What Is on the MCAT?


Scoring well on the MCAT is a major key for med school acceptance. However, earning a high score is a challenge without knowing what is on the MCAT. To ensure you know what to study and reach your maximum score, this article outlines what is covered on the MCAT.

What Is the Structure on the MCAT?

To be successful in the clinic, doctors need an array of knowledge and skills. The MCAT assesses test-takers’ skill diversity through its four sections:

  1. Chemical and Physical Foundations of Biological Systems (“Chem/Phys”)
  2. Critical Analysis and Reasoning Skills (“CARS”)
  3. Biological and Biochemical Foundations of Living Systems (“Bio/Biochem”)
  4. Psychological, Social, and Biological Foundations of Behavior (“Psyc/Soc”)

The AAMC outlines what is on the MCAT’s four sections. Its descriptions are thorough and, therefore, lengthy. Below is my breakdown:

CARS Skills

The CARS section presents test-takers with non-scientific passages (50% humanities and 50% social sciences) and challenges them with questions that demand varying levels of comprehension. Below are the skills that the CARS section evaluates.

  1. Skill 1: Foundations of Comprehension30% of questions

These questions test if you are able to make sense of the author’s writing (Think literal comprehension questions on the SAT or ACT). The answers to these questions will be directly in the passage (although relevant information in the passage may be worded differently than the answer choice).

  1. Skill 2: Reasoning Within the Text30% of questions

These questions challenge you to evaluate elements of the passage at a higher level; assessing the author’s argument, tone, theme, language choice, audience, assumptions, biases, logic errors, or purpose for including information.

  1. Skill 3: Reasoning Beyond the Text40% of questions

These questions demand that you understand the author’s key ideas and then run with them. Often, this means applying the author’s claims to a novel situation or seeing how new information will affect the author’s claims.

Non-CARS Skills

The MCAT’s three non-CARS sections (Bio/Biochem, Chem/Phys, Psyc/Soc) evaluate the following skills:

  • Skill 1: Knowledge of Scientific Concepts and Principles35% of questions

These questions test how well you know concrete material (i.e. what is in your textbooks). Almost all non-passage-based (“discrete”) questions fall into this category.

  • Skill 2: Scientific Reasoning and Problem Solving45% of questions

These questions demand that you know concrete knowledge but also take your knowledge one step further, often to make a prediction or challenge a hypothesis. These questions are quite varied in format, so be on your toes.

  • Skill 3: Reasoning About the Design and Execution of Research10% of questions

These questions demand that you evaluate the pertinence, validity, or ethics of experimental procedures. Be sure to be totally confident in experiment-related terminology.

  • Skill 4: Data-Based and Statistical Reasoning10% of questions

These questions challenge test-takers to identify and interpret trends in tables, figures, and graphs. Be sure to know statistics-related terms (mean, median, mode, etc).

  • Additional: Mathematical Concepts and Techniques

Some MCAT questions (primarily those on the Chem/Phys section) demand test-takers to use math to answer a question, most commonly using a formula. However, there is no calculator on the MCAT, so be sure to get comfortable doing math questions by hand—logs, unit conversions, ratios, simple trig, multiplication, division, etc.

Bio/Biochem Content

59 questions compose the Bio/Biochem section: 44 passage-based questions and 15 discrete questions. The content is 65% biology, 25% biochemistry, 5% organic chemistry, and 5% general chemistry.

Below are the three Bio/Biochem foundational concepts outlined by the AAMC:

  • Foundational Concept 1: Biomolecule Structure and Function55% of questions

These questions cover the structures and functions of amino acids, proteins, nucleotides, RNA, DNA, lipids, and sugars. Topics also include biomolecule-related processes like DNA replication and protein production.

  • Foundational Concept 2: Molecule, Cell, and Organ Interactions20% of questions

These questions focus on properties of organelles, cell-specific processes (mitosis, meiosis, and more), cell junctions, ionic gradient maintenance, viruses, prokaryotes, the cell cycle, embryogenesis, and cell differentiation.

  • Foundational Concept 3: High-Level Somatic Organization25% of questions

These questions test your understanding of the nervous and endocrine systems’ effects on other parts of the body. Other topics include the other organ systems: respiratory, circulatory, immune, etc.

Chem/Phys Content

59 questions compose the Chem/Phys section: 44 passage-based questions and 15 discrete questions. The content is 30% general chemistry, 25% physics, 25% biochemistry, 15% organic chemistry, and 5% biology.

