Lab Group Member Names:
____________________________ ____________________________
____________________________ ____________________________
Date: _______ Period: _____
Bean Amylase Lab
Investigating the Effects of Temperature, pH and Salinity on Enzyme Activity
Science Background:
You may be surprised to learn that the amylase enzyme is produced by a variety of living organisms, ranging from
bacteria to plants and humans. You may be even more surprised to learn that the amylase enzyme has the same
function in beans that it has in humans…to break down starch (carbohydrate). Why would bacteria, plants, and
animals have the same enzyme??? Beans are seeds in their dormant state. The dried beans in your kitchen
cabinet at home are living organisms in a dormant state with a food source (carbohydrate and lipid). Once water
is available to break their dormancy the beans will germinate. Try this at home: take 10 dried beans and place
them between damp paper towels in a room temperature environment then check them 24 hours later. What
happens?
The ENZYME Amylase breaks down starch very, very quickly! Here is the reaction:
Starch (carbohydrate)    glucose + glucose (monosaccharides)
(amylase)
Like all ENZYMES, the shape of Amylase is sensitive to changes in pH, salinity, and temperature, which can
denature these protein molecules. Many enzymes in the human body function most efficiently at 37oC and at a pH
of 7.4.
In this lab we’ll investigate how changing the pH, salinity, and temperature of Amylase affects its ability to break
down starch (carbohydrate). We can measure how effectively the enzyme is working by making qualitative
observations about the color change in the chemical reaction that occurs when amylase breaks down starch and
turns the starch iodine solution from blue/black to clear.
Prior Knowledge, after reading Science Background above:
What do you already know about Enzymes?
List three things that you’ve learned about enzymes this week.
What do you already know about Amylase?
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Bean Amylase Lab – Enzyme Action!
Purpose : Find out if Amylase is affected by changes in their environment.
Experimental Questions: Do changes in pH, temperature, and salinity adversely affect the ability of Amylase to
break down starch?
Prediction: Write the word(s) will or will not on blank line for each of the conditions below:
A. I predict that the enzyme Amylase __________________________________ break down starch
in an acidic environment.
B. I predict that the enzyme Amylase __________________________________ break down starch
when the temperature has been raised to boiling.
C. I predict that the enzyme Amylase __________________________________ break down starch
in salt solution.
Materials:
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Safety glasses
12 well plate
1 pipet
Acid in labeled dropper
30% Salt in labeled dropper
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Starch + Iodine in labeled dropper
Bean Amylase (ENZYME) in labeled
bottle
Boiled Bean Amylase (ENZYME) for class
Procedure:
1. Put on safety glasses.
2. Neatly organize all materials at your work station.
3. Follow the diagram below to do each part of this experiment in triplicate. Add chemicals to the well in the
order given.
**Notice that the boiled bean amylase has
4. Record final color in each circle below.
turned orange due to being boiled. If the
enzyme is still active, the blue starch/iodine
mixture will turn orange, not clear.
PART A - CONTROL ROW:
10 drops bean amylase (ENZYME)
1mL distilled water
1mL starch + iodine
PART B - TEMPERATURE EFFECT ROW:
10 drops boiled bean amylase (ENZYME)
1mL distilled water
1mL starch + iodine
PART C - pH EFFECT ROW:
10 drops bean amylase (ENZYME)
10 drops 1M HCl (acid) wait 2 minutes before proceeding
1mL starch + iodine
PART D - SALINITY EFFECT ROW:
10 drops bean amylase (ENZYME)
10 drops 30% salt wait 2 minutes before proceeding
1mL starch + iodine
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Analysis Questions: Answer in complete sentences.
1. Define: Denatured:
2. Was amylase completely denatured in any of your experimental reactions? Circle one: Yes / No
a. If so, which one(s)?
b. What is your evidence? (data)
3. What is the Manipulated Variable in this lab?
4. Name at least 3 Controlled Variables in this lab.
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5. What is the enzyme in this chemical reaction in this experiment?
6. Define substrate:
7. What is the name of the substrate in this chemical reaction?
8. Describe in your own words what the enzyme is doing in this chemical reaction.
9. Why are enzymes important to living things?
10. Enzymes are catalysts, what do catalysts do?
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Name: _________________________________
Date:____________________
Period:______
Enzyme Diagram
Instructions: illustrate the digestion reaction that occurred in this lab. Label the following in your
drawings enzyme, substrate, enzyme substrate complex, active site, reactants, products. Provide a short
written summary in each panel.
Normal Reaction
Before (Reactants)
During (Reaction)
After (Products)
Denatured Reaction
Instructions: illustrate the same reaction above, but show a denatured enzyme in a digestion. Label the
following in your drawings enzyme, substrate, enzyme substrate complex, active site (specify in your
illustration what is happening here, reactants, lack of products (no product will be formed). Provide a
short written summary in each panel.
Before (Reactants)
During (Reaction)
After (Products)
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Write a conclusion for this experiment. Include all of the following words: enzyme, amylase, substrate, denature,
catalyst, activation energy, active site, reactants, products.
In your conclusion, be sure to:
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Answer the experimental question.
Include supporting data from the qualitative observations.
Explain how these data support your conclusion.
Provide a scientific explanation for the phenomenon that you observed
Question: What is the effect of the different environmental changes on the amylase’s ability to break
down starch?
Conclusion:
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