• 55 questions

ADA OAT Practice Test

Unofficial Optometry Admission Test practice in biology, chemistry, physics and quantitative reasoning, with a timed mode.

Which hormones does the adrenal medulla secrete?

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Exam mode: 50 questions, 45 minutes.

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Unofficial practice questions, not affiliated with the American Dental Association or ASCO. Bank checked October 11, 2026.

The real test, as the OAT guide describes it

Time for each test
Survey of the Natural Sciences 90 minutes, Reading Comprehension 60, Physics 50, Quantitative Reasoning 45.
Break
One optional 30-minute break, after Reading Comprehension.
Aids
A periodic table is shown for the general chemistry questions and a basic on-screen calculator for Quantitative Reasoning.
Retakes
60 days between attempts and at most four in any 12 months. After three attempts, permission to test again is needed.

Checked October 11, 2026 against OAT 2026 Candidate Guide and OAT site, oat.ada.org. Rules change, so confirm with the agency itself before your test.

The official OAT site

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All 55 questions

Biology 12

  • A diploid cell completes meiosis. What does it yield? National Human Genome Research Institute, Talking Glossary of Genomic and Genetic Terms, "Meiosis", glossary entry. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, Biology: Cell and Molecular Biology (mitosis/meiosis).
  • A person with one A allele and one B allele has blood type AB. Which pattern of inheritance does this show? National Human Genome Research Institute, Talking Glossary of Genomic and Genetic Terms, "Codominance", glossary entry and narration. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, Biology: Genetics (classical genetics, human genetics).
  • In which population does genetic drift have its strongest effect? National Human Genome Research Institute, Talking Glossary of Genomic and Genetic Terms, "Genetic Drift", glossary entry. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, Biology: Evolution and Ecology (population genetics).
  • What does an ecosystem's carrying capacity measure? Wikipedia, "Carrying capacity", opening section. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, Biology: Evolution and Ecology (population ecology).
  • What is a plasmid? National Human Genome Research Institute, Talking Glossary of Genomic and Genetic Terms, "Plasmid", glossary entry. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, Biology: Diversity of Life (Eubacteria).
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Biology, continued

  • What is a ribosome made of, and what happens there? National Human Genome Research Institute, Talking Glossary of Genomic and Genetic Terms, "Ribosome", glossary entry. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, Biology: Cell and Molecular Biology (cell structure and function, biomolecules).
  • What is made during transcription? National Human Genome Research Institute, Talking Glossary of Genomic and Genetic Terms, "Transcription", glossary entry. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, Biology: Genetics (molecular genetics, gene expression).
  • Where in the lungs does gas exchange with the blood take place? SEER Training Modules (National Cancer Institute), Anatomy & Physiology, Bronchi, Bronchial Tree, and Lungs, Bronchi and Bronchial Tree. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, Biology: Structure and Function of Systems (respiratory).
  • Which hormones does the adrenal medulla secrete? SEER Training Modules (National Cancer Institute), Anatomy & Physiology, Adrenal Gland, Hormones of the Adrenal Medulla. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, Biology: Structure and Function of Systems (endocrine).
  • Which kind of membrane transport moves ions against their concentration gradient and uses energy, usually from ATP? Kimball, Biology (open textbook on LibreTexts), section 3.23, "Diffusion, Active Transport and Membrane Channels", Transport Across Cell Membranes. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, Biology: Cell and Molecular Biology (cellular processes, membrane transport).
  • Which two structures bend light to focus it on the retina? National Eye Institute, "How the Eyes Work", How the Eyes Work. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, Biology: Structure and Function of Systems (nervous/sensory).
  • Why can a virus not multiply outside a living cell? National Human Genome Research Institute, Talking Glossary of Genomic and Genetic Terms, "Virus", glossary entry. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, Biology: Diversity of Life (viruses).

