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Why is Patrick Paralyzed?

Maureen Knabb
Department of Biology
West Chester University of Pennsylvania


This “clicker case” introduces students to a rare genetic disease in which an enzyme is deficient in a critical metabolic pathway—the first step in aerobic respiration. Based on a real-life situation, the case challenges students to make connections between energy production, enzymes, and metabolic diseases. The case was developed for one-semester, majors’ introductory biology course taken primarily by freshmen and sophomores to fulfill a general education requirement, but could be used in any introductory biology course.  It consists of a PowerPoint presentation (~1MB) shown in class that is punctuated by multiple-choice questions the students answer using personal response systems (aka “clickers”). The case could be adapted for use without these technologies.


  • Understand why energy is necessary for sustaining life (a unifying theme in biology).
  • Appreciate the importance of enzymes for catalyzing chemical reactions.
  • Recognize that energy conversions are dependent on metabolic pathways.
  • Understand the role of enzyme inhibition in metabolic pathways and predict the effects of enzyme deficiency due to genetic disease.
  • Apply knowledge of converging metabolic pathways and enzyme inhibition to understand the treatment options for a metabolic disease.


Metabolism; metabolic pathway; adenosine triphosphate; ATP; energy; enzyme; glycolysis; lactate fermentation; competitive inhibition; aerobic respiration; metabolic disease; pyruvate dehydrogenase complex deficiency; PDCD; paralysis

Educational Level

High school, Undergraduate lower division


PDF, PowerPoint

Type Methods

Clicker, Interrupted



Subject Headings

Biology (General) Molecular Biology Biochemistry Medicine (General)

Date Posted


Teaching Notes



Answer Key



Vera Verga
Edison State College
Naples, FL
Thank you for this very informative case study. It was a great activity to explain the activity of enzymes and cellular respiration. Many of my students are inspired when they can relate the activity to themselves or another human.

Laura Wodlinger
Westmount Collegiate Institute
Toronto, ON
Thank you for this amazing case study. My students are very inspired to learn and solve the problem. I was wondering why Patrick did not begin to show symptoms until he was 16. If this was a genetic disorder why were the onset of symptoms so delayed? Thank you.