Enzyme Activity Computer Simulation Purpose: To identify the effects of changing pH and temperature on enzyme activity, identify the optimum pH and temperature for various enzymes, and compare those values. Materials: computer, Internet resources Procedure: 1. Go to the textbook website – www.mhhe.com/maderinquiry10/. 2. Select student edition from the bottom left of the screen. 3. Select “BioLabs” from the left-hand menu. 4. Select the link in the middle of the screen: “BioLabs: Interactive Laboratory Simulations.” 5. Select the 5th labs in the left-hand column, “Enzyme Kinetics.” 6. Click the “continue” button at the bottom right of the screen. 7. Read the information in the left-hand box. On #1 of your data sheet, make a general prediction about the effects of pH and temperature on enzyme activity. Then hit continue. 8. Before experimenting with the specific enzymes, you need to be familiar with how the program works. For that, you will work with the control enzyme first. At the top left, click on the arrow beside where it says “select an enzyme.” Select the control enzyme. 9. Enter the control temperature of 37 degrees, and the control pH of 7.0. Click on “graph data.” 10. Staying on the same screen, change the temperature to 90, click on “graph data.” Change the pH to 8, click on “graph data.” Change the pH to 6.5, click on “graph data.” Repeat with different conditions until you have a total of 6 trials. Observe your graphs, and answer #2 on your data sheet. 11. Hit the continue key twice. Read the information under “observations,”then advance to the next screen with a graph - it should say “Calf Intestinal Phosphatase pH Optimization I” at the top. You will need to select the calf enzyme from the “select enzyme” button at the top left. 12. Before you input any data, make a prediction about what temperature(s) and pH level(s) you think this enzyme should work best at. Record your prediction on #3 on your data sheet. 13. Enter a temperature from the medium range (30-50 degrees), and a pH value from the low range. Click on “graph data.” Then, keeping the temperature the same, enter a pH value from the medium range, click on “graph data.” Then do the same for a pH range from the high range. Repeat this up to 6 times, varying the pH. This should give you a range within which the pH seems to work best. If this data does not give you an optimum pH range, hit “clear data,” and enter more values (with the same temperature used before) until you feel you have a satisfactory range to work within. 14. Hit the “clear data” button. This time, narrow the pH down within the range determined in the previous trial(s). Change the pH in increments of 0.1 until you find the one that works best. Record that pH level on #4 of your data sheet, and answer question #5. 15. Clear your data. Enter the optimum pH value determined in the previous trial. Keeping in mind the information given about the normal body temperature of a calf, input a temperature and hit “graph data.” Experiment with various temperatures until you find the optimum temperature. Record that on #6 on your data sheet. Then, answer #7 & 8. 16. Hit the continue button until you come to the “observations” page for Sweet potato phosphatase. Read the information in the paragraphs. Make a prediction about what the optimum pH and temperature will be for this enzyme, and record that on your data sheet for #9. 17. Using the same procedures followed for the calf intestinal enzyme, determine the optimum pH and temperature levels for this enzyme. Remember you must clear your values in between trials, and you must select the enzyme from the list on the top left. Record your results on #10 on your data sheet, and answer #11-13. 18. Hit the “continue” button until you come to the “observations” screen for the Thermus acquaticus. Read the information on that page, then advance to the next “observations” page and read that information. Based on that information, make a prediction about the optimum pH and temperature for that enzyme, and record it on #14 on your data sheet. 19. Hit the “continue” button to advance to the trial page. Select the proper enzyme from the top left button, and use the same procedure followed to determine the optimum pH and temperature for this enzyme. Record your results for #15, and answer # 16-20.
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