Biology E/M Subject Test

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Order the Official SAT Subject Test Study Guide in Biology and get two full-length practice tests, detailed answer explanations, tips, and more.

Taking the SAT Subject Test in either Biology Ecological or Biology Molecular can help you indicate to colleges that you are interested in focusing on science. The Biology Subject Test assesses your understanding of the major concepts of biology typically learned in high school and is an excellent way to showcase your achievements.

Start practicing online with general Biology questions

The Biology Ecological (Biology-E) test leans more toward biological communities, populations, and energy flow.

Start practicing online with Biology-E questions

The Biology Molecular (Biology-M) test is more geared toward biochemistry, cellular structure and processes, such as respiration and photosynthesis.

Start practicing online with Biology-M questions

Video Lessons from Khan Academy

Use the free Khan Academy® lessons in this playlist to study for both the Biology Ecological and Biology Molecular Subject Tests.

Test Basics

Scoring, Timing, Number of Questions
Points Minutes Questions
200-800 60 80 (Multiple Choice)

60 of the 80 questions are common to both Biology E and M, followed by 20 specialized questions for each section.


Important Notes

  • Offered in August, October, November, December, May, and June.
  • Calculator use not permitted
  • Problem solving requires simple numerical calculations
  • Measurements are expressed in the metric system

Getting Ready for the Test

Skills (for both E and M) Approximate % of Test
Fundamental concepts and knowledge 30%
Application 35%
Interpretation 35%
  • Ability to recall and understand the major concepts of biology and to apply the principles learned to solve specific problems in biology
  • Understanding of simple algebraic concepts, including ratios and direct and inverse proportions, and the ability to apply such concepts to solving word problems
  • Ability to organize and interpret results obtained by observation and experimentation and to draw conclusions or make inferences from experimental data, including data presented in graphic or tabular form or both
  • Familiarity with the metric system of units
  • One-year introductory college preparatory course in biology
  • One-year course in algebra
  • Experience in the laboratory
Content Approximate % of Test
  E M

Cellular and molecular biology

Cell structure and organization, mitosis, photosynthesis, cellular respiration, enzymes, biosynthesis, biological chemistry

15% 27%


Energy flow, nutrient cycles, populations, communities, ecosystems, biomes, conservation biology, biodiversity, effects of human intervention

23% 13%


Meiosis, Mendelian genetics, inheritance patterns, molecular genetics, population genetics

15% 20%

Organismal biology

Structure, function, and development of organisms (with emphasis on plants and animals), animal behavior

25% 25%

Evolution and diversity

Origin of life, evidence of evolution, patterns of evolution, natural selection, speciation, classification and diversity of organisms

22% 15%

Download the SAT Subject Tests Student Guide (.pdf/6.3 MB) for more information on the topics.

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Additional Things to Know

How to Choose between Biology-E (Ecological) and Biology-M (Molecular)

  • Take Biology E if you feel more comfortable answering questions about biological communities, populations, and energy flow.
  • Take Biology M if you feel more comfortable answering questions about biochemistry, cellular structure and processes, such as respiration and photosynthesis.
  • Indicate choice of Biology E or Biology M by filling in the appropriate circle on your answer sheet for the test you have chosen to take on test day. You must indicate Biology E or Biology M on your answer sheet on test day for the test to be scored correctly
  • You cannot take both tests on the same test date, but you can take them on two different test dates.

Please note that this test reflects what is commonly taught in high school. Due to differences in high school classes, it’s likely that most students will find questions on topics they’re not familiar with. This is nothing to worry about. You do not have to get every question correct to receive the highest score (800) for the test. Many students do well despite not having studied every topic covered.