The four MCAT sections are Chemical and Physical Foundations of Biological Systems, Critical Analysis and Reasoning Skills, Biological and Biochemical Foundations of Living Systems and Psychological, Social, and Biological Foundations of Behavior. MCAT stands for the Medical College Admission Test.
Each section measures a different combination of knowledge and reasoning. The three science sections connect concepts from several disciplines with scientific inquiry, while CARS focuses on understanding and analyzing passages without requiring specific outside knowledge.
The MCAT Sections at a Glance
- Chem/Phys connects chemistry, physics, biochemistry and biology to the functions of tissues, organs and organ systems.
- CARS measures comprehension and reasoning through passages from the humanities and social sciences rather than testing specific course content.
- Bio/Biochem covers biomolecules, cells, organ systems and the processes that allow living organisms to function and maintain stable internal conditions.
- Psych/Soc examines behavior, mental processes, social interaction, culture, inequality and the relationships between social conditions and well-being.
What the MCAT Tests
The Medical College Admission Test is a standardized, computer-based exam with four multiple-choice sections. According to the AAMC MCAT Essentials chapter on exam content, its content reflects concepts that medical school faculty, residents and students have rated as important to the success of entering students.
The science content comes from year-long general chemistry, organic chemistry, introductory physics and introductory biology courses, along with introductory biochemistry, psychology and sociology. Questions can connect material from more than one discipline, so knowing an isolated definition is not always enough. You also need to interpret information and reason through scientific problems.
The natural and social science sections organize their material around 10 foundational concepts. These broad ideas connect to more specific content categories and four scientific inquiry and reasoning skills. CARS follows a different framework. It tests comprehension and analysis using humanities and social sciences passages, and it does not require specific subject knowledge outside the passage.
The current version of the exam launched in April 2015 and tests concepts and skills that differ from those on the previous version. The MCAT has been part of medical school admissions for more than 90 years. Most medical schools in the United States and many in Canada require recent scores, while other health professions and graduate programs also accept them. The AAMC develops the exam with its member medical schools and administers it multiple times each year at hundreds of Pearson VUE sites in the United States, Canada and select locations worldwide.
You do not have to complete specified courses before registering and taking the exam, although its content is introductory college-level material. IMA’s MCAT registration guide covers the separate registration process.
The Four MCAT Sections in Test Order
The table below follows the AAMC MCAT content outline, retrieved Sept. 15, 2026. It brings together each section’s question count, testing time, format, disciplines or passage content, foundational concepts and reasoning targets.
| Section | Questions and time | Question format | Disciplines or passage content | Foundational concepts | Reasoning skills |
|---|---|---|---|---|---|
| Chemical and Physical Foundations of Biological Systems (Chem/Phys) | 59 questions, 95 minutes | Passage-based and discrete | First-semester biochemistry 25%; introductory biology 5%; general chemistry 30%; organic chemistry 15%; introductory physics 25% | Concept 4 40%; Concept 5 60% | Knowledge of scientific concepts and principles 35%; Scientific reasoning and problem-solving 45%; Reasoning about the design and execution of research 10%; Data-based and statistical reasoning 10% |
| Critical Analysis and Reasoning Skills (CARS) | 53 questions, 90 minutes | All passage-based | Humanities 50%; social sciences 50% | None; no specific content knowledge required | Foundations of Comprehension 30%; Reasoning Within the Text 30%; Reasoning Beyond the Text 40% |
| Biological and Biochemical Foundations of Living Systems (Bio/Biochem) | 59 questions, 95 minutes | Passage-based and discrete | First-semester biochemistry 25%; introductory biology 65%; general chemistry 5%; organic chemistry 5% | Concept 1 55%; Concept 2 20%; Concept 3 25% | Knowledge of scientific concepts and principles 35%; Scientific reasoning and problem-solving 45%; Reasoning about the design and execution of research 10%; Data-based and statistical reasoning 10% |
| Psychological, Social, and Biological Foundations of Behavior (Psych/Soc) | 59 questions, 95 minutes | Passage-based and discrete | Introductory psychology 65%; introductory sociology 30%; introductory biology 5% | Concept 6 25%; Concept 7 35%; Concept 8 20%; Concept 9 15%; Concept 10 5% | Knowledge of scientific concepts and principles 35%; Scientific reasoning and problem-solving 45%; Reasoning about the design and execution of research 10%; Data-based and statistical reasoning 10% |
The exam begins with Chem/Phys, followed by CARS, Bio/Biochem and Psych/Soc. The three science sections each contain 59 questions in 95 minutes. CARS contains 53 passage-based questions in 90 minutes. Science sections combine passage-based sets with independent questions, while every CARS question belongs to a passage set.
