SKHS Science Dept.
Biology Common Lab
Name:___________________________________
Part 1
Date:____________________
Inquiry Enzyme Lab
Purpose: The purpose of this portion of the lab is to design and perform an experiment to test
the function of a specific enzyme, lactase (in solution), when exposed to various sugar
solutions.
Background Information: Use the following information (with the list of materials) to design your
experiment.



Lactase: enzyme that breaks down lactose
Lactose: sugar (a disaccharide) found in milk
o composed of glucose and galactose
Sucrose: common table sugar (a disaccharide)
o composed of glucose and fructose
Remember:
-ose = sugar
-ase = enzyme
Hypothesis:
Materials: Each group must design an experiment using the following materials:
 lactase tablet
 10 ml graduated
 test tube rack
 milk
cylinder
 glucose test strips
 water
 beakers
 stirring rods
 sucrose
 test tubes
 timer
Procedure:
Remember:
You need a control!
Data: Create a data table to record your data.
SKHS Science Dept.
Biology Common Lab
Name:___________________________________
Part 2
Date:____________________
Inquiry Enzyme Lab
Purpose: The purpose of this portion of the lab is to design and perform an experiment to test
the effects of temperature on the function of enzymes.
Hypothesis:
Materials: Each group must design an experiment using the following materials:
 lactase tablet
 test tube rack
 milk
 glucose test strips
 10 ml graduated cylinder
 stirring rods
 beakers
 sucrose solution
 test tubes
 ice
Procedure:
Data: Create a data table to record your data.
GSE: LS1-1a: Students demonstrate understanding of structure and function by explaining the relationships
between and amongst the specialized structures of the cell
SLE: 1 (inquiry + lab report)
SKHS Science Dept.
Biology Common Lab
Name:___________________________________
Date:____________________
Inquiry Enzyme Lab
Teacher Instructions:
Leading students to the correct procedure (guided questions):
DAY ONE  PART ONE:
WHOLE GROUP: ~5 min.
1. Read through the purpose with students highlighting that the sugars and lactase tablet
are in solution.
2. Go through background information highlighting that lactose and sucrose are
disaccharides (explain what that means and what they break down into – both break
down into glucose as a component).
3. “If we’re testing enzyme function what are we testing for?”  A chemical reaction…How
do we test for it? *timers are only used for enzyme exposure not as data points!
LAB GROUPS: ~15 min.
4. Have students work in their lab groups to discuss how they would set up the experiment
and what data tables they would use. If students are having difficulty…Have them draw
the setup and then put it into words.
5. Circulate and ask guiding questions. “How do you know the reaction occurred?” “What
is your evidence?”  will be a common response.
WHOLE GROUP: ~5 min.
6. Make sure each group understands that we are looking for the chemical reaction of
sugars breaking down into glucose because of the enzyme AND the test strips are used
to prove the reaction occurred.
7. Teacher gives the amounts to use to make each solution.
DAY ONE  PART TWO:
WHOLE GROUP: ~ 5 min.
1. Read through the purpose with students highlighting that we are changing the
temperature of the enzyme solution.
2. Hypothesis – “How does changing the temperature of the enzyme solution affect the
breakdown of the 2 sugar solutions?” Explain that the procedure is essentially the same
as part one but they have to figure out how they are to change the enzyme solution.
LAB GROUPS: ~15 min.
3. Have students work in their lab groups to discuss how they would set up the experiment
and what data tables they would use. If students are having difficulty…Have them draw
the setup and then put it into words.
WHOLE GROUP: ~5 min.
4. Teacher gives the amounts to use to make each solution.
5. Prep students to be ready to complete the experiment as soon as they walk in the next
day!
DAY TWO: RUNNING THE EXPERIMENT
 Make the heated enzyme solution and the iced enzyme solution ahead of time (+30
minutes before class to denature the enzyme) to save time.
SKHS Science Dept.
Biology Common Lab
Name:___________________________________
Date:____________________
Inquiry Enzyme Lab
Solution Preparation
1. Enzyme stock solution: Add 1 lactase tablet to 200 ml of water. Stir until the tablet is
dissolved. (MAKE 3 TOTAL  enough for 6 groups of 4)
2. Sucrose solution: Add 5 grams of sugar to 100 ml of water. Stir until the sugar is dissolved.
(STUDENTS MAKE THIS)
3. Heated Enzyme solution:
a. Place 20 ml of enzyme solution into a test tube.
b. Add 200 ml of water to a 400 ml beaker.
c. Place the test tube in the beaker (gently laying the test tube so it rests on the side
of the beaker).
d. Boil the water in the beaker for 30 minutes.
e. Let the solution cool to room temperature.
