MCAT Bio/Biochem
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ExploreAbout this exam
The MCAT Biological and Biochemical Foundations of Living Systems section is the bio/biochem portion of the Medical College Admission Test, the standardized exam the AAMC administers for people preparing to apply to medical school. The AAMC reports that roughly 95,000 people per year take the MCAT exam, and that aspiring doctors apply to medical school through its AMCAS program. This section tests how well you reason with living systems at the molecular and cellular level rather than how much trivia you have memorized. Our practice content is organized into four domains of equal weight: biomolecules and the chemistry of living systems; cells and cell division; structure and function of proteins and enzymes; and bioenergetics and metabolism. Questions are multiple choice and self-contained, so each one gives you everything you need to reason to an answer. To prepare, work domain by domain, prioritize the areas where your science coursework is weakest, and practice extracting the logic of an experiment or pathway from the passage rather than recalling isolated facts. This page is an independent study resource and is not affiliated with or endorsed by the AAMC. Verify all official policies, including registration, fees, scoring, and testing accommodations, directly with the AAMC.
What you'll study
About MCAT Bio/Biochem preparation
What is the format of the Bio/Biochem section?
It is a multiple-choice section. The AAMC does not publish section-level item counts or timing on the pages we could verify, so we do not quote a number here. Check the AAMC's MCAT Essentials and MCAT FAQs for the current structure before you build a timing strategy around any figure.
How hard is this section compared with the others?
Most students find it demanding because it combines biochemistry, molecular biology, and physiology and expects you to apply them to unfamiliar experimental data. Difficulty comes less from obscure facts than from reasoning speed. Practicing passage-based questions under time pressure is the most reliable way to raise your score.
Can I retake the MCAT if my Bio/Biochem score is low?
Retake rules, limits, and any waiting periods are set by the AAMC and change over time. We could not verify current policy from our sources, so confirm the rules in the MCAT Essentials and MCAT FAQs on the AAMC site before scheduling a second attempt.
How should I order my studying across the four domains?
Start with biomolecules and protein/enzyme structure, since amino acid chemistry and enzyme kinetics underpin metabolism. Then move to bioenergetics and metabolism, and integrate cells and cell division alongside them. Finish with mixed practice that forces you to switch domains quickly, mirroring how the real section interleaves topics.
What are the most common mistakes test takers make?
Three recur: memorizing pathways without understanding regulation and energetics, ignoring the passage in favor of outside knowledge, and misreading figures and graphs. A fourth is skipping amino acid and enzyme-kinetics fluency, which slows every metabolism question. Practice explaining each answer choice's reasoning, not just identifying the correct one.
How many questions are on the exam and how long does it take?
The AAMC does not list total question counts or section timing on the pages we verified, so we report no figure. Because the exam is periodically revised, consult the current MCAT Essentials and the AAMC's MCAT FAQs rather than older prep materials for length and timing.
How much does it cost to register, and are fee waivers available?
Registration fees and fee assistance details are set by the AAMC and are not stated in our verified sources, so we do not quote an amount. The AAMC does describe a Fee Assistance Program that provides reduced or waived fees; check current eligibility and amounts on the AAMC site.
Is this site affiliated with the AAMC?
No. We are an independent study platform. Our questions are original and self-contained, and we do not reproduce AAMC materials. For official registration, scoring, accommodations, and test-day policies, use the AAMC's own MCAT pages and publications.
How do I know whether my practice scores are on track?
Track accuracy by domain rather than by a single overall percentage, and note whether errors come from content gaps or from misreading passages. Steady improvement in your weakest domain is the strongest signal. We do not publish score conversions, so use AAMC practice materials for official-style scoring.