Biomolecules Hidden in Plain Sight

When I consider adopting a new textbook for a course, I have one main concern: my audience. I teach a wide variety of students; the chemistry major who began doing research his freshman year on his path toward graduate school, the psychology major who is concerned about his GPA and preparation for the MCAT, the art major who finds chemistry interesting enough to pursue a minor, and the biology major who is just hoping to pass to fulfill requirements for graduation. Balancing the needs and interests of such a varied audience is always a challenge, but careful choices in the organization and framing of the course can help.

Traditional textbooks have an organization based on functional groups, but my experience is that true mastery of a topic comes with an understanding of underlying concepts, enabling application to new situations. There is only so much a person can memorize, but building a mental model by making contextual connections using a strong framework leads to greater success and retention. Needless to say, Joel’s textbook and its mechanistic organization jumped out as an exciting change of pace with its emphasis on understanding the electron movement. But a quick glance through the table of contents begged the question, where is the chapter on biomolecules, the traditional bridge to the subsequent biochemistry course?

I team-teach organic chemistry with a biochemist-by-trade and we are continuously frustrated that biomolecules are somehow separate from their functional groups in traditional books. They are relatively large molecules, but their reactivity is still based on functional groups and many reactions in the biomolecules chapter feel repetitive. Additionally, they are typically placed at the very end of the second semester, when students can’t seem to fit any more information into their heads and the apparent complexity of all those chiral centers seem overwhelming. At the same time, it is scary to imagine introducing biomolecules in the first week of class! If students are still learning how to interpret line drawings, how could they possibly be ready for complex biomolecules?

For the first time this year, my solution has been to consider biomolecules as a natural application of the fundamental principles of organic chemistry and to continue to return to them throughout the course, as the Karty textbook does. More useful than special interest boxes, biomolecules are made relevant through an individual section in several chapters. I’m always drawing random molecules to fit the purpose of a homework problem or exam question, why not simply use a nucleotide to demonstrate the importance of keto-enol tautomerization, a peptide to calculate formal charges, a carbohydrate to demonstrate stereochemistry and stability of chair conformations, and an amino acid to discuss pKa values? These examples, and many more, provide opportunities to ask interesting, concept-driven questions with a practical application. And although students are initially overwhelmed by the size of the biomolecules, they quickly grow accustomed to the idea that functional group reactivity is the key consideration regardless of the complexity of the molecule; a critical realization. My sincere hope is that interspersed incorporation of biomolecules will lead students to a better understanding of their chemistry, rather than trying to cram everything in the last few weeks of the course.

When I contemplate the varied interests of the students in the course, I have found an unexpected benefit to incorporating biomolecules early and returning to them often. The motivated chemistry major begins to ask higher-level questions about applications of topics in the course. The student with an intense focus on metrics for medical school becomes confident that this work will help him prepare for subsequent coursework and the added biochemistry component of the MCAT2015. The student taking the course simply because he is interested in chemistry sees a broader context. And that biology major who is just there to get a passing grade becomes invested in topics that apply to his other courses. Finally, biomolecules provide a theme that students can continue to relate concepts to, thereby building a framework of understanding and leading to a deeper knowledge of organic chemistry.

-Laura Wysocki, Wabash College

Click here to learn more about Prof. Wysocki.

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