Download Salivary Amylase Lab

Biology
DNA → Proteins → Enzymes (polymers of amino acids with specific shapes)
Salivary Amylase Lab
Introduction (Quickly summarize this in your Research Journal)
The salivary glands secrete saliva. Aside from moistening the mouth, binding food particles together, and acting as a
solvent in order to dissolve food, the saliva also contains an enzyme. The enzyme is called salivary amylase and is
responsible for the chemical breakdown of starch (a polymer) into sugars (monomer) via the process of hydrolysis. In
order for salivary amylase to perform properly, conditions should be optimum. An enzymes action depends on its
shape. Extremes of temperature and pH may deform (denature) the enzyme. In this lab, you will work in groups of
four and test the effectiveness of salivary amylase under different conditions.
Problem (Copy this.)
Under which condition(s), boiling, cold, body temp., room temp., acid (low pH) or base
(high pH) will Salivary Amylase still function (break starch down into sugars)?
Materials
HCl (acid)
NaOH (base)
Benedict’s solution
starch solution
Protocol
graduated cylinder
2 beakers 100mL
9 test tubes
test tube rack
test tube holder
hot water bath
ice
2 beakers-250 mL
The procedure for this lab will be given in sequential steps. Be organized! You have only one block
period to complete this lab. In order to do this, we will need to use saliva from 2 individuals in your 4lab-partner group.
Saliva Test
Each Team needs two spitters to collect at least 20 ml of saliva in the first 20 minutes of class.
The saliva needs to be tested BEFORE collecting.
1. Label two test tubes 8 and 9.
2. Two spitters spit or drool 2-3mL into these test tubes.
3. Add 20 drops of Benedict’s solution to both test tubes.
4. Heat in boiling water bath for 4 minutes and check for change of color indicating sugar.
Liquid should stay blue for 4 minutes. If it changes to green or orange select a new spitter.
(Keep tubes 8 & 9 until the end of the lab) Clean spitters collect at least 20mL of saliva in the 100mL
beakers.
Salivary Amylase Lab
1. Each team needs 9 test tubes labeled 1 – 9. (Keep tubes 8 & 9 from Saliva Test)
2. Add 2 to 3 ml of saliva to test tubes 1- 6. (no saliva in #7)
3. Add 20 drops of HCl to test tube # 3.
4. Add 20 drops of NaOH to test tube # 4
5. Fill a 250 mL beaker with ice and water. Place test tube #1 in the beaker for 10 minutes.
6. Fill a 250 mL beaker with hot water from the tap (sink). Place test tubes #2, 3, and 4 in the
beaker for 10 minutes.
7. Place test tube #5 in a beaker with boiling water for 10 minutes. Move to step 8 while waiting.
(Leave test tube #6 in the rack at room temperature.)
8. Write a hypothesis (If, then, because statement) that attempts to answer the Problem.
Note: You are testing the Salivary Amylase enzyme under the following conditions:
a. Cold: 5 degrees centigrade.
b. Heat: 100 degrees centigrade
c. Acid: HCl
d. Base: NaOH
e. Body temperature (hot tap water): 37 degrees centigrade
f. Neutral pH: no acid or base
g. room temperature: 20 degrees centigrade
***CHECK POINT 1: GET A SIG FOR YOUR HYPOTHESIS.
9. Construct a data table similar to the sample data table. (Use a ruler.)
10. After tubes have been in water baths for 10 minutes: add 20 drops of starch solution to all test
tubes Except #s 8 & 9 and place in rack for 5 minutes. (Test tubes 8 & 9 were completed during
the Saliva Test.)
11. After 5 minutes: add 20 drops of Benedict’s solution to all the test tubes except 8 & 9. (Test
tubes 8 & 9 already have Benedict’s from the Saliva Test.)
12. Heat tubes 1-7 in boiling water bath for 4 minutes and check for color change indicating sugar.
Orange = positive
Green = slightly positive
Blue = negative
13. Add this data to your data table.
Test Tube #
Temperature
Acidity
Manipulated
Variable
Color
+ or - Sugar
1
2
(Keep all 9 tubes until signed off!)
3
4
5
6
7
8
9
SAMPLE
***CHECK POINT 2: BE SURE TO GET SIG BEFORE YOU EMPTY OUT YOUR TEST TUBES!!!!!!!
(Rehearse: Your group will have to explain what is being shown by each test tube.)
Wash all test tubes and beakers and other equipment with detergent. Wash down your table.
***CHECK POINT 3: CLEAN UP YOUR TEST TUBES AND STATION AND GET A STAMP!!
Questions: Copy questions and answer them in your journal.
1. What was the purpose of this lab activity?
2. What are 3 functions of saliva?
3. What substrate specifically fits the enzyme, Salivary Amylase?
4. What was the significance of 37 degrees Celsius in this lab activity?
5. What was the purpose of test tube #7? (Explain)
6. What was the purpose of test tubes 8, and 9? (Explain)
6. Which test tube # most closely resembled the conditions in the human mouth? (Explain)
7. Why leave the tubes of saliva in the water baths for 10 minutes prior to adding the 20 drops of starch?
8. Why leave the starch in the tubes of saliva for 5 minutes prior to adding the Benedict’s solution?
9. Explain what conditions in this lab activity most affected the ability of Salivary Amylase to function
properly.
Conclusion:
Write a 3-part conclusion that addresses your lab results for each hypothesis.