The percentages in the sections table above are AAMC targets rounded to the nearest 5%. They can vary between test forms because of question difficulty, passage-based question groupings and unscored field-test questions. For break information, total test-day length and the broader schedule, see IMA’s guide to how long the MCAT is.
Chemical and Physical Foundations of Biological Systems
What Chem/Phys Tests
Chem/Phys tests whether you can combine chemical and physical principles with scientific inquiry to solve problems involving biological systems. The AAMC Chem/Phys overview describes a section focused on the mechanical, physical and biochemical functions of human tissues, organs and organ systems, along with the principles that explain mechanisms in the body.
The tested disciplines include introductory biology, organic and inorganic chemistry, physics, first-semester biochemistry, introductory molecular biology and basic research methods and statistics. The approximate discipline targets are 30% general chemistry, 25% first-semester biochemistry, 25% introductory physics, 15% organic chemistry and 5% introductory biology.
Chem/Phys Foundational Concepts
Foundational Concept 4 accounts for about 40% of Chem/Phys. It concerns how living organisms transport materials, sense their environments, process signals and respond to changes through processes that can be understood using physical principles. The concept provides a basis for learning how physics applies to respiratory, cardiovascular and neurological functions in health and disease.
Foundational Concept 5 accounts for about 60%. It addresses how chemical interactions and reactions support an understanding of molecular activity in living systems. This material prepares medical students to connect principles of human chemistry with molecular and cellular functions in health and disease. Organic chemistry topics within this area include the structure, function and reactivity of biologically relevant molecules, which you can review in IMA’s guide to functional groups in organic chemistry.
You receive access to a periodic table while answering Chem/Phys questions.
Critical Analysis and Reasoning Skills
What CARS Tests
CARS tests how well you understand, analyze and evaluate what you read. The AAMC CARS overview describes it as a passage-based assessment developed to measure analysis and reasoning skills needed in medical school. You may need to identify an argument, examine the support for a claim, infer meaning or apply an idea to a new situation.
The questions also require attention to an author’s intentions, tone and word choices. This means effective reading involves more than recalling statements. You must determine how the passage is organized, how its ideas relate and what follows from its reasoning.
CARS Passages
CARS passages are typically 500 to 600 words. They can use sophisticated vocabulary, intricate writing styles and complex or thought-provoking ideas. The AAMC draws them from the kinds of books, journals and magazines college students are likely to read.
Half of the passages target humanities and half target social sciences. Humanities sources can cover architecture, art, dance, ethics, literature, music, philosophy, popular culture, religion and theater. These passages often focus on relationships among ideas and may have a conversational or opinionated tone.
Social sciences sources can include anthropology, archaeology, economics, education, geography, history, linguistics, political science, population health, psychology and sociology. They tend to use a more factual or scientific tone. Studies of diverse cultures can appear in either group.
You do not need prior coursework or specific content knowledge for the CARS section. Everything required to answer a question appears in the passage and question, even when the topic or writing style is unfamiliar.
The Three CARS Skills
The AAMC sets approximate targets for three CARS skills: Foundations of Comprehension at about 30% of the section, Reasoning Within the Text at about 30% and Reasoning Beyond the Text at about 40%. Reasoning Beyond the Text is the largest share, so practice should not stop at locating what a passage says.
Biological and Biochemical Foundations of Living Systems
What Bio/Biochem Tests
Bio/Biochem tests the processes that distinguish living organisms, including growth, reproduction, energy use, responses to environmental change and maintenance of a stable internal environment. The AAMC Bio/Biochem overview also emphasizes how cells and organ systems act independently and work together.
The section draws from introductory biology, organic and inorganic chemistry, first-semester biochemistry, cellular and molecular biology and basic research methods and statistics. Its approximate discipline targets are 65% introductory biology, 25% first-semester biochemistry, 5% general chemistry and 5% organic chemistry.