4. Iced Enzyme solution:
a. Make a stock enzyme solution pour 20 ml into test tubes (one for each lab station).
b. Place into a 400 ml beaker filled with ice at each lab station for 30 minutes.
Procedure
1. Gather materials.
2. Label the test tubes with the following labels:
a. Milk & enzyme solution
b. Sucrose solution and enzyme solution
c. Water (control)
d. Milk and Heated enzyme solution (FOR PART 2)
3. Time each mixture for 2 minutes before testing with a glucose strip to ensure enough time
for the reaction.
Table 1: Amounts to add (students determine what solutions to use…teacher gives amount)
PART ONE:
Milk & enzyme solution
2 ml of milk
1 ml enzyme solution
Sucrose & enzyme solution
2 ml of sucrose solution
1 ml of enzyme solution
Water (control)
3 ml of water
PART TWO:
Milk & heated enzyme solution 2 ml of milk
1 ml heated enzyme solution
Milk & iced enzyme solution
2 ml of milk
1 ml iced enzyme solution
SKHS Science Dept.
Biology Common Lab
Name:___________________________________
Date:____________________
Inquiry Enzyme Lab
*Please visit the following website to read about lactose, lactase, and the genetics of lactose
intolerance. You will need the information to answer some of the analysis questions below.
http://www.indiana.edu/~ensiweb/lessons/tp.milk3.html
Analysis Questions:
(Answer the following questions in PARAGRAPH FORM in the conclusion section of your lab
report)!!! DO NOT FORGET TO INCLUDE ALL ASPECTS OF A PROFICIENT CONCLUSION SECTION!
1. What type of sugar is found in milk?
2. What two monosaccharides make up this sugar?
3. What is the difference between lactase and lactose?
4. What is lactose intolerance?
5. How was the presence of glucose tested?
6. What was the purpose of testing the water and enzyme solution?
7. What were your results of Part 1? Part 2? (BE SURE TO INCLUDE YOUR EVIDENCE!)
8. Did the enzyme break down sucrose? Why or why not?
9. What was the result of mixing the boiled enzyme with lactose? Explain.
10. Diagram and describe the lactose and lactase reaction. Label the reactants, products,
and enzyme. Why is this called the “lock and key” model? Explain.
SKHS Science Dept.
Biology Common Lab
Name:___________________________________
Date:____________________
Inquiry Enzyme Lab
PLEASE DO NOT USE PERSONAL PRONOUNS (NO “I”, “WE”, “OUR”, ETC.). MAKE SURE SENTENCES ARE
CLEAR, CONCISE, AND COMPLETE!
Introduction
For this section of the lab report answer the following questions in paragraph form:
 What is the purpose of this lab? Give enough background information on the lab topic to explain
it fully. (Example = Enzyme function background information)
 What is the question you are answering? (If there are multiple parts to the lab make sure to
address each section)
 What is the hypothesis? (If there are multiple parts to the lab make sure to address each section)
Materials
 Please bullet the materials list
Procedures
1. Please number the steps in the procedure.
2. Each step must be a complete sentence.
Data and Observations
 All tables must have a title (example - Table 1: Sugar/Starch Solution Data), labeled units, and
must make sense!
 All graphs must have a title (example - Figure 1: Sugar/Starch Solution Data), labeled units, a key,
and must make sense!
 If calculations were needed (example: calculating change in mass) give one example.
Conclusion/Discussion
For this section of the lab report answer the following questions in paragraph form. Do not forget to
address each bullet!!!
 Restate the purpose and hypothesis.
 How does this lab tie into what you are learning in class?
 Was your hypothesis correct? What does your data tell you? Make sure to talk about the
conclusions you reached as a result of your data. Support your conclusions with evidence!!!
o This is the section where you would include any analysis questions from the lab!!!
o Make sure to write these in paragraph form!!!
o You will not be proficient if the answers are numbered OR not in complete sentences!!!
 What could be some sources of error in your experiment?
 What can you do to improve the experiment if you were to do it again?
 What extra/new questions were generated that would lead to a deeper understanding of the
topic?