This simulated exercise is intended to familiarize students with the flow of steps involved in signal transduction. Students divide into two teams of 15 or more students, and each student in the team is assigned to be a component of a signal transduction pathway within the classroom "cell." The two teams compete for the fastest signal transduction time, starting with a signal molecule contacting a cell receptor and ending with the transcription of a gene. Students then make modifications to make the steps more efficient, thereby decreasing the signal transduction time. This activity can easily be designed for any signal transduction pathway for any cell.