Organic Chemistry on the MCAT – Focus on the Fundamentals
- Jan 16, 2018
- MCAT Blog, MCAT Chemistry, MCAT Organic
Organic chemistry is one of the most common subjects that students identify as a source of anxiety when preparing for the MCAT. However, on average, it will only comprise ~5% of the test: 15% of the Chemical and Physical Foundations section, 5% of the Biological and Biochemical Foundations Section, and 0% of the remaining two sections. Therefore, it is a topic you need to address head-on – which is why we cover it in-depth in our online MCAT course – but on the other hand, it doesn’t necessarily have to play the same intimidating role that it might occupy in your memories of college. To efficiently study o-chem for the MCAT, we suggest taking three major steps: first, work to understand the differences between how o-chem is taught in college classes versus how it is tested on the MCAT; second, organize MCAT-relevant o-chem content around a few major themes; and third, learn those fundamentals inside and out as a way to help extend your knowledge base to include other o-chem topics.
O-chem in college versus on the MCAT
This can be good news or bad news depending on how you felt about your o-chem coursework, but the MCAT tests organic chemistry in a very different way than most college courses do. In particular, most college-level courses primarily focus on organic synthesis; it’s as if their ultimate goal is to prepare you to be a practicing laboratory chemist, working to synthesize new and valuable compounds. In contrast, the MCAT generally focuses on o-chem as appropriate for future physicians. This means, among other things, focusing on aspects of o-chem that impact pharmacology, help explain crucial metabolic pathways and yield insight into common reactions and properties of biologically relevant chemicals.
With all the above points in mind, we can divide MCAT o-chem into a few major themes: nomenclature (or knowing what things are), following the electrons, understanding where molecules are in space, and everything else.
The good news is that, unlike quizzes you may remember from o-chem class, you won’t be required to independently name organic molecules. However, you have to know what molecules are called, as a pure nomenclature-based question is certainly conceivable, and you also must know the basic physical and chemical properties associated with various functional groups. Don’t neglect these aspects of o-chem review just because they’re not as intellectually challenging as aldol reactions; on Test Day, you really don’t want to lose points or even time because of confusion about amides versus imines, or due to confusion about whether a carboxylic acid or an amine will have a higher boiling point.
Follow the electrons
A surprising number of o-chem topics boil down to following the electrons. Whenever you’re studying an o-chem topic, try to bring it back to the basic principle of looking at where full or partial charges accumulate and how they interact. This can be helpful for topics ranging from chemical/physical properties, which are due to intermolecular interactions that in turn are shaped by charge, all the way to making sense of mechanisms. Mechanisms are a challenging part of o-chem, but on the MCAT you will only be asked about them in a multiple-choice context. This means that on one hand, you don’t have to be responsible for drawing out every single step, but on the other hand, you must be absolutely clear about which atom is attacking which other atom, whether it is a nucleophile or an electrophile, and so on. The path to understanding this for any reaction you study is to relentlessly ask: where are the electrons going?
Where are the atoms in space?
The term “stereochemistry” is a fancy word for this, and stereochemistry is extremely important for the MCAT because it has important links to biochemistry (see carbohydrate chemistry, for instance) and even physiology/pharmacology, as many receptors in the human body are stereospecific. Some must-knows in this context include the terminology relating to isomerism, the use of terms like cis and trans, the E/Z system for the stereochemistry of double bonds, the ability to identify chiral centers, and the ability to classify chiral centers as R or S. Invest the time and effort needed to make sure that you really get this – consider using a molecular model kit, draw it out, make friends or family listen to your explanation of chirality, and so on.
All the other topics within organic chemistry can be classified under “everything else.” This isn’t to say they aren’t important: there are absolutely o-chem topics that are fair game for the MCAT that fall into the domain of “everything else” (aldol synthesis, anyone?). However, if you build rock-solid foundations in terms of nomenclature, electron tracking, and stereochemistry, you’ll find that you have an easier time tackling these topics. Moreover, the three big topics that we discussed are a predictable source of very gettable questions on the MCAT, so be sure to give them the emphasis they deserve.
Finally, a reminder: you can do this! O-chem is a real challenge but can be surmounted.
If you need more help with ochem, we can help! Schedule a free consultation with one of our Academic Managers to see which MCAT prep style is right for your goals.
We wish you the best of luck in your test prep process!
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