SKHS Science Dept.
Honors Biology Common Lab
Name:___________________________________
Date:____________________
Honors Biology: Inquiry Enzyme Lab
Background: What would happen to your cells if they made a poisonous chemical? You might think that they would die.
In fact, your cells are always making poisonous chemicals. They do not die because your cells use enzymes to break
down these poisonous chemicals into harmless substances.
Hydrogen peroxide is a poisonous chemical that is produced by your cells during “normal” daily activity. “Catalase is a
common enzyme found in nearly all living organisms that are exposed to oxygen, where it functions to catalyze the
decomposition of hydrogen peroxide to water and oxygen.[1]Catalase has one of the highest turnover numbers of all
enzymes; one molecule of catalase can convert 40 million molecules of hydrogen peroxide to water and oxygen each
second.[2]” (http://www.princeton.edu/~achaney/tmve/wiki100k/docs/Catalase.html)
“Catalase is present in all body organs being especially concentrated in the liver & erythrocytes (=red blood cells).”
http://www.doctorslounge.com/primary/articles/antioxidants/antioxidants10.htm
The reaction is as follows:
(catalase) + 2H2O2  2H2O + O2 + (catalase)
(Hydrogen peroxide yields water and oxygen)
SAFETY:
Wear goggles when working with H2O2 solution.
All pieces of liver should be thrown in plastic trash bag.
H2O2 can be rinsed down sink.
QUESTIONS:
A. What happens when liver (containing catalase) is added to hydrogen peroxide?
B. Can the catalase in the liver be reused?
C. What is the effect of temperature on the catalase found in the liver?
D. Can more than one type of enzyme be used to break down H2O2?
E. What is the effect of pulverizing the liver before adding it to the hydrogen peroxide?
MATERIALS:
3% Hydrogen peroxide solution
Stirring rod
Test tube rack
Fresh liver and Boiled liver
Forceps (tweezers)
Test tubes
Graduated cylinder
Ice
Lactase solution
Sand
Mortar and pestle
Hot plate for water bath
USE GRADUATED CYLINDER FOR MEASURING HYDROGEN PEROXIDE IN ALL EXPERIMENTS
Procedures:
1. Procedures for Part A: Normal catalase reaction
a. Place 2 ml of hydrogen peroxide into a clean test tube. Look at the hydrogen
peroxide. Is it bubbling? Observe and record.
b. Take a small piece of liver and add it to test tube.
c. Push the liver into the test tube. Observe and record rate of reaction.
2. With your group write a hypothesis and plan a simple experiment for each of the
questions in B-F . Write out your steps. Use the materials shown above.
3. Create an appropriate data table for the experiments.
Observations:
Note the speed of all reactions
on a scale of 0-5.
0 = no reaction
5 = very fast reaction
Assume the reaction in Part A
--c. reacts at a speed of “4”.
SKHS Science Dept.
Honors Biology Common Lab
Name:___________________________________
Date:____________________
Honors Biology: Inquiry Enzyme Lab
SUBMIT: FORMAL LAB REPORT
Introduction –
 Purpose of experiments. (Paragraph 1)
 Background information: What is an enzyme? How do they function? Where are they found? Include all of the
information that is necessary to support the hypotheses you will be making. (Paragraph 2)
 Hypothesis – You are examining six different questions in this lab. (See above). Write a hypothesis for each of
the questions being studied. In other words, “If (what you will do) then (what do you think will be the results of
the experiment?)” Use your class notes, internet and Biology textbook to help you with this. For example: “If a
small piece of liver is placed on ice then …” (Paragraph 3)
Materials Bulleted list of materials (one list for all of the experiments together)
Procedures –
 Use class procedures (these will be shared by groups)
 Write the procedures step by step and number each step.
 Include all of the quantities and the amounts of time.
 Ask yourself: Can someone else follow your procedures and conduct the exact same experiment?
Data Table(s) – Typed or use ruler to draw
 Give the table a title
 Accurately label each column in your data table
 Use accurate units on your data table
Analysis and conclusions  Simply restate problem and hypotheses: (Paragraph 1)
o What did you find?
o Does your data support each hypothesis? Be specific. Cite the data!
o DO NOT explain WHY your hypotheses were correct or incorrect.
 Discuss your results: (Paragraph 2) Include at a minimum:
o What were the bubbles made of in this experiment?
o Part A-C: Explain why you had the results you did for each of these experiments.

Discuss: (Paragraph 3)
o Part D-F: Explain why you had the results you did for each of these experiments.
o Why is catalase concentrated in erythrocytes?
o Explain the lock and key analogy of enzyme and substrate. How does it apply to the experiments you
conducted?
 Discuss: (Paragraph 4)
o How could the experiments have been improved? Do NOT say something like “the materials should
have been better measured or the glasswares should have been better cleaned.”
o What further questions for study do these experiments raise?
SKHS Science Dept.
Honors Biology Common Lab
Name:___________________________________
Date:____________________
Honors Biology: Inquiry Enzyme Lab
Editing checklist
Lab report reviewed by:
______________
___________
and
Purpose:
 Refers to how enzyme function can be affected by the variables being tested: the same enzyme being used more
then once, various temperatures, increasing surface area, and substituting a different enzyme
Background information editing checklist:
 Explain definition of an enzyme.
 Naming the specific enzyme being used in the lab and describing the substrate and products
 Describing where the enzyme is typically found and why it is important
 Explains the effect of temperature on molecular motion and therefore the enzyme substrate complex
 Explains the effect of extreme heat on enzyme structure
 Explains the importance of enzyme specificity
 Explains the effect of changing the amount of enzyme available on reaction rate (relates to pulverized liver)
Hypothesis
 State all hypothesis for all parts.
 Includes the expected rate of reaction on scale of 0-5
Procedures and materials
 Numbered list
 Includes temperatures of water baths
 Includes the time left in the water baths
 Includes quanity of hydrogen peroxide to use
 The use of all materials on materials list is included somewhere in the procedures.
Data table
 Basic data table listing what is involved with each test
 Rate of reaction listed, optional: observations of each test
 Table has detailed title
Conclusion
 (Paragraph 1) Problem and hypothesis restated for each test. States whether hypothesis was proven correct,
incorrect, or inconclusive.
 (Paragraph 2)
o Explains what were the bubbles made of in this experiment?
o Part A-C: Explain why you had the results you did for each of these experiments.

(Paragraph 3)
o Part D-F: Explain why you had the results you did for each of these experiments.
o Why is catalase concentrated in erythrocytes?
o Explain the lock and key analogy of enzyme and substrate. How does it apply to the experiments you
conducted?
 Discuss: (Paragraph 4)
o How could the experiments have been improved?
o What uncontrolled variables could have affected your results. These should be problems that were
unavoidable. Do NOT say something like “the materials should have been better measured or the
glasswares should have been better cleaned.”
o What further questions for study do these experiments raise?
Format
 Works cited included, none of the report is plagarized. Quotation marks used when needed. Plagarized
sections will receive a zero!
 Avoided the use of personal pronouns. No “I”, “we”, etc.
 Sections in the correct order
SKHS Science Dept.
Honors Biology Common Lab
Name:___________________________________
Date:____________________
Honors Biology: Inquiry Enzyme Lab