NAME:______________________________________________________
IB Biology Lab Virtual Investigation
AIM: Experimental investigation of a factor affecting enzyme activity. (Practical 3)
Part One: Background Reading & Virtual Inquiry 1
1. Read Topic 2.5 Enzymes on pages 80-85 in EText Topic 2 Molecular Biology (on Wiki)
2. Visit the following website:
a. http://www.phschool.com/science/biology_place/labbench/lab2/intro.html
b. Read and watch the INTRODUCTION and KEY CONCEPTS.
3. Define the following terms using your own words:
a. Catalyze:
b. Enzyme:
c. Activation Energy:
d. Substrate:
e. Product:
f.
Active Site:
g. Denaturation:
4. What are two factors given in the virtual lab that may affect enzyme function?
5. Explain how do the two factors listed previously have their effect?
6. What is one additional factor that might affect enzyme function?
7. Explain how would this additional factor have its effect on enzyme function?
Part Two: Virtual Experiment - The effect of pH and substrate concentration on enzyme function
Visit the following website:
http://glencoe.mheducation.com/sites/dl/free/0078759864/383930/BL_11.html
In this inquiry you will be conducting an experiment to explore the effect of a) ph and b) substrate
concentration on enzyme function. To do this you will create an experiment, conduct a series of trials,
and collect data to determine the effect on enzyme function. You will collect data for each experiment.
You should record you data in Excel/Sheets and use the graphing function to create the graph of your
results. (Do not use the table and graph function in the website). Begin by watching the video about
enzymes (click on the TV). Follow the instructions on the left side of the screen.
You must test enzyme function at 5 different levels of pH (3,5,7,9,11) and with 5 different
concentrations of substrate (.5,1,2,4,8g). You should record the “Number of Molecules of Product
Formed in One Minute (x106)” as your data.
Before beginning the experiment you should complete the following:
1) Based on the previous readings and activities, make separate predictions about what will be the
effects of a) increasing pH and b) increasing substrate concentration on enzyme function. Be sure to
provide an explanation for why you have made these predictions.
a) increasing pH:
b) increasing substrate concentration:
2) Create a spreadsheet in Excel or Google Sheets that will allow you to analyze the data to interpret the
effect of both increasing pH and increasing substrate concentration on the enzyme function. You should
have the data table set up in such a way as making the graph is a simple task. You MUST save the
Excel/Sheet as “yourname_Practical3_VirtualEnzymeLab” and share it or upload it to the shared folder,
“Practical 3 Enzyme Lab”.
3) Once you have completed these steps you should begin to carry out your virtual experiment. You
should write out your steps below, including any relevant information concerning your groups,
treatments, or trials. All data collected should be recorded into your Excel/Google Sheet.
4) Once you have collected your data and recorded it in a spreadsheet, you should create two graphs.
One should show the effect of increasing pH on enzyme activity for all substrate concentrations. The
second should show the effect of increasing substrate concentration on enzyme activity for all pH levels.
(The data set is the same for both, what is different is the way you present the data).
5) Using the graphs that you have created, complete the following:
a) Briefly describe the overall effect of increasing pH on enzyme activity. Did your results match your
initial predictions? How does this relate to DIGESTION?
b) Briefly describe the overall effect of increasing substrate concentration on enzyme activity. DO your
results match your initial prediction? How does this relate to DIGESTION?
6) How could you test for the effect of temperature on enzyme activity? Outline an experiment that
would allow you to test for the effect of temperature, be sure to include clear statements of your
independent, dependent, and controlled variables and including all your treatment groups.