Author: Joyce Buda


Final Applied Lab Project (1 credit Lab Component)
 Addresses course outcomes 1-4:
recognize and explain how the scientific method is used to solve problems
make observations and discriminate between scientific and pseudoscientific explanations
weigh evidence and make decisions based on strengths and limitations of scientific knowledge and the scientific method
use knowledge of biological principles, the scientific method, and appropriate technologies to ask relevant questions, develop hypotheses, design and conduct experiments, interpret results, and draw conclusions
This is the culminating lab assessment in BIOL 103. It is designed to assess your ability to apply the principles of the scientific method.
The Effect of low pH on Enzyme Activity
Design an experiment in which you will test the effect of an acidic fluid on enzymatic activity. Recall: enzymes are proteins! To complete this project, it may be useful for you to first review the Scientific Method Tutorial, the OLI module about pH and enzymes, Lab 1 (Introduction to Science) and Lab 4 (Enzymes).  As you review Lab 4, you will be reminded that there are several factors that impact enzymatic activity: pH, temperature, and amount of reagent. It is OK to use the same enzyme/substrate/method as you did in lab 4 (but modify the treatment), or you can search on-line to find a different enzyme/substrate/method for measuring enzyme activity for your project (include all references).
As you design your experiment for this project, please remember that you are trying to examine how an acidic fluid will modify the outcome of an enzymatic reaction.  To successfully complete this project, you will need to identify the question(s) being asked in your experiment and the hypothesis that you are testing.  In your experimental design, you must clearly explain what you are doing. That means that you will need to identify the enzyme, the substrate, the acidic fluid used as treatment, the control treatment and the method of measuring enzyme activity, as well as explain your experimental protocol.  You must also thoroughly explain how the acidic fluid impacted enzyme activity based on the results from your own experiment as well as knowledge of enzymes and pH from the OLI modules, lab manual and potentially additional information sources.
Hint: Keep in mind that the acid will change the environmental conditions of the experiment (for example, a low pH value could change the shape of the active site on the enzyme protein), without directly participating in the reaction.
Lab Materials
You may need all or some of the following, depending on your experimental design:
Materials from your lab kit:
pH paper
hydrogen peroxide solution (you can purchase this at a pharmacy if you have used up the bottle that came with the lab kit)
plastic beakers or cups
yeast (can be purchased at grocery store if more is needed)
plastic bottle
marker for labeling of beakers
You may choose to use additional materials (different acidic fluids and/or different organisms and/or different substrate if you chose an enzyme other than catalase).
Outline submit in assignment folder in week 5.
Include the following in your outline:
Name of enzyme you will use
Name of organism (if applicable)
The substrate
Method for measuring enzyme activity
Treatment: acidic fluid(s), pH, length of exposure, how you will treat your samples
The control(s) in the experiment
Sample size
How you will present your data (table and/or type of graph)
Anything else you would like to get feedback on before you start your experiment

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