2 NUTRITION IN ANIMALS

Transcription

1 2 NUTRITION IN ANIMALS Q.1. You have studied in class VI that food consists of many components. Try to recall and list them below : Ans. 1. Carbohydrates 2. Fats 3. Proteins 4. Minerals 5. Vitamins 6. Water Q.2. How food moves in the opposite direction during vomiting? Ans. Food is pushed down by movement of the walls of the foodpipe. This movement takes place throughout the alimentary canal and pushes the food downwards. But when our stomach is completely full or even after eating stale food, the food is not accepted by our stomach, therefore, it is pushed in the opposite direction and vomited out. Q.3. Why animals such as cow, buffalo etc. cannot chew food properly at the time they take it in? 11

2 Ans. Animals such as cow, buffalo etc. cannot chew food properly at the time they take it in because these animals eat grass which is rich in cellulose and cannot be digested easily. Q.4. Why we cannot digest cellulose like the cattle do? Ans. We cannot digest cellulose like the cattle do because we do not have the bacteria present in our body that can digest cellulose. TEXT BOOK EXERCISES AND ANSWERS PAGE NO Q.1. Fill in the blanks : (a) The main steps of digestion in humans are,,, and. (b) The largest gland in the human body is. (c) The stomach releases hydrochloric acid and juices which act on food. (d) The inner wall of the small intestine has many finger like outgrowths called. (e) Amoeba digests its food in the. Ans. (a) ingestion, digestion, absorption, assimilation, egestion, (b) liver, (c) digestive, (d) villi, (e) food vacuole. Q.2. Mark T if the statement is true and F it is false : 12

3 (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. Q.3. Tick ( ) mark the correct answer in each of the following : (a) Fat is completely digested in the (i) stomach (iii) small intestine (ii) mouth (iv) large intestine Ans. (iii) Small intestine. (b) Water from the undigested food is absorbed mainly in the (i) stomach (ii) food pipe (iii) small intestine (iv) large intestine 13

4 Ans. (iv) Large intestine. Q.4. Match the items of column I with those given in column II : Column I Food components Carbohydrates Proteins Fats Column II Product (s) of digestion Fatty acids and glycerol Sugar Amino acids Ans. Column I Food components Carbohydrates Proteins Fats Column II Product (s) of digestion Sugar Amino acids Fatty acids and glycerol Q.5. What are villi? What is their location and function? Ans. Villi are finger like projections located in the inner wall of small intestine. Function : Each villus has a network of thin and small blood vessels close to its surface. The surface of the villi absorbs the digested food 14

5 materials. The absorbed substances are transported via the blood vessels to different organs of the body. Q.6. Where is bile produced? Which component of the food does it digest? Ans. Bile is produced by the liver. It is stored in the gall bladder. The bile plays an important role in the digestion of fat. Q.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 but not by humans. The cellulose of the food is digested by the action of certain bacteria, which are not present in humans. So, human body cannot digest cellulose. Q.9. Why do we get instant energy from glucose? Ans. We get instant energy from glucose as glucose easily breakdown in the cell with the help of oxygen and give out Carbon dioxide, water and energy. Q.10. Which part of the digestive canal is involved in (i) absorption of food. 15

6 (ii) chewing of food. (iii) killing of bacteria. (iv) complete digestion of food. (v) formation of faeces. Ans. (i) Small intestine (ii) Mouth (iii) Stomach (iv) Small intestine (v) Large intestine. Q.11. Write one similarity and one difference between the nutrition in amoeba and human beings. Ans. (i) Similarity between the nutrition in amoeba and human beings. The process of digestion of food and release of energy is same in amoeba and human beings. (ii) Difference between the nutrition in amoeba and human beings. 16

7 All the process of digestion take place in the food vacuole. However, in human beings different organs perform the functiond of digestion. Q.12. Match the items of Column I with suitable items in Column II. Column I (a) Salivary gland (b) Stomach (c) Liver (d) Rectum (e) Small intestine (f) Large intestine Column II (i) Bile juice secretion (ii) Storage of undigested food (iii) Saliva secretion (iv) Acid release (v) Digestion is completed (vi) Absorption of water (vii) Release of faeces Ans. Column I (a) Salivary gland (b) Stomach (c) Liver (d) Rectum (e) Small intestine (f) Large intestine Column II Saliva secretion Acid release Bile juice secretion Storage of undigested food Digestion is completed Absorption of water 17

8 Q.13. Label the figure of the digestive system. Ans. Salivary gland, esophagus, liver, gallbladder, large intestine, appendix, anus, mouth, lungs, stomach, pancreas, small intestine, rectum. Q.14. Can we survive only on raw, leafy vegetables / grass? Discuss. Ans. Our body has different organs to digest the different components of the food. For example, the saliva present in the buccal cavity breaks down the starch into sugars, the digestive 18

9 juices present in the stomach help to break down the proteins, the bile secreted by the liver plays an important role in the digestion of fats, etc. Our body does not have the enzyme or digestive juice to digest raw, leafy vegetables / grass. Thus, we cannot survive only on raw, leafy vegetables / grass. EXTENDED LEARNING ACTIVITIES AND PROJECT Q.1. Visit a doctor and find out : (i) Under what conditions does a patient need to be on a drip of glucose? (ii) Till when does a patient need to be given glucose? (iii) How does glucose help the patient recover? Write the answers in your notebook. Ans. (i) When a patient is weak and unable to perform the various activities, he / she needs to be on drip of glucose. (ii) Till a patient is completely fit. (iii) Glucose is a form of carbohydrate. We get instant energy from glucose as glucose easily breakdown in the cell with the help of oxygen and give out carbon dioxide, water and energy. 19

10 Q.2. Find out what vitamins are and get the following information. (i) Why are vitamins necessary in the diet? (ii) Which fruits or vegetables should be eaten regularly to get vitamins? Ans. Vitamins are organic compounds which help to protect our body against diseases. (i) Vitamins are necessary in the diet because they keep us healthy and prevent diseases. Vitamins help to perform chemical reactions in the cell. (ii) Fruits Apples, banana, guava, grapes etc. Vegetables Carrot, green leafy vegetable, spinach etc. 20