Below are the two Chem/Phys foundational concepts outlined by the AAMC:

  • Foundational Concept 1: Physical Properties Impact Physiology40% of questions

These questions cover motion, energy, fluids, electricity, magnetism, electrochemistry, light, sound, optics, atomic decay, and stoichiometry. You will apply physics-related knowledge and formulas to make predictions about human physiology.

  • Foundational Concept 2: Physics Determines Biomolecular Properties60% of questions

These questions demand an understanding of solutions, acids/bases, intermolecular forces, separation/purification, biomolecular structure, functional groups, enzyme kinetics, bond types, and thermodynamics. You will apply these ideas to explain mechanisms behind somatic function and diseases.

Psyc/Soc Content

59 questions compose the Psyc/Soc section: 44 passage-based questions and 15 discrete questions. The content is 65% introduction biology, 30% sociology, and 5% psychology.

Below are the five Psyc/Soc foundational concepts outlined by the AAMC:

  • Foundational Concept 1: Psy/Soc Factors Influence Interactions25% of questions

These questions demand you know how one perceives his/her environment, makes sense of perceived information, and responds. Topics include sensory organs, perception, attention, cognition, consciousness, memory, language, emotion, and stress.

  • Foundational Concept 2: Human Behavior35% of questions

These questions focus on influencers of behavior and behavioral change. Topics include the nervous system, personality, psychological disorders, motivation, attitude, social processes, socialization, and learning theories.

  • Foundational Concept 3: Self-Image and Social Interactions20% of questions

These questions cover the development of self-image and the drivers of social interactions. Topics include identity formation, prejudice, stereotypes, self-presentation, social behavior, and discrimination.

  • Foundational Concept 4: Cultural and social differences15% of questions

These questions test knowledge on social structures, demographic characteristics, and processes that define societies. Topics include sociological theories, culture, and demographic-related processes.

  • Foundational Concept 5: Social Stratification and Resource Allocation5% of questions

These questions focus on societal issues can lead to adverse outcomes, particularly for vulnerable populations. Topics include spatial inequality, social class, as well as health and health care disparities.

Section-Specific Pro Tips

When I retook the MCAT, I scored a 519 (131 Chem/Phys, 127 CARS, 131 Bio/Biochem, 130 Psyc/Soc). While more general study tips can be found in How to Study for the MCAT, here is some advice regarding test preparation for each of the sections:


  • Memorize your formulas; you will miss questions if you misremember a formula.
  • Work fast. This was my most time-constrained section.
    • I did not finish Chem/Phys the first time I took the MCAT.
    • Working fast is easier if you know formulas well.
  • Rounding (within reason) is generally necessary to complete a math question in a reasonable amount of time.


  • Purchase and regularly study with the AAMC practice questions.
  • Even if you are a strong CARS student, still practice a few times a week.
    • By the end of studying, I was scoring between 128 and 130 in CARS on practice tests, but I still scored a 127 on actual test day (quite a bit lower than my other sections). I think my score would have been more stable with additional practice.
  • Take time to review exactly why you missed specific questions.


  • Memorization is always necessary. In particular, be sure to memorize:
    • Structures and characteristics of all 20 amino acids
    • Structures and enzymes of glycolysis and Krebs cycle steps
  • Don’t just be familiar with the content in your review book; know it backwards and forwards.
    • This is how I jumped from a 128 to a 131 on my retake.


  • Know the differences between related ideas and vocabulary terms.
    • In addition to Psyc/Soc terms, master experiment-related terms, which may actually appear at the end of your physics review book.
  • Memorize lists whenever possible.
    • Many topics (stages of psychosocial development, personality disorders, etc.) include long lists. Forgetting one item in the list can lead you to miss a question, so be sure to know the content well.
    • Use mnemonic devices to learn lists more easily.
  • Cross-reference different sources.
    • With so much vocab that could appear on the Psyc/Soc section, I have not yet come across a single study source that covers everything.
    • Learn everything in one review source, and then look through a couple others to see what terms or ideas the first source missed.

Making Sense of What Is on the MCAT

With so much possible content on the MCAT, preparing can be overwhelming. However, this article broke down how the AAMC organizes the key ideas, allowing you to better know what is on the test. After reading this article, you now know what is on the MCAT. Now it’s time for the next step—learning it.