Science Class 7 Chapter 2 Nutrition in Animals NCERT Exercise Solution (Question-Answer)

Q1. Fill in the blanks:-

(a) The main steps of nutrition in human are __________ , _________ ,____________ ,___________ and ___________.

Answer– Ingestion, digestion, absorption, assimilation, egestion

(b) The largest gland in the human body is ___________.

Answer-Liver

(c) The stomach releases hydrochloric acid and ___________juices which act on the food.

Answer– Digestion

(d) The inner wall of the small intestine has many fingers like outgrowths called ______________.

Answer– Villi

(e) Amoeba digest its food in the _______________.

Answer-Food vacuole

Q2. Mark “T” if the statement is true and “F”  if it is false:-

(a) Digestion of starch starts in the stomach  ( T/F)

Answer– False

(b) The tongue helps in  mixing food with saliva  (T/F)

Answer– True

(c) The gall bladder temporarily stores bile (T/F)

Answer– True

(d) The ruminants bring back swallowed grass into their mouth and chew it for some time. (T/F)

Answer– True

Q3. 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

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

Q4. Match the items of column 1 with those given in column 2:

Answer-

Q5. What are Villi? What are their location and function?

Answer- The inner wall of the small intestine has thousands of finger-like outgrowths. These are called Villi (singular Villus). They are present in the small intestine of our digestive system. It provides with blood vessels. The Villi increase the surface area for absorption of digested food.

Q6. Where the bile produce ? Which component of the food does it help to digest?

Answer- Bile juice is produced in the liver. The bole juice stored in a sac called the gall bladder.

It helps In the digestion of fats. It breakdown large fat globule into smaller ones ( emulsification ) and thus helps in enzymatic action of fats.

Without bile, juice fat cannot be digested.

Q7. Name the type of carbohydrates that can be digested by ruminants but not by humans . Give the reason also.

Answer- Cellulose is the carbohydrates that can be digested by ruminants but not by humans.

Ruminants have a large sac-like structure between the small intestine and large intestine, where the food containing Cellulose digested by the action of certain bacteria. These bacteria are not present in humans.

Q8. Why do we get instant energy from glucose?

Answer- We get instant energy from glucose because glucose is a simple sugar. It an easily absorbed by the blood.

It easily breaks down in the cell with the help of oxygen which provides instant energy to the organism.

Whereas other Carbohydrates are first broken down into glucose and then absorbed.

Q9. Which part of the digestive canal is involved in–

(i) Absorption of food ____________________.

Answer- Small intestine

(ii) Chewing of food ______________________.

Answer- Mouth

(iii) Killing of bacteria ____________________.

Answer- Stomach

(iv) Complete digestion of food ____________________.

Answer- Small intestine

(v) Formation of faeces __________________.

Answer- Large intestine

Q10. Write one similarity and one difference between the nutrition in amoeba and human beings.

Answer- Similarity– Both human and amoeba has the holozoic type of nutrition. It means in both the digestive juices convert complex food into simpler soluble and absorbable substances.

Differences- Amoeba ingested food through Pseudopodia and engulf it but human beings take food by the mouth.

Q11. Match the items of column 1 with suitable items in column 2

Answer-

Q12. Label fig. 2.11 of the digestive system.

Answer- Below is the detailed labelled diagram of the human digestive system, but we have to memorise only main parts like- Salivary gland, Esophagus, Liver, Gall bladder, Bile duct, Stomach, Pancreas, Pancreatic duct, Appendix, Small intestine, Large intestine, Rectum and Anus.

Fig.This is full diagram of human digestive system.

Q13. Can we survive only on raw, leafy vegetables, grass? Discuss.

 Answer- No, we can not survive only on raw, leafy vegetables/grass because they are mainly rich in cellulose which is a type of carbohydrates. It can not be digested by us due to the lack of cellulose digestion enzyme in our body.