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OAT biology: what’s tested and how to practice

Biology is 40 of the 100 items in the Survey of the Natural Sciences, the first test you take on the Optometry Admission Test (OAT). The OAT Program describes that test as covering first-year college biology, general chemistry and organic chemistry, and OAT biology falls into five areas.

  • 40Biology items on the OAT
  • 90 minutesFor all 100 natural sciences items
  • April 13, 2022Date the biology outline last changed
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Updated October 2026 · Written from official sources, listed at the bottom of this page

What does OAT biology cover?

  • Cell and molecular biology: cell metabolism, including photosynthesis and enzymology; membrane transport and signal transduction; thermodynamics; mitosis and meiosis; cell structure and function; experimental cell biology; biomolecules.
  • Diversity of life: viruses, Archaebacteria, Eubacteria, Fungi, Protista, Plantae and Animalia.
  • Structure and function of systems: integumentary, skeletal, muscular, circulatory, lymphatic and immune, digestive, respiratory, urinary, nervous and sensory, endocrine and reproductive.
  • Genetics: molecular, human, classical and chromosomal genetics, genetic technology, developmental mechanisms, genomics, gene expression and epigenetics.
  • Evolution and ecology: natural selection, population genetics and speciation, animal behavior, and population, community and ecosystem ecology.

Each area also includes integrated relationships, questions that link topics. The Candidate Guide says advanced biology courses aren’t required.

Pacing biology on the natural sciences test

Biology shares the Survey of the Natural Sciences with 30 General Chemistry and 30 Organic Chemistry items, all in one 90-minute test. The Candidate Guide sets no separate time for biology, but you get a separate Biology score, and it counts toward both Total Science and the Academic Average.

How OAT scores are built →

OAT biology practice questions

The OAT Program’s Biology 201 module has 40 items written by OAT test constructors, the same as the biology part of its full practice test. You can buy it on its own. Prep companies sell their own biology question banks.

The official OAT practice test and module prices →OAT prep options →

Why the biology outline changed in 2022

In 2018 the Department of Testing Services ran three Biology Readiness surveys to find the core biology that first-year optometry students need to know. The updated specifications that came out of them were implemented on April 13, 2022, and added several topics that weren’t covered before. Prep material older than that may miss them.

Sources: OAT Program · Department of Testing Services and 3 more. Checked October 2026.

Rules and fees can change, so check the official site before your test.

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