1. Case File: 1007 “Who Killed Yanni the Yeast?”

2. The Victim

3. Yanni “The Yeast” Yarkow Earned his nickname by building 5000 factories that produce bread yeast throughout the United States of America Married to Yasmina Yarkow Location: Found in the library, holding a glass. Cause of Death: Suspected poison The Victim

4. The Crime Scene

5. At the scene, three unknown compounds were found next to the victim - Compound A - Compound B - Compound C It is your job to identify these compounds

6. How to identify the unknown compounds We will use yeast as a model system to test the compounds Each group will be assigned a compound (A, B or C) to test – Perform a dose response with your compound and compare to a control (no compound) – Compare your dose response to known chemicals

7. If yeast are healthy, they will produce a great deal of CO 2 The Ziploc baggie will fill up with C0 2 Q. What is CO 2 ? Yeast + water + sugar + O 2 CO 2 + alcohol What if the yeast are not healthy because something toxic has been added? Q. Will the baggie fill up as much? Yeast as a model system

8. Height of Ziploc Bag (centimeters) Dose of Compound (Teaspoon) Which compound is the most toxic? Hint: If it is toxic, would the yeast produce more or less C0 2 ? Which compound is the least toxic? 1. 2. 3. Making a dose response curve Dose response curves are used to determine how much of a compound is toxic Example: When you take Tylenol, you only take two at a time. If you take more, they can be toxic and lead to an overdose, making you very sick.

9. Instructions Control High (1 teaspoon) Medium (1/2 teaspoon) Low (1/4 teaspoon) Label 4 plastic bags as shown – put your initials on each bag! To ALL bags, add: -1 ½ teaspoons yeast -1 ½ teaspoons sugar Add either Compound A, B or C to the three bags labeled “High”, “Medium”, or “Low” following the directions Add 2 tablespoons of warm water

10. Instructions Place your bags on the heating tables Things to think about What happens if the water was too hot? What if the water was too cold? Why do we need controls? ++

11. Case File: 1007 “The Murder of Yanni the Yeast”

12. The Suspects

13. 72097 Corvallis, OR Yasmina Yarkow Occupation: Jewelry designer Relationship to the victim: Wife Potential motive: Yasmina wanted to open her own jewelry design business, but her husband refused to lend her the money she would need to buy materials Found at the Crime Scene: 1 earring, belonging to Yasmina Yarkow

14. 72098 Corvallis, OR Yardley Tohilo Occupation: Owns his own bakery, Tohilo Breads Relationship to the victim: Has baked for the Yakow family for 20 years, using yeast provided by Yanni. His is the only bakery allowed to use Yakow Yeast. He is famous for his Tohilo loaf; a loaf consisting of only yeast, flour, salt and powdered milk Potential motive: A new bakery has opened down the street, and Yanni has agreed to sell them his yeast.

15. 72099 Corvallis, OR Yvonne Scherz Occupation: Owner; Scherz Cleaning Co. Relationship to the victim: Distant cousin of Yasmina Yarkow Potential motive: A year ago, was hired by Yanni’s company to clean the floors of his factory. Yanni was dissatisfied when his floors did not sparkle as promise, and sued. She is in danger of losing her cleaning company. “Floors so clean they sparkle!” That’s the Yvonne Scherz promise! Scherz Cleaning Co. The only cleaning company authorized to use a top-secret cleaning compound!

16. The Poison

17. Powdered milk

18. Cleaning compound

19. Salt

20. Which is the most toxic? The most toxic compound is assumed to be the one that killed Yanni the Yeast – To confirm this, a police laboratory tested the compound that Yanni ingested right before he died

21. Results from the Police Laboratory The unknown substance found to have poisoned Yanni Yarkow was identified as the top secret cleaning compound.

22. 72099 Corvallis, OR Yvonne Scherz Yanni was suing her company. She couldn’t pay the legal bills, and was about to lose her business. She thought that if Yanni was gone, the civil suit against her would go away, and she could keep her business.