General chemistry 9

  • 0.50 mol of NaCl is dissolved to make 250 mL of solution. What is the molar concentration? Wikipedia, "Molar concentration", Definition. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, General Chemistry: Solutions (concentration calculations).
  • A gas fills 2.0 L at 300 K. It is heated to 450 K at constant pressure. What is its new volume? Wikipedia, "Charles's law", opening section. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, General Chemistry: Gases (Charles's law).
  • Glucose has the molecular formula C₆H₁₂O₆. What is its empirical formula? Wikipedia, "Empirical formula", opening section and Examples. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, General Chemistry: Stoichiometry and General Concepts (empirical formulae).
  • How does a catalyst speed up a reaction? Wikipedia, "Catalysis", opening section and Catalytic reaction mechanisms. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, General Chemistry: Chemical Kinetics (activation energy).
  • How does electronegativity generally change across the periodic table? Wikipedia, "Electronegativity", Periodic trends. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, General Chemistry: Periodic Properties (periodic trends).
  • In galvanic and electrolytic cells alike, which reaction takes place at the anode? Wikipedia, "Anode", opening section. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, General Chemistry: Oxidation-Reduction Reactions (electrochemical concepts and terminology).
  • Step 1 of a reaction has ΔH = −110 kJ and step 2 has ΔH = −283 kJ. By Hess's law, what is ΔH for the overall reaction? Wikipedia, "Hess's law", opening section. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, General Chemistry: Thermodynamics and Thermochemistry (Hess's law).
  • What is the conjugate base of the ammonium ion, NH₄⁺? Wikipedia, "Conjugate (acid-base theory)", opening section and Acid–base reactions. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, General Chemistry: Acids and Bases (Brønsted-Lowry reactions).
  • Why is the H–O–H angle in water 104.5° and not the 109.5° of a regular tetrahedron? Wikipedia, "VSEPR theory", Degree of repulsion. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, General Chemistry: Atomic and Molecular Structure (molecular geometry).

Organic chemistry 9

  • A Grignard reagent adds to a ketone, and the product is worked up with water. What forms? Wikipedia, "Grignard reaction", opening section and summary box. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, Organic Chemistry: Chemical Synthesis (reactions of ketones and aldehydes).
  • An infrared spectrum of a concentrated sample shows a broad absorption at 3200 to 3400 cm⁻¹. Which group does it point to? Wikipedia, "Infrared spectroscopy correlation table", Group frequencies. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, Organic Chemistry: Chemical & Physical Properties of Molecules (spectroscopy, infrared).
  • An internal alkyne is hydrogenated over a Lindlar catalyst. What is the product? Wikipedia, "Lindlar catalyst", Catalytic properties. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, Organic Chemistry: Chemical Synthesis (reactions of alkenes/alkynes).
  • Chloroacetic acid is a stronger acid than formic acid. What makes it so? Wikipedia, "Inductive effect", Carboxylic acids. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, Organic Chemistry: Acid-Base Chemistry (structure analysis within functional groups, inductive effect).
  • In an E2 elimination, how must the hydrogen and the halogen that leave be arranged? Wikipedia, "Elimination reaction", E2 mechanism and E1 mechanism. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, Organic Chemistry: Mechanisms (elimination).
  • In the free-radical chlorination of methane, what happens in a chain termination step? Wikipedia, "Free-radical halogenation", General mechanism. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, Organic Chemistry: Mechanisms (free radical).
  • In the most stable conformation of methylcyclohexane, where does the methyl group sit? Wikipedia, "Cyclohexane conformation", Monosubstituted cyclohexanes. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, Organic Chemistry: Structural Evaluation (stereochemistry, conformations).
  • What is the hybridization of each carbon in ethylene, C₂H₄, and what are its bond angles? Wikipedia, "Orbital hybridisation", sp2. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, Organic Chemistry: Structural Evaluation (structure and bonding, hybridization, bond angles).
  • Which laboratory technique separates the liquids of a mixture by selective boiling and condensation of the vapors? Wikipedia, "Distillation", opening section. Outline: OAT Candidate Guide 2026, Survey of the Natural Sciences, Organic Chemistry: Chemical & Physical Properties of Molecules (laboratory theory and techniques, distillation).

