NCERT Class 7 Science Chapter 2 - Nutrition in Animals

Chapter 2 - Nutrition in Animals

Question 1: Fill in the blanks:
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 vacuoles.

Question 2: Mark ‘T’ if the statement is true and ‘F’ if it is false:
a) Digestion of starch starts in the stomach. (False)
b) The tongue helps in mixing food with saliva. (True)
c) The gall bladder temporarily stores bile. (True)
d) The ruminants bring back swallowed grass into their mouth and chew it for some time. (True)

Question 3: Tick 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
Answer: 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
Answer: iv) Large intestine

Question 4: What are villi? What is their location and function?
Answer: Villi are the finger-like projections or outgrowth. They are present in the small intestine of our digestive system.

Question 5: Where is the bile produced? Which component of the food does it help to digest?
Answer: Bile juice is produced in the liver, and it helps in the digestion of fats by breaking large fat globule into smaller ones.

Question 6: 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 humans lack cellulose enzyme required to digest the cellulose.

Question 7: 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.

Question 8: 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

Question 9: Write one similarity and one difference between nutrition in amoeba and human beings.
Answer:
• Similarity: Both amoeba and human beings follow the holozoic type of nutrition.
• Difference: Humans intake food through buccal cavity. In amoeba food is ingested through pseudopodia.

Question 10: Can we survive only on raw, leafy vegetables/grass? Discuss.
Answer: 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.