Transcript Case File: 1007 “Who Killed Yanni the Yeast?” The Victim The Victim Yanni “The Yeast” Yarkow Earned his nickname by building 5000 factories.

Case File: 1007
“Who Killed Yanni the Yeast?”
The Victim
The Victim
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 Crime Scene
The Crime Scene
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
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
Yeast as a model system
Yeast + water + sugar + O2
CO2 + alcohol
If yeast are healthy, they will produce a great deal of CO2
The Ziploc baggie will fill up with C02
Q. What is CO2?
What if the yeast are not healthy because something toxic has
been added?
Q. Will the baggie fill up as much?
Making a dose response curve
Dose response curves are used to determine how much of a compound is toxic
Height of Ziploc Bag
(centimeters)
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.
1.
Which compound is the most toxic?
Hint: If it is toxic, would the yeast produce
more or less C02?
2.
Which compound is the least toxic?
3.
Dose of Compound
(Teaspoon)
Instructions
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
Control
High
(1 teaspoon)
Medium
(1/2 teaspoon)
Add 2 tablespoons of warm water
Low
(1/4 teaspoon)
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?
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Case File: 1007
“The Murder of Yanni the Yeast”
The Suspects
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
72097
Corvallis, OR
Yasmina Yarkow
Found at the Crime Scene:
1 earring, belonging to Yasmina Yarkow
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.
72098
Corvallis, OR
Yardley Tohilo
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.
Scherz Cleaning Co.
72099
Corvallis, OR
Yvonne Scherz
The only cleaning company authorized to use
a top-secret cleaning compound!
“Floors so clean they sparkle!”
That’s the Yvonne Scherz promise!
The Poison
Powdered milk
Cleaning compound
Salt
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
Results from the Police Laboratory
The unknown substance found to have poisoned Yanni
Yarkow was identified as the top secret cleaning
compound.
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.
72099
Corvallis, OR
Yvonne Scherz