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)
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!! poison
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)
In a recent experiment, I discovered that if allowed, boys will eat ice cream until they become sick!

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
You will also design an experiment next week and write an informal lab report on the experiment next week.
This Informal LAB REPORT due in 3 weeks but please get started now.
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

15. Writing an Informal Lab Report
To help you write an informal lab report, you will do the “Paper Assignment”, see the link on the main lab web page.
In the Paper Assignment, you will read the scientific paper found in the appendix of your lab manual and answer the questions from the Paper Assignment link.
The Paper Assignment is due in 1 week.