BIOS 2011 Lab 1 Enzymes

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Unformatted text preview: e on your data worksheet for Experiment 3 below. 3. Label 4 Small test tubes for starch/buffer mixes as follows: pH5, pH6, pH8, pH9. Each tube will have the same amount of starch, but a different pH Buffer. To each small tube add 2mL of starch. Then add 2mL of the correct pH buffer. Vortex 30 seconds. 4. Perform 4 different pH buffered reactions with starch ­iodine testing. Again, only perform one reaction at a time. Use essentially the same procedure as in steps 3 ­7 of Experiment 2. The only difference is that you will use 1000µL of the selected a ­Amylase stock for each reaction, and the pH will be different in each reaction. * Note: we advise you to start with the pH values closest to 7, then perform the reactions with the more extreme pH of 5 and 9. Use a longer interval of 20 ­30 seconds for pH of 5 and 9. 5. Record each endpoint time on your worksheet, and calculate rates as in Experiment 2. Worksheet for your pH experiment results: You can record your observations here, but be sure to generate a new table for your lab write ­up as described in Appendix I. pH Starch added (mg) Time to Complete Reaction (sec) Reaction Rate (mg/sec) 5 6 7 8 9 Notes: 10 Exercise 1 Enzymes APPENDIX I: GUIDELINES FOR THE LAB WRITEUP This should be prepared using Microsoft Office, Apple iWork or the freeware OpenOffice or NeoOffice applications or equivalent word processing and graphing programs. For submitting work to be graded, export as a PDF or DOC file and upload to your TF’s online dropbox. OpenOffice is available from for Windows, Linux and Mac OS X. NeoOffice is available for Mac OS X only at: . Keep your write ­up short and avoid unnecessary repetition. You must follow the guidelines in Appendix B: How to present results, which is available on the “Laboratory” page of the course website. Please make sure your name and your TF’s name appear on the first page! You may use data from other groups if your experiment fails to give clear results. If you use another group’s data, you should credit them by name as the source of the data. If you collaborate with another pair of students for the third part of the experiment, you should note their names as well. Succinic dehydrogenase: 1) Make a table of the contents of each tube and the colors at the beginning and the end of your experiment. Pay attention to: Table #, Title, Column Headings, & organization. The title should be specific and describe the experiment, naming the active components. As a caption to the table, provide a short paragraph explaining your results. Describe whether there was a color change in each tube and what that shows about the enzyme’s activity in that tube (no activity, very inhibited, slightly inhibited, uninhibited, etc.). Explain why each of the first four tubes are controls and how they help you to understand the level of inhibition in Tubes 5 & 6. What is your hypothesis about the kind of the inhibitor Malonic acid would be for Succinic Dehydrogenase? A hypothesis is a question in the form of a statement that your data may either support or reject. How does your data from Tubes 5 & 6 support or reject your hypothesis? a Amylase: 2) Graph the rate results of your a ­Amylase concentration experiment on an X ­Y scatter plot. Calculate Rate from your raw data. Rate=10mg/Time to endpoint. You should NOT present your raw worksheet timing data unless requested by your TF. Include: 11 Exercise 1 Enzymes a) Figure #: Title: This should specifically state what kind of chemical reaction by what enzyme on what substrate. You should have only one title per graph, either above or below the plot. b) Labeled axes and scale. Plot the variable that you manipulated on...
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This note was uploaded on 02/09/2012 for the course BIOLOGY 102 taught by Professor Anderson during the Spring '11 term at Harvard.

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