Before you can apply to medical school, you need to complete a set of foundational science courses. These prerequisites do double duty: they satisfy admissions requirements and they build the knowledge base the MCAT tests. This guide walks through each required course, what to expect, and concrete strategies for earning the strong grades that make up your all-important science GPA.
Medical schools calculate a separate science GPA (often called BCPM — biology, chemistry, physics, and math) in addition to your overall GPA. Admissions committees scrutinize this number because it predicts how you'll handle the science-heavy medical curriculum. A strong science GPA can offset other weaknesses; a weak one is hard to explain away. Treat every prerequisite as if it matters, because it does.
Gen chem is the foundation everything else builds on. You'll cover atomic structure, stoichiometry, bonding, gases, thermodynamics, kinetics, equilibrium, acids and bases, and electrochemistry. The biggest predictor of success is doing problems — lots of them — rather than re-reading the textbook. Go to office hours early; gen chem professors are typically among the most approachable on campus, and showing up signals seriousness.
Bio I leans heavily on cell biology, genetics, and molecular biology — the "memorization" course where spaced-repetition flashcards (Anki) pay off enormously. Bio II shifts toward evolution, ecology, physiology, and organ systems, which is more conceptual. Connect everything you can to human health, because that's the lens the MCAT uses.
Orgo has a fearsome reputation as a "weed-out" course, but the students who struggle are almost always the ones who fall behind early. The secret is to start from day one and to draw mechanisms by hand, repeatedly, rather than memorizing them. Orgo is a language; fluency comes from practice. YouTube channels like The Organic Chemistry Tutor and Professor Dave Explains are lifesavers, and a study group turns a brutal solo grind into a manageable team effort.
Physics I covers mechanics, energy, waves, and fluids; Physics II covers electricity, magnetism, circuits, and optics. Most pre-med programs accept algebra-based physics, though some schools prefer calculus-based — check your targets. Draw a free-body diagram for every mechanics problem and don't just memorize formulas; understand when each one applies. MCAT physics is conceptual, so the "why" matters more than heavy computation.
If there's one course to take seriously, it's biochem — it's the most heavily tested subject on the MCAT. You'll learn the 20 amino acids cold, enzyme kinetics, and the major metabolic pathways (glycolysis, the citric acid cycle, the electron transport chain). Take it as close to your MCAT as your schedule allows so the material is fresh.
| Course | Why it's required |
|---|---|
| Math (Calculus or Statistics) | Statistics is more practical for research and reading studies; some schools specifically require calculus. Check your target schools. |
| Psychology | An entire MCAT section. Take the course rather than self-studying it. |
| Sociology | Paired with psychology on the MCAT; covers social structures, inequality, and demographics. |
| English / Writing | Strong writing improves your CARS score, personal statement, and secondary essays. Many schools require two semesters. |
There's no single correct order, but a common, sane sequence is gen chem and bio first (they're prerequisites for orgo and biochem), then orgo and physics, then biochem last so it's fresh for the MCAT. Post-bacc students can complete the whole sequence in about two years with two courses per semester plus summer sessions.
Here's the kind of schedule that keeps a two-science-course-per-term load manageable while finishing in time to study for the MCAT afterward. Adjust to your own pace — finishing a semester later is far better than tanking a GPA by overloading.
| Term | Courses |
|---|---|
| Year 1 — Fall | General Chemistry I + lab, Biology I + lab |
| Year 1 — Spring | General Chemistry II + lab, Biology II + lab |
| Year 1 — Summer | Psychology, Statistics (lighter, non-lab courses) |
| Year 2 — Fall | Organic Chemistry I + lab, Physics I + lab |
| Year 2 — Spring | Organic Chemistry II + lab, Physics II + lab, Sociology |
| Year 2 — Summer | Biochemistry, then begin dedicated MCAT study |
This is one of the most common questions, and the honest answer is: they count, but with nuance. Most medical schools accept prerequisite credits from accredited community colleges. However, some admissions committees view upper-level science taken at a four-year university more favorably, and a few schools explicitly prefer (or require) that core prerequisites be completed at a four-year institution. If cost or access makes community college the right call — and for many post-baccs it is — take the introductory courses there and consider taking at least some upper-level science (like biochemistry) at a four-year school to demonstrate you can handle that rigor.
Policies vary widely. Some schools accept AP credit for prerequisites if it appears on your college transcript; many do not, or they require you to take a higher-level course in the same department to "replace" it. The safest approach: if you placed out of, say, General Chemistry I with AP credit, take an additional upper-level chemistry course so your transcript clearly shows college-level work in that area. Always verify each target school's specific AP policy.
If you earned a C− or below in a prerequisite, retaking it can be worth it — but understand how the math works. AMCAS (the MD application) includes both the original and the retake grade in your GPA calculation; it does not replace the old grade the way some undergraduate institutions do. AACOMAS (DO) has historically used grade replacement, though this has changed over time, so check the current policy. The takeaway: a retake demonstrates growth and refreshes the knowledge, but for MD applicants it dilutes rather than erases a low grade. Doing it right the first time is always the cheaper path.
Most schools expect roughly a year each of general chemistry, organic chemistry, biology, and physics (all with labs), plus biochemistry, and usually English/writing, math, psychology, and sociology. That works out to around 13–15 courses, though the exact count depends on the school.
Yes — you can apply with prerequisites "in progress," as long as you'll complete them before matriculation. Just make sure your MCAT reflects the content you've learned, since the test assumes you know it.
No. A strong upward trend and a solid science GPA (think 3.5+ for competitive MD applicants) matter more than perfection. One rough semester explained by a clear story is survivable; a pattern of low science grades is harder.
Be cautious. Online lecture courses are increasingly accepted (especially post-2020), but online lab credit is viewed more skeptically by some schools. Prefer in-person or hybrid labs when you can.