Section 3 · Reasoning in Biological and Physical Sciences
GAMSAT Section 3: Reasoning in Biological and Physical Sciences
Seventy-five questions in two and a half hours, worth as much as the other two sections combined. No calculator, no formula sheet, no periodic table — everything a question needs is inside the question.
- 75questions
- 150minutes
- 50%of your overall score
- 2 minper question (arithmetic)
The short version
40% chemistry, 40% biology, 20% physics — and that split is ACER-official, published in the free booklet, not insider knowledge. The section counts double in your overall score. It tests reasoning far more than recall, but not exclusively: ACER says outright that it examines the recall and understanding of basic science concepts too.
What Section 3 is
| Section 3 | |
|---|---|
| ACER’s name for it | Reasoning in Biological and Physical Sciences |
| Questions | 75, multiple choice with four options each |
| Time | 150 minutes |
| Where you sit it | At a test centre, on a supplied computer |
| Weight in your overall score | 50% — it counts double |
| Sat when | Same sitting as Section 1, about three weeks after Section 2 |
The three disciplines are integrated throughout the section, not blocked. You do not get thirty chemistry questions and then thirty biology ones — units are interleaved, so part of what is being tested is your ability to switch subject without losing time.
Because Section 3 counts double, it is worth as much as Section 1 and Section 2put together. That is ACER’s arithmetic, and it is the honest reason to start here rather than a sales argument for a science course.
The subject split is official, not folklore
A lot of preparation marketing implies these proportions are hard-won insider knowledge. They are printed in the free registration booklet.
| Discipline | Share of the section | Questions in a 75-question paper |
|---|---|---|
| Chemistry | 40% | 30 |
| Biology | 40% | 30 |
| Physics | 20% | 15 |
The proportions have not moved in at least six years, so they are safe to plan against. What complicates them is overlap: a question about haemoglobin can be a biology question about cooperative binding or a chemistry question about equilibrium, depending on what it asks. Expect more chemistry-flavoured reasoning than the headline 40% suggests.
Physics is the one most candidates skip. With only 20% of the questions it looks like poor value, but it is also the least-prepared area in the cohort, which makes the marginal return on a few hours there unusually high.
How much science you are assumed to know
ACER’s stated level
The level of subject knowledge required generally corresponds to the first year of university studies in biology and chemistry, and A-level/Leaving Certificate/Year 12 in physics. ACER adds that the section focuses primarily on problem solving and on the use of that prerequisite knowledge.
One well-known preparation site claims the general consensus is that A-level standard is enough for all three subjects. It offers no evidence, and it contradicts ACER’s own wording. Prepare biology and chemistry at first-year undergraduate level.
The opposite error is just as costly. Some published provider syllabuses include material well above ACER’s stated ceiling — named organic reactions, pericyclic chemistry, obscure nomenclature. Treat a maximalist syllabus as evidence of what a course sells, not of what the exam tests. You do not need calculus, quantum mechanics beyond photon energy, relativity beyond E = mc², or detailed gross anatomy.
A non-science degree is not a barrier — ACER says so explicitly — but it also says success will be difficult without genuine ability in the biological and physical sciences. Knowledge is the entry ticket here, not the differentiator. The marks come from applying it to unfamiliar data under time pressure.
Sit a timed Section 3 practice test
Everything above describes the section. This runs it — shared stimulus units, four options a question, a countdown, and a worked explanation for every item once you submit. Nothing is gated and no signup is required.
76 questions available — a full-length sitting, run against the same 150-minute clock as the real section.
Reasoning in Biological and Physical Sciences
- Questions
- 76
- Time limit
- 150 min
- • No calculator, formula sheet or periodic table — as in the real exam.
- • Every constant you need appears in the question’s own material.
- • You can flag questions and return to them before submitting.
- • Scoring happens when you submit. Nothing is saved and no signup is required.
The conditions we replicate
- No calculator, as in the real exam. Every item is solvable by hand.
- No formula sheet and no periodic table.Every constant a question needs appears in that question’s own material.
- Shared stimulus units. Questions attach to a common piece of material in groups, as they do in the real section — not as isolated one-offs.
- All questions carry equal value, which is ACER’s own stated position, and nothing is deducted for a wrong answer.
- Original questions.Nothing here is transcribed from an ACER paper or another provider’s bank — see scope and limitations.
What the questions actually ask you to do
ACER publishes its own list of assessed skills. It is the most useful paragraph in the booklet.
ACER names, among others, the ability to:
- identify knowledge in new contexts, and translate it from one form to another;
- analyse and interpret data, and discover relationships within it;
- formulate and apply hypotheses, and deduce consequences from models;
- follow and evaluate a line of reasoning, and evaluate evidence;
- categorise and select the information relevant to a problem;
- make comparisons, extrapolate, interpolate, estimate, and recognise the limits of accuracy.
The signature move that follows from this is the learn-and-apply item: an unfamiliar rule, formula or reaction is defined in the stimulus, and the questions ask you to use it. You are not expected to have met it before. What you are expected to bring is the reasoning that lets you apply it quickly.
One warning about a claim you will see often: preparation marketing that says Section 3 tests zero recall is overstating ACER’s position. ACER states the section “examines the recall and understanding of basic science concepts”. Recall has a real, if secondary, role.
