MCAT® Chemical and Physical Foundations of Biological Systems (CPBS)

MCAT Chemical & Physical Sciences Section Overview

Subject Breakdown

The  Chemical and Physical Foundations of Biological Systems (CPBS) section is the second section to appear on the MCAT exam is worth 25% of your total score. This section tests your knowledge of foundational concepts in physics and Chemistry, expecting students to use their scientific inquiry, reasoning, research, and statistic skills to solve complex problems.

  • Introductory General Chemistry - 30%
  • Introductory Physics - 25%
  • First-Semester Biochemistry - 25%
  • Introductory Organic Chemistry - 15%
  • Introductory Biology - 5%

Question Structure

This section contains 10 passages that often include experimental details followed by the presentation of the resulting data in the form of tables, graphs, or figures. You will need to interpret the results of the experiment, apply equations, and perform calculations to connect the results to broader scientific concepts.

  • 59 multiple-choice questions.
  • 10 passages each with 4 to 6 associated questions.
  • 15 independent or "discrete" questions.

Timing & Pro Tips

Students have only 95 minutes to complete this challenging MCAT section, and many find this time constraints to be very challenging.

  • Spend less than 3 minutes reading each passage.
  • Don’t get bogged down by small details.
  • Focus on any equations, graphs or tables of results provided.
  • Calculators are NOT permitted, so use rounding and estimation to simplify calculations.
  • Don't forget you have access to the Periodic Table.

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The Chemical and Physical Sciences section can be extremely challenging. Students often feel overwhelmed by the sheer volume of material and end up wasting time on irrelevant details that are unlikely to appear on the test. Hence, knowing the right strategies for this section is the key to significantly improving your MCAT score.

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MCAT® Chemical & Physical Sciences: Concepts Tested

Foundational Concept 4:

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

Foundational Concept 5:

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