NCERT Solutions Class 7 Science
The NCERT Solutions in English Language for Class 7 Science Chapter – 2 (Nutrition in Animals) has been provided here to help the students in solving the questions from this exercise.
Chapter – 2 (Nutrition in Animals)
1. Fill in the blanks:
(a) The main steps of nutrition 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 ____________ .
Answer –
(a) The main steps of nutrition in humans are ingestion, digestion, absorption, assimilation and egestion.
(b) The largest gland in the human body is Liver.
(c) The stomach releases hydrochloric 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.
2. Mark ‘T’ if the statement is true and ‘F’ if it is false:
(a) Digestion of starch starts in the stomach. (T/F)
(b) The tongue helps in mixing food with saliva. (T/F)
(c) The gall bladder temporarily stores bile. (T/F)
(d) The ruminants bring back swallowed grass into their mouth and chew it for some time. (T/F)
Answer –
(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 bile. (T)
(d) The ruminants bring back swallowed grass into their mouth and chew it for some time. (T)
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
(b) Water from the undigested food is absorbed mainly in the
(i) stomach (ii) foodpipe (iii) small intestine (iv) large intestine
Answer –
(a) Fat is completely digested in the – (iii) small intestine
(b) Water from the undigested food is absorbed mainly in the – (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 |
Solution:
| Column – I | Column – II |
| Food components | Product(s) of digestion |
| Carbohydrates | Sugar |
| Proteins | Amino acids |
| Fats | Fatty acids and glycerol |
5. What are villi? What is their location and function?
Answer – Villi are the finger-like projections in the inner walls of the small intestine. The Villi increase the surface area for absorption of digested food.
6. Where is the bile produced? Which component of the food does it help to digest?
Answer – Bile juice is produced by the liver and stored in gall bladder. It helps in digestion fats present in food.
7. Name the type of carbohydrate that can be digested by ruminants but not by humans. Give the reason also.
Answer – Cellulose is the carbohydrate that can be digested by ruminants but not by humans because ruminants have a large sac-like structure called rumen which is located between the small intestine and large intestine. Certain bacteria are present in rumen which helps in digesting cellulose.
8. Why do we get instant energy from glucose?
Answer – Glucose is a simple 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 ________________.
Answer –
(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.
10. Write one similarity and one difference between nutrition in amoeba and human beings.
Answer –
| Digestion in humans | Digestion in Amoeba |
| Similarity – Both amoeba and human beings follow the holozoic type of nutrition. | |
| Difference – Humans intake food through buccal cavity. | Difference – In amoeba food is ingested through pseudopodia. |
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 water |
| (vii) Release of faeces |
Answer –
| Column – I | Column – II |
| (a) Salivary gland | (iii) Saliva secretion |
| (b) Stomach | (iv) Acid release |
| (c) Liver | (i) Bile juice secretion |
| (d) Rectum | (ii) Storage of undigested food |
| (e) Small intestine | (v) Digestion is completed |
| (f) Large intestine | (vi) Absorption of water |
12. Label Fig. 2.11 of the digestive system.
Answer –
13. Can we survive only on raw, leafy vegetables/grass? Discuss.
Answer – No, we cannot survive only on raw, leafy vegetables/grass, because we cannot get all required nutrients, such as carbohydrates, proteins, lipids, vitamins and minerals, from them. Moreover raw vegetables may not be digested easily as compared to cooked vegetables.
