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 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.
- 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.
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