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,adsorption,assimilation , egestion
(b) liver
(c) digestive
(d) villi
(e) 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 chewit for some time.(T/F)
Ans:
(a) F
(b) T
(c) T
(d) 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
Ans:
(a) (iii)small instestine
(b) (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 |
Ans:
| 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?
Ans:
The inner walls of small intestine has thousands of finger-like outgrowths called villi that helps in the process of adsorption.
They are located in the inner walls of small intestine.
Their main function is to increase the surface area for absorption of the digested food.
6. Where is the bile produced? Which component of the food does it digest?
Ans:
The bile juice is produced inside the liver.
The bile plays an important role in the digestion of fats.
7. Name the type of carbohydrates that can be digested by ruminants but not by humans. Give the reason also.
Ans:
The carbohydrate is called cellulose that is digested by ruminants but not by humans.
Ruminants have a large sac-like structure between the small intestine and large intestine. The cellulose of the food is digested here by the action of certain bacteria which are not present in humans.
8. Why do we get instant energy from glucose?
Ans:
The carbohydrates are broken down into simple sugars called glucose.Glucose breaks down easily with the help of oxygen into carbon dioxide and water, and energy is released.Glucose is not required to be digested and so the energy released is instant.
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 ________________.
Ans:
(i) Small intestine.
(ii) buccal cavity
(iii) stomach
(iv) small intestine
(v) large intestine