JSSS Round 2
Student
Investigate the action of amylase on starch
OB8
Fact
Food is mainly made up of large molecules. Enzymes break down food into smaller molecules.
Amylase is an example of an enzyme; it is found in saliva and in the small intestine.
Investigation 1: Testing for sugar and starch
Apparatus
Starch solution, iodine solution, sugar solution, amylase solution, Clinistix, worksheet
Procedure
1.
2.
3.
4.
5.
Put a small quantity (three drops) of starch solution on A and B.
Put a small quantity (three drops) of sugar solution on C and D.
Test A and C for starch using one drop of iodine.
Test B and D for sugar using a Clinistix strip. (Note: dip the coloured tip of the Clinistix in
the liquid; remove and observe the colour change.)
Record any colour changes in the table.
Starch
Sugar
Colour with iodine
Colour with Clinstix strip
The colour of iodine changes to ________________ if starch is present.
The colour of the Clinistix changes to ________________ if sugar is present.
Investigation 2: To investigate the effect of amylase on starch
Procedure
1.
2.
3.
4.
5.
Put a small quantity (three drops) of starch on E, F, G and H.
Add three drops of amylase to E and F. Add three drops of distilled water to G and H.
Allow three minutes to pass and then test E and G for starch as in investigation 1.
Test F and H for sugar as in investigation 1.
Record any colour changes in the table.
Starch and amylase
Colour with iodine
Colour with Clinistix strip
-1-
Starch and water
JSSS Round 2
Student
Discuss the following questions and decide on an answer.
1. What did you use to test for starch?
2. What colour showed that starch was present?
_______________________________________________________________________
3. What colour showed that starch was not present?
________________________________________________________________________
4. What did you use to test for sugar?
________________________________________________________________________
5. What colour showed that sugar was present?
________________________________________________________________________
6. What colour showed that sugar was not present?
________________________________________________________________________
Fact
A control is when you set up a second experiment which is similar to the first one, except in one detail.
If you get a different result, then that detail must be the reason for the difference.
1. Was there starch present in E?
________________________________________________________________________
2. When amylase acts on starch the product is a
______________________________________________________________________
3. Why did you replace the amylase with water in G and H?
________________________________________________________________________
Fact
The substance on which an enzyme acts is called the substrate. The substance produced is called the
product.
1. What was the substrate in this experiment?
_______________________________________________________________________
2. What was the product in this experiment?
________________________________________________________________________
3.
Was this a fair test?
________________________________________________________________________
-2-
JSSS Round 2
Student
4. Explain your answer.
________________________________________________________________________
5. Where in the body is amylase found?
_________________________________________________________________________
6. What have you learned about amylase from this experiment?
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
Investigation 1
A
Starch
B
Starch
C
Sugar
D
Sugar
-3-
JSSS Round 2
Student
Investigation 2
E
Starch and Amylase
F
Starch and Amylase
G
Starch and Distilled Water
H
Starch and Distilled Water
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