Q3. You have been provided with two test tubes- A and B with Iml of starch solution each. You
have added 1ml of your saliva to test tube A and left both the test tubes undisturbed for an hour.
Next, a few drops of dilute iodine solution have been added to both the test tubes.
What will you observe?
Test Tube A- No change of colour on adding iodine
Test Tube B - Change of colour to blue black.
State the reason behind your observation.
Test Tube A- No change of colour on adding iodine indicates absence of starch
because iodine changes its colour to blue black if starch is present.
The starch in Test Tube A was broken by down the enzyme salivary amylase present
in saliva to simple sugars glucose. Therefore there was no change in colour.
Test Tube B - Change of colour to blue black indicates the presence of starch as no
saliva was added to it.
Answers
Explanation:
yes!
it is an activity to prove the action of saliva on flour. test tube which is added saliva turns into blue black in colour when we add iodine solution to both of the test tubes we don't identify any change on test tube B.
start a solution contains carbohydrates and when we add saliva on it digest carbohydrates and when we add iodine solution in it it changes to blue black in colour . iodine solution able to test the presence of starch .
Answer
Saliva of man contains Ptyalin enzymes
Explanation:
(a) In test tube B a colour change is noticed
(b) Test tube B still contains starch. It is now absent in test tube A
(c) Since there is saliva in test tube A; the enzyme Ptyalin; converts the starch into disaccharide which do not give colour with iodine.
Hope it will help you