ncert solutions for class 7 science chapter 2
ncert solutions for class 7 science chapter 2 (Nutrition in Animals) In this chapter The student learn about the digestive system .We also learn buccal cavity , stomach, oesophagus, small intestine, large intestine, rectum,Absorption, Egestion, Assimilation, Amino acid, Cellulose, canine, Fatty acid, Villi, Rumen, Pancreas etc.Digestion in Grass eating animals and Digestion in Amoeba.
Question 1: Fill in the blanks:
(a) The main steps of the nutrition in human are Ingestion, Digestion, Absorption, Assimilation and Egestion.
(b) The largest gland in the human body is Liver.
(c) The stomach releases Hydrocloric 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.
Question 2: Mark ‘T’ if the statement is true and ‘F’ if it is false:
(a) Digestion of starch starts in the stomach. [ F]
(b) The tongue helps in mixing food with saliva. [T]
(c) The gall bladder temporarily stores in bile. [T]
(d) The ruminants bring back swallowed grass into their mouth and chew it for some time. [T]
Question 5: What are Villi? What is their location and function?
Answer 5: The inner wall of the small intestine have thousands of finger like outgrowths, these are called Villi. Villi increase the surface area for absorption of the digested food. Each Villus has a network of thin and small blood vessels close to its surface. The surface of the villi absorbs the digested food materials.
Question 6: Where is the bile produced? Which component of the food does it help to digest?
Answer 6: Bile produced in the liver .It help to digest the fat of the food.
Question 7: Name the type of carbohydrate that can be digested by ruminants but not by humans. Give the the reason also.
Answer 7: Cellulose is a carbohydrate that can be digested by the ruminants but not by the humans. Because 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 certain bacteria but in humans such organs/bacteria are not present.
Question 8: Why do we get instant energy from glucose?
Answer 8: We get instant energy from glucose because glucose easily break down with the help of oxygen into carbon dioxide and water and it release energy.
Question 9: Which part of the digestive canal is involved in:
(i) absorption of food Small intestine
(ii) chewing of food Buccal cavity
(iii) killing of bacteria Stomach
(iv) complete digestion of food Small intestine
(v) formation of faeces Large intestine
Question 10 : Write one similarity and one difference between the nutrition in amoeba and human being.
Answer 10 : Similarity– Basic digestion process in amoeba and human being are similar. In amoeba, it secret the digestive juice and break down the food into simple substances in food vacuole and absorbed the digested food. Similarly in human being secret the digestive juice into the food and break down it into simple substances then digest and absorbed.
Difference – Digestive system in amoeba is simple but in human being, it is complex. Amoeba capture it’s food by pseudopodia and take inside the food vacuole after digestion expell out it. But in human being food taken by mouth and digested by stomach after digestion it absorbed by intestine and expell out the waste material in form of faeces.
