Players in the Pathway

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Categories: GSI Online LibraryTeaching Effectiveness Award Essays

by Susan Schwab, Molecular and Cell Biology

Teaching Effectiveness Award Essay, 2002

One challenge I faced teaching immunology section was how to review complex biochemical pathways. The fascinating and exciting part is why the pathway is important, how it was discovered, and what remains unknown. But knowing the alphabet soup of components is necessary for following the discussion and, more immediate for many students, passing the exam. The professor asked me to give a section about the complement pathway (for killing bacteria) when he ran short on time; to my horror, I found that the textbook had 20 pages of “C4bC2b cleaves C3, and then…” So I divided the section into three parts based on a play, each of was designed to reach different students and add another layer to the discussion.

First, I made up a handout (“Synopsis”) going over what I thought were three key questions: What is the end result of complement activation? What triggers the pathway to start? What feedback loops cause its amplification? Addressing these issues gave a reason to learn about complement and organized the different molecules. Distributing a detailed handout helped the students participate and think about the pathway as a whole because they didn’t have to scribble frantically down all the names. But the fact remained that we still had to follow the steps, ideally in a way that would aid memorization.

The actual play was designed to accomplish this. I wrote up the pathway and handed out stage directions, such as:

Act IV: C3

Enter C3a and C3b, holding hands.

C4bC2b (C3 convertase): cleave C3a from C3b.

C3a: Exit, go be inflammatory.

C3b: Attach to pathogen, providing a handle for macrophages to phagocytose (eat) it.

I made up paper hats with the names of the components on them, put them on the students, and directed the actors. The class loved it — to my amusement, both sections spontaneously gave themselves a standing ovation. Students who sat in the back were drafted into participating. Students asked more questions even than in a review session: “Wait, what am I cleaving? What are they going to do?” They had something concrete to ask about, and neither they nor I could look any sillier! Having participated once, I hope that they felt more comfortable asking questions in later sections; I regret that this play was at the end of the semester.

Last was “Audience Discussion.” I researched human diseases involving complement and wrote a couple questions relating what we had learned to medical problems; this cemented the importance of the pathway, emphasized the role of the key components, and most important spurred discussion of future experimental directions. One strategy I always tried to use when asking questions was to encourage discussion but then to repeat the key points crediting students who made them by name, so that those who spoke could feel the excitement of participating but everyone could hear and distill the important information.

To get feedback, I handed out an evaluation form twice during the semester and put a suggestion box out at every lecture. The play was at the end of the term, so feedback was directly from students talking to me or the professor — many students went out of their way to compliment the complement play. I suggested this technique to a GSI the next semester, who used it for T cell signaling and also reported a hit.