Agenda

1. Agenda Collect Pre-lab #5 Lab Quiz #4

2. LAB 5: Enzymes

3. Enzyme Reactions

4. Enzyme Reaction Rate Effect of enzyme concentration on reaction rate

5. Enzyme Reaction Rate Effect of substrate concentration on reaction rate

6. Enzyme Reaction Rate Effect of pH on reaction rate

7. Enzyme Reaction Rate Effect of temperature on reaction rate

8. Catecholase

9. Catecholase Present in plants (potatoes) Reaction seen when potatoes or apples turn brown

10. Exercise 1 � Effect of enzyme concentration on Reaction Rate Color chart method Color change = what? Look at the set-up of the experiment. Answer questions about experimental design. Set up the experiment using the procedures on the back and the Table on the front. Watch reactions for 5 minutes, inverting to mix every minute. Record the color of each tube after each minute (different from procedures)

11. Exercise 1 � Effect of enzyme concentration on Reaction Rate THINGS TO NOTE: Catechol is toxic (don�t drink it; wash hands) Catechol waste goes in the bucket Keep potato extract on ice Be accurate!!

12. Part 2: Designing an Experiment Design an experiment to test one of the following using catecholase: pH buffers (counter) Temperatures (Water baths) Different substrates (Sugars and starch) Salt concentration (counter)

13. Part 2: Designing an Experiment Things to think about: What will your control group be? # of trials (replication)? Volumes of different solutions? Timing of reactions / when you measure color?

14. Part 3: Designing an Experiment LAB REPORT #1 due next week Look at the format at the end of the lab manual

15. How to Write a Scientific Paper See Appendix B in lab manual Look at peer review sheet 15

16. Writing a Lab Report TYPED 12 point font May be single or double spaced

17. Writing a Lab Report TITLE Should tell what will be in the lab report Good format is �The effect of the independent variable on the dependent variable�

18. Writing a Lab Report INTRODUCTION Background information about your experiment General background someone would need to understand the topic Specific background someone would need to understand your experiment Important vocabulary Very brief summary of your experiment Question you�re addressing State hypothesis Explain why the hypothesis is worth investigating Make predictions about results 3-5 paragraphs

19. Writing a Lab Report MATERIALS and METHODS (Procedure) Detailed description of what you did so that someone else can replicate your experiment Discuss your experimental design State the independent and dependent variable Identify control, constants, replication Use the passive past tense (�the solution was heated� not �we heated the solution�) Write using paragraphs Be specific (measurements, units, etc) About 2-3 paragraphs

20. Writing a Lab Report RESULTS Even if it doesn�t support your hypothesis, it�s still a result! Present ALL data in an organized, meaningful form (quantitative, qualitative) Data in table(s), Graph(s), or Figure(s) (pictures) A paragraph that presents DATA, does NOT explain why you observed those results. 1 paragraph plus table, graph, etc

21. Writing a Lab Report DISCUSSION (Conclusions) Summarize your problem and hypothesis (review) Summarize your data by discussing specific data in sentences Discuss how your results answer (or do not answer) your original question How do your results fit with what you know? Importance of results Is your hypothesis supported by this data or not? Did you confirm your predictions?

22. Writing a Lab Report DISCUSSION (Conclusions) IF YOUR HYPOTHESIS WAS SUPPORTED: Evaluate possible explanations for the results based on background information. Answer the original question. Explain things that could be improved in your experiment Discuss additional experiments that would add to your results.

23. Writing a Lab Report DISCUSSION (Conclusions) IF YOUR HYPOTHESIS WAS NOT SUPPORTED: Evaluate possible explanations for the results based on any experimental errors OR personal misconceptions / lack of background information. If your experiment didn�t work due to errors, you CAN NOT answer original question. Explain things that could be improved in your experimental design or how you could correct errors Discuss additional experiments that would add to your results.

24. Writing a Lab Report CITATIONS Refer to info in Appendix B At least THREE sources: At least ONE peer-reviewed journal (check with library) Not including your lab manual (although you can ref this) Anything from wikipedia or the web MUST be confirmed with another source

25. What to turn in ROUGH DRAFT due next week Bring Three copies of your rough draft Make three copies of the peer review grading rubric and staple one copy of rough draft to one copy of grading rubric. Deduction if this is not done as both are needed by your peer reviewer. NEXT WEEK: Rough drafts will be distributed randomly for you to peer edit

26. Using the Spec Read your samples Prepare samples containing water, catechol and potato extract Re-blank spec Read absorbance for each sample

27. Part 2: Catecholase Measuring color change with spectrophotometer � measures the amount of light that penetrates at different wavelengths

28. Part 2: Product Formation and Absorbance

29. Using the Spec Zero the spec Mix 1mL potato extract + 5mL dH2O in tube Invert tube to mix and wipe clean so the spec can read it appropriately. Follow the directions for using the spec (each may differ). You will need to zero it. When the spec is ready, insert the tube (mark it so you insert it the same way every time) Make sure the spec readings make sense; if something is off the readings are garbage