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Date:
Period:
Amylase Lab
Background Information:
Enzymes are present in all living cells. Our bodies contain many different
enzymes. One enzyme that is used everyday is amylase. Amylase is found
saliva and it is responsible for breaking down carbohydrates.
Starch is a large molecule commonly found in foods such as grains,
potatoes, and pasta. Essentially, it is a very complex form of sugar. For our
bodies to use starch, it must be broken down into smaller, simpler sugars. A
common simple sugar is known as glucose.
In our mouths, the amylase that is found in saliva actually begins the break
down of starch into glucose.
Have you ever eaten a piece of bread or a cracker slowly and allowed it to
dissolve in your mouth? You may have noticed a faint sweet taste or
sensation. This is actually because your spit is breaking down the starch from
the grains into a sugar! Try it!
Purpose:
- To determine the effects of high temperatures on enzyme activity.
- To determine that amylase breaks down starch into sugar.
Materials:
Safety goggles
Starch solution
Test tubes (6 per group)
Test tube rack
Benedict’s solution
400 ml beaker
Iodine solution
Bunsen burner
Amylase solution (or your own spit – you choose!)
Information about the solutions:
Starch solution: This is going to symbolize the grain food that we eat. Think
of the starch solution as a piece of bread or a cracker
Iodine solution: This is used as a starch indicator. Iodine changes color to a
dark blue/black when it comes into contact with starch. Therefore, it lets us
know if starch is present in a solution
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Benedict’s solution: This is used as a glucose indicator. Benedict’s solution
changes color to a reddish/pink when it comes into contact with glucose.
Therefore, it lets us know if glucose is present in a solution. In order to work
properly though, Benedict’s solution must be warmed up using a warm water
bath
Amylase solution: This represents the enzyme found in your own spit that is
responsible for breaking down starch into glucose. You may use this solution,
or, if you would like to be more realistic, try using your own spit instead
Procedures:
Part 1: Testing the enzyme to see if it works
(Complete the data table of observations as you go.)
A: Test for Starch:
1. Obtain 4 test tubes and label them “Test Tube 1”, “Test Tube 2”, “Test
Tube 3” and “Test Tube 4”
2. Pour approx 10 drops of starch solution to each of the test tubes
3. In “Test Tube 1” and “Test Tube 2”, add an additional 10 drops
(approx) of amylase solution (or your own spit). Mix them well by
flicking the test tube. Allow them to marinate while you proceed to
step 4.
4. In “Test Tube 3”, test for starch by adding one drop of the iodine
solution.
5. Repeat step 4 for “Test Tube 1”. You are now finished with “Test Tube
1” and “Test Tube 3”
Sample
Contents
Test Tube 1
Test Tube 3
starch
Starch and amylase
Reaction with Iodine
(indicate color change)
No colour change
Blue/black
B: Test for Glucose:
6. In “Test Tube 2” and “Test Tube 4”, add approx 5 drops of Benedict’s
solution.
7. One at a time, carefully place “Test Tube 2” and “Test Tube 4” into a
warm water bath.
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Date:
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Sample
Contents
Test Tube 2
Starch and amylase
Test Tube 4
Starch
Reaction with Benedict’s
solution (indicate color
change)
Yellow/orange/pink
No change
Part 2: Effect of Temperature
1. Obtain 2 test tubes and label them “Test Tube 5” an “Test Tube 6”
2. Pour approx 10 drops of starch solution into both test tubes.
3. In a separate test tube, pour a small amount of amylase solution (or your
own spit). Boil this test tube using the hot water bath.
4. Add your boiled amylase/spit solution to “Test Tube 6”.
5. Test both test tubes for starch by adding a drop of iodine solution to each.
Sample
Contents
Reaction with Iodine
(indicate color change)
Test Tube 5
starch
Test Tube 6
Starch and boiled
amylase
Blue/black
Blue/black
Concluding Questions:
1. Biochemists write the relationship among substrate, enzyme and product
with the equation:
enzyme
Substrate -----------> product
Write this equation using the substrate, enzyme and product of this amylase
lab. (3 marks)
amylase
Starch ------------- Glucose
2. List three things that will denature an enzyme. (3 marks)
Heat, high acidity, high alkaline (basic)
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Date:
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3. In part 2 of the experiment, what happened to the amylase enzyme when
it was boiled? Did it still work? What is happening to the active site? (3
marks)
The enzyme was denatured, no it did not work because starch was still
detected. The active site is being changed so that the substrate can no
longer bind.
4. The temperature inside the human body where enzymes can function is
36.6°C. What might happen if a person has a fever of 40°C or higher? (2
marks)
The enzymes would denature and not work properly because the substrate
would no longer bind to the active site.
5. What was the purpose of adding the iodine solution and Benedict’s solution
to our test tubes? (2 marks)
Iodine: detects starch
Benedict’s detects glucose