ZIMSEC O Level Combined Science Notes: Amylase enzyme experiment
Materilas: 1% amylase enzyme/saliva, 2% startch solution, visking tubing, reagents to test for starch and sugar, beakers.
Method A: Visking Tubing.
NB. The Visking Tubing is used to function/work as a small small intestine.
Prepare two model intestines by wetting the visking tubing.
Open the ends of the tube. Tie one end tightly with a string to make a bag like structure.
Add 5 to 10 ml of starch solution and the same amount of enzyme solution/or gurgle an amount of the solution and spit it into one tube and label it tube A.
Add only starch solution to the other and label it tube B.
Remove a small sample of the mixture for testing. Keep this to one side.
Was the outside of the bags carefully to remove ony of the solutions and make sure the bags are not leaking.
Support the bag in a small container of water or tie the other end tightly and immerse in water.
Test the content of the bag and the surrounding water for starch and reducing sugar at the start of the experiment.
Repeat after about 10-15 minutes.
Record the results.
Test tube A’s starch is converted into reducing sugars.
The starch in test tube B remains unchanged.
The contents of tube A are the right and Tube B on the left. Image credit studyblue.com
The results shown above are obtained after carrying out a test using Benedict’s Solution which is used to test for the presence of reducing sugars.
The contents of Test Tube A (to the right) show the presence of reducing sugars. The solution turns brick red in colour. This is because the enzyme amylase has acted as a catalyst resulting in starch being converted into reducing sugars.
The contents of Test Tube B show that the starch has remained unchanged.
The contents of tube A are to the right and those of Tube B above to the left. Image credit sites.google.com
When a test for starch is carried out using an Iodine solution the following results are obtained:
The contents of Test tube B turn blue-black as above and showing that the starch remains unchanged.
The contents of tube B above show that there is very little starch after the experiment as most of it has been turned into reducing sugars.
Amylase acts as a catalyst during the digestive process.
This results in the starch in food being turned into reducing sugars.