Bio/Biochem Foundational Concepts
Foundational Concept 1 makes up about 55% of the section. It concerns how the properties of biomolecules determine their roles in cellular structure and function and in processes that maintain life. This foundation prepares medical students to learn how biochemical, genetic and molecular cell functions support health and contribute to disease. Fuel molecule metabolism is part of this concept, and IMA’s comparison of glycolysis vs gluconeogenesis addresses two related pathways.
Foundational Concept 2 accounts for about 20%. It focuses on organized assemblies of molecules, cells and organs and how they interact to perform the functions of living organisms. This framework prepares students to study how cells grow and combine into tissues and organs that carry out biochemical and physiological functions.
Foundational Concept 3 contributes about 25%. It covers how systems of tissues and organs sense internal and external conditions, coordinate their functions and maintain a stable internal environment. It supports later learning about how the body responds to stimuli, maintains homeostasis and supports reproduction.
You also have access to a periodic table while answering Bio/Biochem questions.
Psychological, Social, and Biological Foundations of Behavior
What Psych/Soc Tests
Psych/Soc tests how psychological, social and biological factors affect perception, thought, behavior and behavior change. The AAMC Psych/Soc overview also includes social and cultural differences, social stratification, access to resources and their relationships with well-being.
The section draws from first-semester psychology and sociology, biology related to mental processes and behavior and basic research methods and statistics. Its discipline targets are about 65% introductory psychology, 30% introductory sociology and 5% introductory biology. In addition to the biology target, about 5% of the section consists of psychology questions with biological relevance.
Psych/Soc Foundational Concepts
Foundational Concept 6 accounts for about 25% and examines how biological, psychological and sociocultural factors shape perception, thought and reactions to the world. It supports learning about how cognitive and perceptual processes influence understandings of health and illness.
Foundational Concept 7 accounts for about 35% and focuses on influences on behavior and behavior change. It prepares students to examine how behavior may support health or increase disease risk. Foundational Concept 8, at about 20%, addresses self-identity, social thinking and interactions. This material provides a basis for learning how to communicate and collaborate with patients and health care teams.
Foundational Concept 9 makes up about 15% and concerns how cultural and social differences influence well-being. It prepares students to consider how social and demographic backgrounds can affect patients’ views of health, illness, health care teams and interventions.
Foundational Concept 10 accounts for about 5% and focuses on social inequality, stratification and access to resources. It establishes a basis for understanding how social and economic factors can affect access to care and the likelihood of maintaining health or recovering from disease.
The AAMC includes Psych/Soc because future physicians need to understand how behavior affects health and how to serve an increasingly diverse population. The section therefore connects individual mental processes with social conditions rather than treating psychology, sociology and biology as unrelated subjects.
Scientific Inquiry and Reasoning Skills
The three science sections test the same four scientific inquiry and reasoning skills. According to the AAMC, these reflect ways of thinking used by natural, behavioral and social scientists. They determine how you apply the content in a passage or question rather than adding another set of disciplines to memorize.
Knowledge of Scientific Concepts and Principles
Skill 1 tests your understanding of scientific concepts and the relationships between closely connected ideas. It represents about 35% of each science section.
Scientific Reasoning and Problem-Solving
Skill 2 asks you to reason about principles, theories and models, then evaluate explanations or predictions. At approximately 45%, it has the largest target share in each science section.
Reasoning About Research Design and Execution
Skill 3 tests your understanding of how research is designed and carried out, including your ability to reason about ethical issues in research. It accounts for about 10% of each science section.
Data-Based and Statistical Reasoning
Skill 4 asks you to identify patterns in tables, figures and graphs and draw conclusions from data. It also represents about 10%. Practice should include interpreting evidence as well as reviewing scientific content. The sections table above shows the shared targets in context.
