The Poisson distribution played a key role in experiments that had a historic role in the development of molecular biology. In particular, the interpretation and design of experiments elucidating the actions of bacteriophages and their host bacteria during the infection process were based on the parameters of the Poisson distribution. I briefly review three of the most important of these experiments and offer suggestions on the use of the Poisson distribution in statistical calculations in biology laboratory exercises reflecting the use of the Poisson distribution in current biological investigations.

Students often struggle to understand the complex molecular systems and processes presented in introductory biology courses. These include the Calvin cycle, the Krebs cycle, transcription and translation, and DNA replication, among others. Traditionally, these systems and processes are taught using textbook readings and PowerPoint slides as lecture aids; video animations have also become popular in recent years. Students tend to be passive observers in many of these methods of instruction, relying heavily on “memorization” learning techniques. To address this, I developed an active-learning intervention called “molecular sculpting” in which students construct two-dimensional or three-dimensional versions of an assigned molecular system or process, complete with representations of proteins, chromosomes, electrons, protons, and other molecules (depending on the system). The value of this learning activity was measured in five class sessions in an introductory biology course during the 2014–2015 academic year. Pre- and post-class written assignments showed that students were often able to describe course concepts more completely after sessions in which sculpting was used, compared with sessions without sculpting. Molecular sculpting is a unique, hands-on activity that appears to have significant learning gains associated with it; it can be adapted for use in a variety of K–14 biology courses.

Active learning exercises can help students understand and remember complex, three-dimensional processes. By modeling molecular processes with their bodies, students gain an appreciation for the three-dimensional nature of these processes and the physical sequence of events that constitute them. The exercises presented here focus on DNA replication and the translation of mRNA into amino acid sequences, multistep processes that require specific series of events. The exercises help students appreciate the spatial and temporal frameworks of these essential cellular functions. They can be incorporated into classes when these concepts are introduced or used as review exercises for exams.

The importance of a robust undergraduate research experience has been demonstrated time and again. However, too few undergraduates engage in genuine research and leverage this opportunity. Here, I present a laboratory course in cell and molecular biology that is designed to mimic a true research project. Students work through a 10-step experimental design culminating in the construction, expression, and visualization of microtubules fused to green fluorescent protein in baker's yeast. The steps of this project include the isolation of the tubulin gene from yeast genomic DNA, the cloning of that gene into an expression vector, the amplification of this plasmid in E. coli, and the expression of fluorescent tubulin in yeast. Controls and validation steps are embedded throughout the project, as they would be in a genuine research project. This laboratory course more closely resembles a one-semester undergraduate research experience than a typical lab course. However, because this course reaches a much larger number of students compared with undergraduate research opportunities, it provides students with a valuable research experience that remains confined to the scheduled time block of a typical lab course. In this way, many of the benefits of research are experienced by a large number of undergraduates.

This paper presents an activity that engages students in model-based reasoning, requiring them to predict the behavior of the trp and lac operons under different environmental conditions. Students are presented six scenarios for the trp operon and five for the lac operon. In most of the scenarios, specific mutations have occurred in genetic elements of the system that alter the behavior from the norm. Students are also challenged to relate their understanding of operon behavior to the “Big Ideas” of homeostasis, evolution, information, interactions, and emergent properties. By using operons to teach students to reason with models of complex systems and understand broad themes, we equip them with powerful skills and ideas that form a solid foundation for their future learning in biology.