3rd

Name: Geofrey Jinuin

Class: 3 Melati

Aim

: To show the action of salivary on starch

Material

:1% starch solution dilute saliva solution, iodine solution, benedicts solution, distilled water.

Apparatus

:Beaker, test tube, tripod stand, wire gauze, Bunsen burner, stopwatch, glass rod, water bath at 37°c, thermometer.

Procedure.

1. 5cm of 2% starch solution is poured into test tubes ! and B respectively. The contents are tested for starch glucose. A students is asked to wash his mouth with tap water then some saliva is collect 3. 1cm of the saliva is added to test tubes A, and 1cm of distilled water is added to test tube B. 4. The contents of test tubes A and B are stirred 5. The test tube are left to stand in a water bath for several minutes. 6. The contents are again tested for starch and glucose 7. The result are shown in table 2.9 2.

Test Iodine solution Benedicts solution

Test tube A

Test tube B

Beginning

End

Beginning

End

Starch Glucose observe

Starch observe Glucose observe

Starch Glucose observe

Starch Glucose observe

Questions 1. 2. 3.

Why must you rinse your mouth with distilled water before collecting the saliva solution? -To ensure no bits of food are present in the saliva. Why must you place test tube into the water bath at 37°c? -To be kept at a constant temperature of 37°c What effect did your saliva have on the starch solution -A simple sugar is formed.

Conclusion Salivary amylase catalyses the breakdown of starch into the maltose( a kind of sugar)