Physics 13

  • A 2.0 kg cart moving at 3.0 m/s hits a 1.0 kg cart at rest, and they stick together. What is their speed just after the collision? Wikipedia, "Inelastic collision", Perfectly inelastic collision. Outline: OAT Candidate Guide 2026, Physics: Energy and momentum.
  • A 6.0 Ω resistor and a 3.0 Ω resistor are connected in parallel across a 12 V battery. What total current leaves the battery? Wikipedia, "Series and parallel circuits", opening section and Parallel circuits. Outline: OAT Candidate Guide 2026, Physics: D.C. circuits.
  • A 30 kg child sits 2.0 m from the pivot of a seesaw. How far from the pivot must a 20 kg child sit to balance it? Wikipedia, "Lever", Force and levers and Law of the lever. Outline: OAT Candidate Guide 2026, Physics: Statics.
  • A block displaces 2.0 kg of water when it is fully submerged. What buoyant force acts on it? (g = 9.8 m/s²) Wikipedia, "Archimedes' principle", opening section. Outline: OAT Candidate Guide 2026, Physics: Fluid statics.
  • A car rounds a curve of radius 20 m at 10 m/s. What is its centripetal acceleration? Wikipedia, "Centripetal force", Formula. Outline: OAT Candidate Guide 2026, Physics: Rotational motion.
  • A cart starts from rest and accelerates at 2.0 m/s² for 5.0 s. How far does it travel? Wikipedia, "Equations of motion", Constant translational acceleration in a straight line. Outline: OAT Candidate Guide 2026, Physics: Linear kinematics.
  • A net force of 12 N acts on a 4.0 kg block. What is its acceleration? Wikipedia, "Newton's laws of motion", opening section. Outline: OAT Candidate Guide 2026, Physics: Dynamics.
  • A sound wave travels at 340 m/s with a frequency of 170 Hz. What is its wavelength? Wikipedia, "Wavelength", opening section. Outline: OAT Candidate Guide 2026, Physics: Waves.
  • An object stands 20 cm in front of a thin converging lens of focal length 15 cm. How far behind the lens does the image form? Wikipedia, "Lens", Lens equation. Outline: OAT Candidate Guide 2026, Physics: Optics.
  • The distance between two point charges is doubled. What happens to the electrostatic force between them? Wikipedia, "Coulomb's law", opening section. Outline: OAT Candidate Guide 2026, Physics: Electrostatics.
  • How much heat raises the temperature of 2.0 kg of water by 5.0 K? (specific heat capacity of water = 4184 J/(kg·K)) Wikipedia, "Specific heat capacity", opening section. Outline: OAT Candidate Guide 2026, Physics: Thermodynamics and thermal energy.
  • The length of a simple pendulum is made nine times as long. What happens to its period for small swings? Wikipedia, "Pendulum", 1602: Galileo's research. Outline: OAT Candidate Guide 2026, Physics: Simple harmonic motion.
  • Two forces act on a ring at right angles: 3 N east and 4 N north. What is the magnitude of the resultant force? Wikipedia, "Euclidean vector", Length. Outline: OAT Candidate Guide 2026, Physics: Units and vectors.

Quantitative reasoning 12

  • A lens blank is 2.0 inches across. How wide is it in millimeters? (1 inch = 2.54 cm) OAT Candidate Guide 2026 (Optometry Admission Testing Program), Scope of the Examination, Quantitative Reasoning: applied mathematics (word) problems. The answer is worked out from the numbers in the question.
  • A tray holds 5 tinted and 3 clear lenses. Two are picked at random without replacement. What is the probability that both are tinted? OAT Candidate Guide 2026 (Optometry Admission Testing Program), Scope of the Examination, Quantitative Reasoning: probability and statistics. The answer is worked out from the numbers in the question.
  • If x + y = 10 and x − y = 4, what is x? OAT Candidate Guide 2026 (Optometry Admission Testing Program), Scope of the Examination, Quantitative Reasoning: algebra (equations and expressions). The answer is worked out from the numbers in the question.
  • On a map, 1 cm stands for 25 km. Two towns are 7.5 cm apart on the map. How far apart are they? OAT Candidate Guide 2026 (Optometry Admission Testing Program), Scope of the Examination, Quantitative Reasoning: algebra (ratios and proportions). The answer is worked out from the numbers in the question.
  • Quantity A is 2¹⁰. Quantity B is 10³. OAT Candidate Guide 2026 (Optometry Admission Testing Program), Scope of the Examination, Quantitative Reasoning: quantitative comparison. The answer is worked out from the numbers in the question.
  • Solve 3 − x ≥ 7. OAT Candidate Guide 2026 (Optometry Admission Testing Program), Scope of the Examination, Quantitative Reasoning: algebra (inequalities). The answer is worked out from the numbers in the question.
  • Solve 4(x − 3) = x + 9. OAT Candidate Guide 2026 (Optometry Admission Testing Program), Scope of the Examination, Quantitative Reasoning: algebra (equations and expressions). The answer is worked out from the numbers in the question.
  • What is 9 raised to the power 3/2? OAT Candidate Guide 2026 (Optometry Admission Testing Program), Scope of the Examination, Quantitative Reasoning: algebra (exponential notation). The answer is worked out from the numbers in the question.
  • What is the median of 3, 9, 4, 12, 7 and 5? OAT Candidate Guide 2026 (Optometry Admission Testing Program), Scope of the Examination, Quantitative Reasoning: data analysis and interpretation. The answer is worked out from the numbers in the question.
  • What is the value of n? Statement 1: n² = 49. Statement 2: n is negative. OAT Candidate Guide 2026 (Optometry Admission Testing Program), Scope of the Examination, Quantitative Reasoning: data sufficiency. The answer is worked out from the numbers in the question.
  • Where does the line 2x + 3y = 12 cross the y-axis? OAT Candidate Guide 2026 (Optometry Admission Testing Program), Scope of the Examination, Quantitative Reasoning: algebra (graphical analysis). The answer is worked out from the numbers in the question.
  • Which values of x satisfy |x − 4| < 3? OAT Candidate Guide 2026 (Optometry Admission Testing Program), Scope of the Examination, Quantitative Reasoning: algebra (absolute value). The answer is worked out from the numbers in the question.