How the questions are grouped
Questions attach to shared stimulus units — a passage, table, graph, reaction scheme or diagram with questions hanging off it. Reported unit sizes run from 1 to 7 questions, most commonly 2–5, averaging about 4. That works out at roughly 19 units in a full paper — our arithmetic, not an ACER figure. ACER does not publish the number of units.
Stimuli are routinely mixed-medium: prose plus a table plus a figure in one unit. They also carry information you do not need. That is designed in, not sloppiness — selecting the relevant part of an over-supplied stimulus is one of the skills being tested. Practising on tidy, minimal questions trains the wrong reflex.
No calculator, and what that forces
The constraints on the examiner tell you more about the questions than the constraints on you.
| Item | Permitted? |
|---|---|
| Calculator, of any kind | No |
| Formula sheet | No |
| Periodic table | No |
| Ruler | No |
| Scratch paper | Yes — supplied at the test centre |
| Countdown timer | Yes — built into the test application |
Three consequences follow, and they are all useful:
- Every constant a question needs must appear in its own material. Atomic masses, pKa values, standard potentials, spectroscopic shifts — if you need it, it is supplied. Memorising values is wasted effort.
- The arithmetic must be doable by hand in around two minutes. Numbers are chosen so things cancel. If your working is getting ugly, you have probably taken the wrong route.
- No question can require you to measure a figure, because rulers are banned. Anything you need from a graph is readable from its axes.
What you do have to bring is the mathematics itself: log and index laws, rearranging equations, basic trigonometry, scientific notation, reading gradients and areas off a graph, and order-of-magnitude estimation. Formulas beyond the assumed level get supplied; the operations do not.
Marking: every question is worth the same
A correction to the most-cited source in this market
ACER states: "All questions have the same value." Marks are NOT weighted by question difficulty.
GradReady argues that you should attempt the physics questions because marks are allocated by question difficulty, so answers few candidates attempt are worth more. That contradicts ACER directly, and because GradReady is heavily cited in AI-generated summaries the error spreads. ACER does scale raw scores to equate different test forms, but that is not per-question difficulty weighting within your paper. The advice survives; the reason does not.
- No negative marking. Nothing is deducted for a wrong answer, so every question should carry an answer before time runs out.
- Some questions do not count. A live GAMSAT sitting includes unscored trial questions. Neither ACER nor any third party can reproduce an exact scaled score from raw performance.
- Scores are scaled, not raw.The section score is a 0–100 scaled figure and ACER never releases raw marks, so no site — including this one — can convert a practice percentage into a GAMSAT score.
Timing
150 minutes across 75 questions is exactly 2 minutes each, including reading the stimulus. A five-question unit is therefore a ten-minute unit, stimulus included — budgeting per unit rather than per question is what most candidates report working.
The dominant failure mode in this section is not getting questions wrong. It is running out of time and guessing the last stretch. ACER’s own advice is to work steadily, mark an answer even when you are unsure, and come back if there is time.
On reading time
ACER no longer publishes a reading-time breakdown. Earlier booklets (2020–2022) itemised it; the 2026 edition does not.
Two well-known preparation sites still publish an itemised reading period for this section. It was official once. It is not stated now, so we do not print a figure. Plan against the 150-minute total.
What is worth studying, and what is not
Nothing in this part is ACER-sourced — ACER publishes no difficulty or frequency data — so treat it as the consensus of commercial providers with something to sell, corroborated where we could.
Consistently named as high-yieldacross three or more independent providers: data and graph interpretation and experimental design; organic reactions, functional groups and mechanisms; stereochemistry and projections; kinetics and equilibrium; bonding, electronegativity and intermolecular forces; redox and electrochemistry; cell division; and genetics including pedigrees and Hardy–Weinberg.
Consistently named as poor value: memorising the steps of metabolic pathways, specific pKa values or periodic-table data, named reaction recall, botany and ecology terminology, and compiling extensive revision notes instead of working through questions. The rule of thumb providers converge on is to build a broad critical mass and then spend your time applying it.
The single highest-yield skill named by every source is the one that cuts across all three disciplines: reading unfamiliar data and working out what it means. That is what the practice test drills.
Common questions
What is section 3 of the GAMSAT?
Section 3 is Reasoning in Biological and Physical Sciences: 75 multiple-choice questions in 150 minutes, sat at a test centre. It is 40% chemistry, 40% biology and 20% physics by ACER’s own published proportions, and it counts double in the overall score — as much as Sections 1 and 2 combined.
How does GAMSAT Section 3 work?
Questions attach to shared stimulus units — usually 2 to 5 questions on one passage, table, graph or reaction scheme, with the three disciplines interleaved rather than blocked. Each question has four options and asks for the most appropriate answer. No calculator, formula sheet or periodic table is permitted, so any constant or formula a question needs appears in that question’s own material.
Is GAMSAT section 3 hard?
It is the section with the largest body of assumed knowledge — first-year university biology and chemistry, Year 12 physics — and it carries double weight, so mistakes cost the most. It is also the most predictable: the proportions are published, the level has not changed in six years, and the skills ACER assesses are listed in the booklet. Difficulty here is mostly a function of how early you start, which is not true of the other two sections.
Which section of the GAMSAT is the hardest?
ACER publishes no difficulty data. What can be said accurately:
Do you get a periodic table in GAMSAT Section 3?
No — and you do not get a calculator, a formula sheet or a ruler either. Whatever a question needs, including atomic masses and constants, is supplied in that question’s own stimulus. This is the reason memorising values is wasted study time.