(a) With the help of an activity, explain the action of saliva on the food we eat. (b) Why is bile juice…
(a) With the help of an activity, explain the action of saliva on the food we eat.
(b) Why is bile juice important in the process of digestion ?
Solution
(a) Take 1 ml 1% starch solution in two test tubes A and B.
Add 1 ml saliva in test tube A and leave both test tubes undisturbed for 20-30 minutes. Now add a few drops of iodine to both the test tubes.
The colour of iodine does not change in the test tube A as starch is converted to sugar by enzymes present in saliva.
The colour of iodine changes to blue-black in test tube B because it contains only starch solution.
[Note: If quantity is not mentioned do not deduct marks]
(or any other activity)
(b) (1) Bile changes the acidic medium of food to alkaline medium so that the pancreatic enzymes can act on it.
(2) It also emulsifies fats. / Breaks down the large fat globules into smaller particles. (any one)