This chapter presents a case study on The Prokaryotic Resistance of Penicillin using the discovery engineering process. In this lesson, students explore the history and discovery of penicillin which revolutionized the treatment of bacterial infections. However, antibiotic resistance has become a serious issue due to the misuse or abuse of antibiotics. Students will model antibiotic resistance through a hands-on activity and use sample data to determine the efficacy and safety of using bacteria for a medical treatment with animal trials. Finally, students use case information to design a new use for a specific species of bacteria or fungi. This lesson may be taught during a unit on bacteria or fungi characteristics, infectious disease, antibiotic resistance, or genetics. A list of materials, teacher background information, teacher notes, references, resources, assessments, and standards are provided. This book selection also includes the Table of Contents, About the Authors, Acknowledgments, Introduction, and Index.