is advised not to eat hurriedly and talk or laugh while eating?


      When we eat food epiglottis (flap-like valve) closes but when we talk while eating the epiglottis would remain open and the food may enter windpipe which may trigger violent coughing to clear the food material out of trachea or may get serious by chocking.


      Question 87:  
      What is the role of liver in digestion of fats?


      The liver is a reddish brown gland situated in the upper part of the abdomen on the right side. It is the largest gland in the body. It secretes bile juice that is stored in a sac called the gall bladder. The bile plays an important role in the digestion of fats.


      Question 88:  
      Write a short note on digestion in starfish.


      Starfish feeds on animals covered by hard shells of calcium carbonate.

      After opening the shell, the starfish pops out its stomach through its mouth to eat the soft animal inside the shell. The stomach then goes back into the body and the food is slowly digested.


      Question 89: 
      Write a short note on large intestine.


      The large intestine is wider and shorter than small intestine. It is about 1.5 metre in length. Its function is to absorb water and some salts from the undigested food material. The remaining waste passes into the rectum and remains there as semi-solid faeces. 


      Question 90:  
      Fill in the blanks with suitable words.
      (a) The alimentary canal stretches from_____to _____.
      (b) Teeth are rooted in separate _____ in between the_____.
      (c) Digestion of food starts in _____ and gets completed in_____.
      (d) _____ is the largest gland in the human body.


      (a) mouth, anus

      (b) sockets, gums

      (c) buccal cavity, small intestine

      (d) Liver


      Question 91:  
      Name the parts of the alimentary canal where
      (i) water gets absorbed from undigested food
      (ii) digested food gets absorbed
      (iii) taste of the food is perceived
      (iv) bile juice is produced.


      (i) Large intestine

      (ii) Small intestine

      (iii) Tongue

      (iv) Liver


      Question 92:  
      How can we prevent tooth decay?


      We can prevent tooth decay in the following manner:

      1. By cleaning the teeth with a brush or datun and dental floss at least twice day and rinse the mouth after every meal. 

      2. By not putting dirty fingers or any unwashed object in the mouth.


      Question 93:  
      What is the difference between the alimentary canal and the digestive system?


      The alimentary canal is a muscular hollow continuous tubular organ that starts at the mouth and ends at the anus and is responsible for the digestion and absorption of the ingested food and liquids. The alimentary canal (digestive tract) and the associated glands together constitute the digestive system.


      Question 94:  
      What are villi? What is their location and function?


      The inner walls of the small intestine have thousands of finger-like outgrowths. These are called villi (singular villus). These are found in small intestine. 


      1. The villi increase the surface area for absorption of the digested food. 

      2. The surface of the villi absorbs the digested food materials.


      Question 95:  
      Mark the following statements as true or false. If false, write the correct statements.
      (a) Tongue is attached to the roof of the mouth cavity at the back.
      (b) The large intestine is longer and wider than the small intestine of the human alimentary canal.
      (c) Mucus protects the stomach lining from damage.
      (d) All heterotrophs have a similar basic process of nutrition.


      (a) False — Tongue is attached to the floor of the mouth cavity at the back.

      (b) False – The large intestine is shorter and wider than the small intestine of the human alimentary canal.

      (c) True

      (d) True


      Question 96:  
      What are the functions of the tongue in human body?


      Functions of the tongue in human body

      1. It helps in talking. 
      2. It mixes saliva with the food during chewing and helps in swallowing food. 
      3. It has taste buds that detect different tastes of food. 


      Question 97:  
      How food moves in the opposite direction during vomiting?


      The swallowed food passes into the foodpipe or oesophagus. Food is pushed down by movement of the wall of the foodpipe. Actually this movement takes place throughout the alimentary canal and pushes the food downwards. At times the food is not accepted by our stomach and is vomited out.


      Question 98:  
      Draw the labelled diagram of tongue showing different region for taste buds.



      Question 99:  
      Draw a labeled diagram of amoeba.



      Question 100:  
      Name the type of carbohydrate that can be digested by ruminants but not by humans. Give the reason also.


      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 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.


      Question 101:  
      What is the difference between primary and permanent teeth?


      The first set of teeth grows during infancy and they fall off at the age between six to eight years. These are termed milk teeth. 

      The second set that replaces them are the permanent teeth. The permanent teeth may last throughout life or fall off during old age or due to some dental disease.


      Question 102:  
      What is tooth decay?
      What is the process of tooth decay?


      Bacteria are present in our mouth but they are not harmful to us. However, if we do not clean our teeth and mouth after eating, many harmful bacteria also begin to live and grow in it. These bacteria break down the sugars present from the leftover food and release acids. The acids gradually damage the teeth. This is called tooth decay.


      Question 103:  
      Explain the process of nutrition in Amoeba.


      Amoeba feeds on some microscopic organisms. When it senses food, it pushes out pseudopodia around the food particle and engulfs it. The food becomes trapped in a food vacuole. Digestive juices are secreted into the food vacuole. They act on the food and break it down into simpler substances. Gradually the digested food is absorbed.