Addresses course outcomes 1-5:

· apply the scientific method to scientific investigations

· state a scientific hypothesis and design a basic experiment

· conduct an experiment, make observations, and collect data

· use knowledge of biological principles to correctly interpret qualitative and quantitative information

· use critical analysis to draw conclusions

This is the culminating assessment in BIOL 102. It is designed to assess your ability to apply the principles of the scientific method. For this project, you will complete the activity below. Make sure to address all points (questions) associated with the activity.

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 review the Scientific Method Tutorial (found the Course Content section of the classroom under the Science Learning Center link) and the Scientific Method lab (Lab 1), so that you can better understand how to design an experiment. It may also be helpful for you to review your textbook 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. Feel free to refer to observations and information from Lab 4 as you complete the Final Applied Project (see the questions below). Or in other words, 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.

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 your hypothesis, the enzyme and the acid, as well as explain your experimental protocol (this information will help you to answer question 2). You must also thoroughly explain how the addition of the acidic fluid impacted the overall reaction process (this information will help you to answer question 4).

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

· vinegar

· yeast (can be purchased at grocery store if you need more)

· balloons

· plastic bottle

· marker for labeling of beakers

You may choose to use additional materials (different acidic solutions and/or different organisms and/or different substrate(s) if you chose to look at an enzyme other than catalase).

Part 1: Submit Your Experiment Outline to Your Assignment Folder
Include the following in your outline, numbered, in order (your project outline will be returned to you and/or feedback delayed if any of the below are missing):

1. The hypothesis you are testing. You have three options here - choose one to test in your experiment:

"Acid will decrease enzyme activity," or,
"Acid will not affect enzyme activity," or,
"Acid will decrease enzyme activity."

2. Name of enzyme you will use, and its source (organism, if applicable).

3. The substrate in your experiment

4. What type of acid treatment you will use; type of solution(s), pH, length of exposure, how you will treat your samples. An acid is a substance with a low pH (less than 7). Examples of common household acids that you might choose to test in this experiment include acetic acid (vinegar), citric acid (e.g., lemon juice, orange juice, tomato juice), tannic acid (tea); citric and/or phosphoric acid (found in soft drinks, cola). There are other acids, however, please do not attempt to use battery acid, sulfuric acid, or hydrochloric acid in this experiment.

5. The experimental treatment setup (the setup with the acid treatment: acid + enzyme+ substrate -> product)

6. The control(s) in the experiment (setup without the acid treatment: enzyme+ substrate -> product)

7. How you will measure enzyme activity (method; e.g., how will you know if the enzyme is "working" or not? What will be the measurable product of the enzyme reaction?)

8. Sample size for each group (treatment and control)

9. How you plan to present your data (data table and type of graph)

10. Anything else you would like to get feedback on before you start your experiment. Make sure to read the feedback for your outline before proceeding with your experiment!

· Note: You are required to develop your outline and perform the experiment using your own work and to write your project lab report in your own words. Your project will be checked for plagiarism.