Student Worksheet Mutagenesis Lab

Procedure 1. Clean your hands and work area. • Clean your hands with hand sanitizer • Put all the food away

2. Acquire a Petri dish from your instructor and label it using a waterproof marker. • Write your name in small letters around the outside edge of the bottom of the dish. • Draw lines on the bottom of the dish to divide it into 3 parts.

• Label one area “control”. What is a control and why do you need it? What is your control? • Label each area on the bottom of the dish. • Write in small letters around the edge.

3. Pick a mutagen. • Discuss with your partner what mutagen you want to test. You can test the same mutagen as last time or pick a different one from the collection provided by your instructor. Note that if you want to test your own mutagen, you should first talk to your instructor! • Label one of the remaining two thirds of the Petri dish with the name of the mutagen you chose.

4. Modify the protocol For the last third of the Petri dish you will modify the protocol in a way that will make your mutagen stronger or weaker!

Option A: Yeast Protection • Discuss with your partner how you can modify the described about mutagenesis with your substance of choice in order to make it less mutagenic. You can: -> add less mutagen (less than 2 drops of liquid or a scoop of powder/solid) -> incubate for less than ten minutes -> add another substance in addition to the first one -> protect from sunlight -> use your imagination! • Write down the modifications you’ll make to the protocol. Option B: Stronger mutagenesis • Discuss with your partner how you can modify the described about mutagenesis with your substance of choice in order to make it more mutagenic. You can: -> add more mutagen (more than 2 drops of liquid or a scoop of powder/solid) -> incubate longer than ten minutes -> add another mutagen in addition to the first one -> expose to sunlight -> use your imagination! • Write down the modifications you’ll make to the protocol.

5. Acquire yeast from your instructor. • Label the tubes and the pipettes -> A: control, B: your mutagen, and C: modified mutagen. • Swirl the container of yeast. • Add water (2 drops) to the control yeast (tube A). • Add your mutagen of choice to the second tube with yeast (tube B). If your mutagen is liquid (shampoo, hot sauce, etc.), add 2 drops. If your mutagen is very viscous, powder or solid (toothpaste, splenda, etc.), pick a small amount with a toothpick and add to the yeast container. • If you are modifying the amount of mutagen added to the third container (tube C), add the altered amount (more, less, in combination with another mutagen, etc.). Otherwise, add the same amount of mutagen as in tube B. • Incubate the yeast for 10 min. Note: if you are altering the incubation time for tube C (incubate for more or less than 10 min), incubate that tube accordingly! • Acquire a questionnaire from your instructor and fill it in while waiting. Return your completed worksheet to your instructor when you finish! • After the incubation, transfer the yeast solution with a sterile pipet on the media on the corresponding thirds of the plate. • Gently spread the liquid with a toothpick. • Let it dry for 5 min. • Return the plate to your instructor

6. Return the plate to your instructor. He/she will place it at 30C for the next 3-4 days and allow the yeast to grow. Guidelines for your Presentations:

You will have 5 minutes to present your work from the Cancer and Mutagenesis lessons to the class. There will be time at the end for your classmates and instructors to ask questions. Presentations will be Monday, March 24. There will likely be other teachers and / or administrators present.

Everyone in your group should participate during your presentation!

Please address each of the 6 sections described below in your presentation:

1. Introduction What are mutations and why are they interesting? Why do you want to test if a substance is mutagenic?

2. Hypothesis What substance did you choose and did you expect your substance to make mutations? Did you expect to see colonies on the plate?

3. Procedure How did you do your test?

4. Results How many colonies did you count on the control part and on the test substance part of the plate? Was your substance a mutagen (chi square).

5. Modifications What did you change and why? What were the results?

6. Conclusions Were the substances you tested mutagenic? If you could do another experiment, what would it be and why?