Putting Some (but not too much) Biochemistry in Organic Chemistry

One of the key features of our new organic chemistry curriculum at Middlebury College is that the premed students (and anyone else who is so inclined) can take biochemistry after just one semester of organic chemistry (vs. a whole year). I have previously written about these details and how well Joel’s mechanistically organized textbook helped us do that. One specific feature of the course that I and the students really like is that we spend the last two weeks or so of the term going through “organic chemistry in action” topics such as glycolysis, lipids, proteins, DNA & RNA, and carbohydrates. Typically we spend a day on each topic. It is easy to see why this is popular with students and the instructors of our subsequent biochemistry course, but how is it for me as an instructor?

Joel is very upfront about the fact that his textbook does not end with the typical 6-10 chapters of “special topics” isolated from the rest of the material, and I really appreciate that. Sure, those chapters might look appealing, but they are typically so bloated with information and details that it is like having (and paying for!) half of a biochemistry and sometimes an advanced organic chemistry textbook appended on. In seventeen years of teaching organic chemistry, I have never had time to actually do anything meaningful with any of them anyway. So they have never done me or the students much good. I really like having a textbook that we can cover from cover to cover, so to speak.

With a mechanistic organization, Joel includes relevant biochemistry material in sections titled “The Organic Chemistry of Biomolecules” at the end of all the appropriate chapters. For example, lipids come at the end of Chapter 2: “Three-Dimensional Geometry, Intermolecular Interactions, and Physical Properties.” They are right at home conceptually. Likewise, introduction of the D/L notation for carbohydrates and amino acids comes at the end of Chapter 5 where chirality is first introduced. Getting students to recognize and understand the connections and similarities between organic chemistry and biochemistry—despite their sometimes different language—can be a big hurdle at times. Do students ever ask you about the difference between peptide bonds and amide bonds? Such confusion is only natural, but it is also correctable by the improved juxtaposition of the differing terminology. In a more mechanism-based way, terpene biosynthesis becomes easier for students to understand when they see it right after alkene additions and carbocation rearrangements in Chapter 11. The intellectual synthesis of seemingly disparate topics by students is really facilitated by Joel’s integrated organization. I find that these sections are not unwieldy afterthoughts, but rather cogent nuggets of information that reinforce the main message.

Although I prefer to save detailed treatment of these biochemistry topics until the end of the course, I find that when we do cover them the students really get the connections. In fact, the last two weeks of the term are not only a preview of much that is to come in biochemistry but also a valuable review and reinforcement of the organic chemistry semester. They are forced to confront the topics together rather than separately. For the students not planning to take biochemistry, these classes become the icing on the organic chemistry cake. Either way, “less is more.” If the book had a whole chapter about DNA and RNA, for example, it would overwhelm us and defeat the purpose. The connections between organic chemistry and biochemistry are much more relevant and important to students than the exhaustive biochemical details. Organic chemistry does not need to become biochemistry to be relevant. Students need to understand organic chemistry to understand biochemistry and this is much more about process (i.e., mechanisms) than content.

So how does this textbook work for me as an instructor? In a word, perfect!

-Rick Bunt, Middlebury College

Click here to learn more about Prof. Bunt.

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