How this list was compiled: Our own questions, written to the Scope of the Examination in the OAT 2026 Candidate Guide (marked "Updated: 12/15/2025"; linked from https://oat.ada.org/, read 2026-10-11). The guide gives the Survey of the Natural Sciences 100 items (Biology 40, General Chemistry 30, Organic Chemistry 30), Reading Comprehension 50, Physics 40 and Quantitative Reasoning 40. The bank holds 12 biology, 9 general chemistry, 9 organic chemistry, 13 physics (one for each of the 13 physics topics the guide lists) and 12 quantitative reasoning questions, 55 in all. Reading Comprehension (passages) is not in the bank. Organic chemistry follows the guide's list headed "After Update". Every science fact was read on 2026-10-11 in the public source the question names: the Talking Glossary of the National Human Genome Research Institute (genome.gov), the SEER Training Modules of the National Cancer Institute, the National Eye Institute, Kimball's Biology on LibreTexts and Wikipedia. Every number in a calculation was worked out a second time on 2026-10-11. Licence: Own work. Questions and answer choices were written for this site. Explanations restate the public source named under each question, with short quotations in places.

How it works

This free ADA OAT practice test has 55 questions of our own in science, physics and math. It is unofficial and not affiliated with the American Dental Association (ADA) or the Association of Schools and Colleges of Optometry (ASCO).

Read the full guide

What the questions cover

The 2026 OAT Candidate Guide on oat.ada.org (updated December 15, 2025; read October 11, 2026) gives biology 40 questions, general chemistry 30, organic chemistry 30, physics 40 and Quantitative Reasoning 40. This bank holds 12, 9, 9, 13 and 12.

Physics

The guide lists 13 physics topics, from units and vectors to optics. There is one question here on each.

What is left out, and timing

Reading Comprehension needs long passages and is not on this page. Exam mode asks 50 questions in 45 minutes, the pace of the real science test.

  • The real physics test allows 50 minutes for 40 questions: 75 seconds each, a slower pace than the science survey.
  • The guide expects new organic chemistry topic names from June 2026. The organic questions here follow that newer list.

Questions and answers

Is this the ADA's own OAT practice test?

No. The OAT program's own practice test questions are reached through oat.ada.org. The questions on this page are a separate bank, written from the public candidate guide and the public sources they name. None is taken from the real test.

Is there a free ADA OAT practice test?

The OAT site says practice tests are available and points to a tutorial on Prometric's site that shows the test format. The 55 questions on this page are free and need no sign-up.

Why is the OAT on the ADA website?

The Association of Schools and Colleges of Optometry (ASCO) governs the OAT. The Department of Testing Services, a service shared within the American Dental Association, carries it out, and Prometric gives it at its test centers.

How many questions are on the OAT?

230 multiple-choice questions: 100 in the Survey of the Natural Sciences, 50 in Reading Comprehension, 40 in Physics and 40 in Quantitative Reasoning. The sitting runs five hours and five minutes with the optional tutorial, break and survey.

What is a good score on the OAT?

The guide sets no passing score. Scores run from 200 to 400 in 10-point steps, and each optometry program decides what it accepts. A result here is a count of right answers and forecasts nothing.

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