Skip to Content

The Mystery of the Seven Deaths

A Case Study in Cellular Respiration


Michaela Gazdik Stofer
Department of Biology
Utah Valley University


In this interrupted case study, students learn about the function of cellular respiration and the electron transport chain and what happens when that function is impaired. The case is loosely based on the real-life 1982 Chicago Tylenol murders where seven people died when Tylenol capsules were laced with cyanide. Students play the role of medical examiner as they analyze the autopsy results to determine the cause of the mysterious deaths of these seven victims. The case was originally used in a general biology course taken by both science majors and non-majors.


  • Explain the overall purpose of cellular respiration.
  • Describe the intermediate metabolites of cellular respiration.
  • Explain the function and importance of the electron transport chain.
  • Describe the role of oxygen in cellular respiration.


Cellular respiration; hypoxia; blood oxygen; metabolic pathway; metabolite; pyruvate, acetyl coenzyme A; NADH; cytochrome c oxidase; electron transport chain; adenosine triphosphate; ATP; product tampering; cyanide poisoning; Tylenol

Topical Areas


Educational Level

Undergraduate lower division



Type / Methods

Interrupted, Role-Play



Subject Headings

Biology (General)  |   Molecular Biology  |   Cell Biology  |   Physiology  |  

Date Posted


Teaching Notes

Case teaching notes are password-protected and access to them is limited to paid subscribed instructors. To become a paid subscriber, begin the process by registering.

Teaching notes are intended to help teachers select and adopt a case. They typically include a summary of the case, teaching objectives, information about the intended audience, details about how the case may be taught, and a list of references and resources.

Answer Key

Answer keys for the cases in our collection are password-protected and access to them is limited to paid subscribed instructors. To become a paid subscriber, begin the process by registering.


Kara Marshall

Science Department
Westmoor High School
Daly City, California
I just wanted to say what a great idea for teaching cellular respiration. Thank you for putting it on the Web.

Kim Pause Tucker
College of Coastal Georgia
Brunswick, GA
My Bio I students really enjoyed working through this lab activity. We ended by watching a YouTube video about the Tylenol murders, which they were all really interested in. I think that this really helped them to understand respiration and the electron transport chain better. Thanks! :)

Adrian Correa
IDEA College Preparatory
San Benito, TX
This is one of the best case studies I've used so far. My AP Biology students were engaged throughout the entire activity and really enjoyed taking on the role of medical examiner. I was especially inspired listening to their small group discussions. This case study is definitely a keeper.

Peter Cavnar
University of West Florida
Pensacola, FL
I love this case study and my students really enjoy it. Thank you for making this available. One minor correction is that according to the total in the description there were eight victims instead of seven. One of my students caught that so I can't even take credit for it.

Caroline Sorensen
Science Department
Greenbush Middle River High School
Greenbush, Minnesota
What a wonderful activity.

Kim Gillard
Science Department
Lacombe Composite High School
Lacombe, Alberta
I adapted this case to be done as a Google Form - an online questionnaire (posted only to students in my class), revealed one page at a time. It was effective in getting the whole group involved, especially as many are hesitant to speak up in a group discussion, but had thoughts they were eager to type on their phones. They were full of questions by the end of the class, about the real-life events. Thanks for an engaging lesson!