MCAT Foundational Concepts and Content Categories
The AAMC MCAT content outline PDF, retrieved Sept. 15, 2026, identifies the 10 foundational concepts, the section and approximate share associated with each concept and the more specific content categories organized beneath them.
| Foundational concept | Section and share | AAMC concept statement | Content categories |
|---|---|---|---|
| Concept 1 | Biological and Biochemical Foundations of Living Systems (Bio/Biochem), about 55% of the section | Biomolecules have unique properties that determine how they contribute to the structure and function of cells, and how they participate in the processes necessary to maintain life. | 1A Structure and function of proteins and their constituent amino acids; 1B Transmission of genetic information from the gene to the protein; 1C Transmission of heritable information from generation to generation and the processes that increase genetic diversity; 1D Principles of bioenergetics and fuel molecule metabolism |
| Concept 2 | Biological and Biochemical Foundations of Living Systems (Bio/Biochem), about 20% of the section | Highly organized assemblies of molecules, cells, and organs interact to carry out the functions of living organisms. | 2A Assemblies of molecules, cells, and groups of cells within single cellular and multicellular organisms; 2B The structure, growth, physiology, and genetics of prokaryotes and viruses; 2C Processes of cell division, differentiation, and specialization |
| Concept 3 | Biological and Biochemical Foundations of Living Systems (Bio/Biochem), about 25% of the section | Complex systems of tissues and organs sense the internal and external environments of multicellular organisms, and through integrated functioning, maintain a stable internal environment within an ever-changing external environment. | 3A Structure and functions of the nervous and endocrine systems and ways in which these systems coordinate the organ systems; 3B Structure and integrative functions of the main organ systems |
| Concept 4 | Chemical and Physical Foundations of Biological Systems (Chem/Phys), about 40% of the section | Complex living organisms transport materials, sense their environment, process signals, and respond to changes using processes that can be understood in terms of physical principles. | 4A Translational motion, forces, work, energy, and equilibrium in living systems; 4B Importance of fluids for the circulation of blood, gas movement, and gas exchange; 4C Electrochemistry and electrical circuits and their elements; 4D How light and sound interact with matter; 4E Atoms, nuclear decay, electronic structure, and atomic chemical behavior |
| Concept 5 | Chemical and Physical Foundations of Biological Systems (Chem/Phys), about 60% of the section | The principles that govern chemical interactions and reactions form the basis for a broader understanding of the molecular dynamics of living systems. | 5A Unique nature of water and its solutions; 5B Nature of molecules and intermolecular interactions; 5C Separation and purification methods; 5D Structure, function, and reactivity of biologically-relevant molecules; 5E Principles of chemical thermodynamics and kinetics |
| Concept 6 | Psychological, Social, and Biological Foundations of Behavior (Psych/Soc), about 25% of the section | Biological, psychological, and sociocultural factors influence the ways that individuals perceive, think about, and react to the world. | 6A Sensing the environment; 6B Making sense of the environment; 6C Responding to the world |
| Concept 7 | Psychological, Social, and Biological Foundations of Behavior (Psych/Soc), about 35% of the section | Biological, psychological, and sociocultural factors influence behavior and behavior change. | 7A Individual influences on behavior; 7B Social processes that influence human behavior; 7C Attitude and behavior change |
| Concept 8 | Psychological, Social, and Biological Foundations of Behavior (Psych/Soc), about 20% of the section | Psychological, sociocultural, and biological factors influence the way we think about ourselves and others, as well as how we interact with others. | 8A Self-identity; 8B Social thinking; 8C Social interactions |
| Concept 9 | Psychological, Social, and Biological Foundations of Behavior (Psych/Soc), about 15% of the section | Cultural and social differences influence well-being. | 9A Understanding social structure; 9B Demographic characteristics and processes |
| Concept 10 | Psychological, Social, and Biological Foundations of Behavior (Psych/Soc), about 5% of the section | Social stratification and access to resources influence well-being. | 10A Social inequality |
The concepts table above can serve as the structure for your content review. Begin with the broad concept statement so you understand how the topics connect. Then use its content categories to identify the specific areas you need to review, rather than treating a long collection of terms as unrelated material.
As you study a category, connect it to the discipline knowledge and reasoning skills required by its section. For example, a category may draw on biochemistry knowledge while a question asks you to interpret an experiment or evaluate data. Marking both the content area and the reasoning task can help you diagnose whether a missed question came from a knowledge gap or difficulty applying what you knew.
How the MCAT Sections Are Scored
Each MCAT section receives a scaled score from 118 to 132, with 125 as the midpoint. The four section scores combine into a total from 472 to 528, with a midpoint of 500. IMA’s MCAT score calculator guide explains the scoring scale and how to interpret practice results.
