Using a microbial physiologic and genetic approach to investigate how bacteria sense physical stimuli

Use of a Role-Playing Activity To Increase Student Understanding of Bacterial Gene Regulation

Undergraduate students often struggle to understand the basics of bacterial gene regulation, a key concept in microbiology. They find it hard to visualize the architecture of a bacterial operon or how the gene, RNA, and protein components interact with each other to regulate the operon. To better visualize the molecular interactions, students engaged in a role-playing exercise on bacterial gene regulation in the classroom. Before beginning the activity, they received a shortened, traditional lecture on the architecture and function of the lac operon under "on" and "off" conditions. Students chose one or more placards detailing a molecular role (such as promoter, repressor, RNA polymerase, gene X, gene Y, etc.). Upon receiving instructor prompts, they assembled in linear order to mimic correct genomic locations of genes and regulatory elements on the operon. When given a prompt for "operon on" or "operon off" condition, students identified all the necessary components (roles) for that condition, assembled in the correct order, and then moved through the assembled operon to mimic what happens inside the cell under that condition. Students were tested before and after the activity using a set of eight multiple-choice questions. Students showed significant gains in their ability to answer these questions correctly immediately after the activity. More importantly, the improved understanding was also reflected in a high median score on summative assessments given a few weeks after the completion of the activity. This activity can also be readily adapted to online or a hybrid mode of teaching to benefit larger student populations.