Biological and Biochemical Foundations of Living Systems: Overview

The Biological and Biochemical Foundations of Living Systems section asks you to solve problems by combining your knowledge of biological and biochemical concepts with your scientific inquiry and reasoning skills. This section tests processes that are unique to living organisms, such as growing and reproducing, maintaining a constant internal environment, acquiring materials and energy, sensing and responding to environmental changes, and adapting. It also tests how cells and organ systems within an organism act independently and in concert to accomplish these processes, and it asks you to reason about these processes at various levels of biological organization within a living system.

This section is designed to:
  • test introductory-level biology, organic chemistry, and inorganic chemistry concepts;
  • test biochemistry concepts at the level taught in many colleges and universities in first-semester biochemistry courses;
  • test cellular and molecular biology topics at the level taught in many colleges and universities in introductory biology sequences and first-semester biochemistry courses;
  • test basic research methods and statistics concepts described by many baccalaureate faculty as important to success in introductory science courses; and
  • require you to demonstrate your scientific inquiry and reasoning, research methods, and statistics skills as applied to the natural sciences.
Test Section Number of Questions Time
Biological and Biochemical 
Foundations of Living Systems
(note that questions are a
combination of passage-based
and discrete questions)
95 minutes
During the actual exam, you will have access to the periodic table while answering questions in this section of the exam.

You may wonder how much biochemistry you'll see on this section of the MCAT exam, how many questions you'll get about a particular foundational concept, or how the scientific inquiry and reasoning skills will be distributed on your exam. The questions that you see are likely to be distributed in the ways described below. These are the approximate percentages of questions you'll see on a test for each discipline, foundational concept, and reasoning skill.

  • First-semester biochemistry, 25%
  • Introductory biology, 65%
  • General chemistry, 5%
  • Organic chemistry, 5%
Foundational Concept:
  • Foundational Concept 1, 55%
  • Foundational Concept 2, 20%
  • Foundational Concept 3, 25%
Scientific Inquiry and Reasoning Skill:
  • Skill 1, 35%
  • Skill 2, 45%
  • Skill 3, 10%
  • Skill 4, 10%
*These percentages have been approximated to the nearest 5% and will vary from one test to another for a variety of reasons. These reasons include, but are not limited to, controlling for question difficulty, using groups of questions that depend on a single passage, and using unscored field-test questions on each test form.