The AAMC does not subtract points for wrong or unanswered questions and advises you to answer every question. Each section also contains field-test questions considered for possible future use. Those questions do not contribute to your score.
If you are looking for a passing number, the AAMC calls it a myth that you need a certain MCAT score to be a competitive applicant, because admissions officers use MCAT scores together with experiences, attributes and transcripts. IMA’s guide to what MCAT score you need for medical school discusses that question without treating one number as a universal threshold.
How to Prepare for Each MCAT Section
Start With the Content Outline Course
The free What’s on the MCAT Exam Content Outline Course includes the complete outline, links to open-access textbooks and Khan Academy lessons and 120 questions from the retired Official Guide to the MCAT Exam. Use it to compare your current knowledge with the concepts and categories tested in each section. IMA’s guide to free MCAT prep resources can help you place these materials within a study plan.
Use the Sample Questions to Learn the Framework
The free MCAT Sample Question Guide contains 12 questions, with three from each section. Every question includes the correct answer and an explanation that identifies the relevant foundational concepts and skills. The science examples demonstrate how knowledge and reasoning work together, including questions that use tables, charts or graphs. The CARS examples show how comprehension, inference and application appear in question form.
Practice Science Sections by Section and Subject
Section Bank Volumes 1 and 2 each contain 300 questions, divided into 100 questions for each science section. The Independent Question Bank instead organizes independent questions across biochemistry, biology, general chemistry, organic chemistry, physics, psychology and sociology. IMA’s MCAT practice test guide explains how section-level practice fits with broader exam practice.
Choose practice based on the weakness you are trying to address. Section-based sets can show how several disciplines and reasoning skills work together. Subject-based independent questions can help you isolate a narrower content gap. For CARS, focus on passage comprehension, the author’s reasoning and applying ideas without adding outside assumptions.
Build Your Section-by-Section Study Plan
Start by comparing each section with your current coursework and practice results. Use the foundational concepts to organize what you review, then test whether you can apply that knowledge through passages, experiments and data. CARS needs a separate reading and reasoning routine because additional science memorization does not address its central task.
For practical next steps, use IMA’s guide on how to study for the MCAT to shape your approach, then map the work onto an MCAT prep timeline that gives every section consistent attention.
Frequently Asked Questions
What Are the Four Sections of the MCAT?
The four sections are Chemical and Physical Foundations of Biological Systems, Critical Analysis and Reasoning Skills, Biological and Biochemical Foundations of Living Systems and Psychological, Social, and Biological Foundations of Behavior. They appear in that order on the exam.
How Many Questions Are in Each MCAT Section?
Chem/Phys, Bio/Biochem and Psych/Soc each contain 59 questions, while CARS contains 53. The science sections combine passage-based sets and independent questions, but all CARS questions are passage-based.
What Does MCAT Stand For?
MCAT stands for the Medical College Admission Test. It is a standardized, computer-based exam with four multiple-choice sections.
Which MCAT Sections Include Biochemistry?
Chem/Phys and Bio/Biochem both include first-semester biochemistry. Biochemistry represents an approximate 25% discipline target in each of those sections, although the surrounding concepts and questions differ.
Do You Need Outside Knowledge for the CARS Section?
No. Everything needed to answer a CARS question is contained in its passage and question, so the section does not require specific subject knowledge or additional coursework. You still need to analyze the author’s ideas, tone, evidence and reasoning carefully.
Do You Get a Periodic Table on the MCAT?
Yes. You have access to a periodic table while answering Chem/Phys and Bio/Biochem questions. You still need to know how to apply chemical relationships and principles because the table serves as a reference.
What Are the MCAT Foundational Concepts?
The MCAT foundational concepts are 10 broad scientific ideas that organize content in the three science sections. Concepts 1 through 3 belong to Bio/Biochem, concepts 4 and 5 belong to Chem/Phys and concepts 6 through 10 belong to Psych/Soc. Each concept contains more specific content categories.
Is There a Passing Score on the MCAT?
MCAT results are scaled scores, from 118 to 132 for each section and 472 to 528 in total. The AAMC does not tie competitiveness to one number; it says schools weigh your MCAT results with the rest of your application.
