Agenda

1. Agenda • Collect Pre-lab #6 • Lab Quiz #5 • Paper Assignment due • Preview your Informal Lab Report for next week • No Microworlds available from this lab. • Yet, you may use pond water, the microworld slides, and maybe others?

2. Enzymes

3. Enzyme Reactions ENZYME SUBSTRATE PRODUCT

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 (Catechol oxidase) Catechol + O2 Benzoquinone + H2O Colorless Brown Catecholase (from Potato Extract) Lab manual left off the water!

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

10. Exercise 1 – Effect of enzyme concentration on Reaction Rate • We will use the Color chart method • A Color change = what? • Look at the set-up of the experiment. Answer questions about the experimental design. • Set up the experiment as directed in the manual. The reaction begins once catecholase and catechol are together. • Watch reactions for 5 minutes, inverting to mix every minute. • Record the color of each tube after each minute. • Understand that potato extract is dark to begin w/ because it has both catechol & catecholase!

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!! • Be quick & work together!

12. Part 2: Designing an Experiment • Design an experiment to test one of the following using catecholase: • pH buffers (on counter, do not use pH 11!) • Temperatures (water baths in the back) • Different substrates (sugars and starch) • Salt concentration (on 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. Designing an Experiment And Writing a Lab Report • LAB REPORT rough draft due next week • Look at the format and example of a lab report in Appendix A of lab manual • Look at How to Write a Scientific Paper in Appendix A of lab manual • See the Lab Report Peer Review sheet on my web site for how it will be graded

15. Writing a Lab Report • TYPED • 12 point font, double spaced • TITLE • Should tell what will be in the lab report • Good format is “The effect of the independent variable on the dependent variable”

16. 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

17. 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

18. 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 and does NOT explain why you observed the results. • 1 paragraph of text plus a table, graph, or etc.

19. Writing a Lab Report • DISCUSSION (& Conclusions) • Summarize your problem & hypothesis (review it). • Summarize your data by discussing specific data in sentences. (Summarize, no raw data.) • Discuss what your results mean. • Discuss the importance of your results and how it ties in with what you wrote in the introduction. • Discuss how your results answer (or do not answer) your original question • Is your hypothesis supported by this data or not?

20. Writing a Lab Report • DISCUSSION (& Conclusions) • IF YOUR HYPOTHESIS WAS SUPPORTED: • Evaluate possible explanations for the results based on the information in your introduction. • Answer your question. • Explain things that could be improved in your experiment and what were possible errors. • Discuss future studies that would add to your results.

21. 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 and how you could correct any errors. • Discuss future studies that would add to your results.

22. Writing a Lab Report References (lab manual calls it Literature Cited) • See info in Appendix A • At least THREE references: • At least ONE peer-reviewed journal article from a scientific publication • Not including your lab manual (although you can reference this for one of the two other references) • Anything from wikipedia or the web do not count & MUST be confirmed with an additional source!

23. What to turn in • ROUGH DRAFT due next week • Bring Three copies of your rough draft • Make three copies of the Peer Review Grading Sheet and staple a copy to each copy of the rough draft. • 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