Return to blog

Reasoning in biological and physical sciences

Amongst the medical school aptitude tests, the GAMSAT is often slated as the 'worst' or 'most difficult'. While it can certainly feel like an overwhelming task, and there's often a lot of conflicting information available, there are clear and definable ways to do well in each individual section. There are 3 sections to the exam:

For an in-depth overview of the 3 sections and the administrative components of the exam, you can read our step-by-step guide to GAMSAT.

Section 3 Layout

The third section of the GAMSAT is titled 'reasoning in biological and physical sciences'. It seems like the most obvious and linear thing to put into a medical school aptitude test, people who want to study medicine should have a good grasp of the basics of science, right? Although this feels sensible, a lot of people looking at the GAMSAT questions start to wonder how much of the science is relevant. In a normal educational exam, the questions are based around content that you would have learned as part of a syllabus. The questions are relying on how much of the content you have effectively committed to memory. The GAMSAT questions aren't like this, so people often feel frustrated when they spend hours committing content to memory and still struggle with the questions.

The GAMSAT S3 is a much more cognitive skills-based examination, more like an IQ test than a traditional content exam. Although some scientific knowledge is required to understand and contextualise the questions, you will be asked to problem solve and follow a line of reasoning to come up with answers instead of being directly asked "define mitochondrial DNA" for 3 marks. This difference in the style of questions should be reflect in how you prepare for the exam, and what you revise!

Section 3 consists of 75 multiple choice questions (MCQs) in 150 minutes, this works out as roughly 2 minutes per question. As with Section 1, you'll find some questions quicker than others. A good rule of thumb is the 4-minute mark. If you're really stumped by a question and have put 4 minutes into it, it's probably your best bet to guess and move on otherwise you could be sacrificing questions at the end of the paper that you won't have time to read.

Also like Section 1, the questions are split into 'stems' which are this time various forms of written or numerical information that are focussed on a science theme. They can be paragraphs, diagrams, extracts from studies, graphs, organic chemistry diagrams or tables of results. Each stem is associated with one or more questions. You are required to use more of your own knowledge to answer the questions than in Section 1, but a lot of the information you require is right there in the stem if you interpret it accurately.

Timing and Test Strategy

Section 3 can feel tight for time, but most likely less than the previous 2 sections. Despite this, it's important to keep your head in the heat of the exam and not front-load the early questions with all your precious time, leaving you struggling at the end of the paper. If you feel like you aren't making headway with a question set, you can always guess and move on and come back to them at the end.

It's important to read the stem before you look at the questions, as this will provide you with the appropriate context to start thinking about which skills are relevant. Don't be fooled by extra information or leading language used in the questions – just because it's taking about blood in arteries doesn't mean it's a biology question, is it actually asking you to calculate acceleration that would be based around a physics formula?

The fact the test is multiple choice can be used to your advantage as well, it helps when it comes to calculations as if there are large differences in integer between the answer options you can be generous with rounding up and rounding down. If you try to figure out the answer to the question before you look at the answer options, it means if what you thought it was is there, you can pick it and move on. If it's not there then you know you're on the wrong track and you might need to try another approach.

Revision and Resources

It can feel frustrating to be left without a topic list when it comes to revision, but the one thing ACER provide for you is practice questions. In a normal content exam, you would look at the syllabus, memorise the content based on that, and then take the test. I would advise doing it the other way around, look at the practice exams and questions available to you and think about what you would need to know to get the questions right. Are there common themes that you see such as acids and bases, organic chemistry, graph interpretation. Then you can target these areas in your revision and do reading and further question practice around them. That way you are targeting your revision as much as possible instead of aimlessly memorising as much science as you can, with no real guide or benefit.

Although ACER quotes 'first year undergraduate' chemistry and biology, A-level textbooks are an excellent resource for all 3 of the sciences. The content tested in the exam doesn't go much beyond this, but the higher reasoning skills such as the problem solving and critical analysis reflect a first-year undergraduate. Textbooks can really help provide some structure to your revision but remember not to just read it cover to cover and target your revision as much as possible based on what you've gleaned from the practice questions!

Other useful resources include YouTube videos and revision websites that are geared towards GAMSAT specifically or more general A-level science. I would always make sure to supplement these with reading from a textbook and question practice. Similarly, to Section 1, it is advisable to start with untimed question practice first in order to learn the style of questions and the skills required to answer them. Adding in a scaled timing increase from twice the amount of time you'd have in the exam, to time and a half, to time and a quarter, and eventually in the same time you'd have in the exam is the most beneficial way of training up to timed questions.


The paper is touted as being 40% Biology, 40% chemistry and 20% physics. In a content-based exam it might seem like a good idea to ignore the physics and memorise more of the other content, but as we've discussed memorisation of content doesn't help with this paper. It's also quite difficult to predict which skills the questions will require from you, there's no guarantee that if you've spent 12 hours on organic chem you are definitely going to get all those questions right. However, if you spend at least some time on the physics you are in with a chance of attempting these, as opposed to total guesswork.

Do to the fact you aren't given access to a calculator, it's essential to practice mental maths or maths that can be done with a pen and paper (like long division). Identifying a quick and simple way to solve a problem using maths is key, as well as being familiar with some key equations such as Force = mass x gravity, or moles = mass / RMM.

The final thing that most people don't realise is what a large part maths plays in the paper. Looking at the practice papers, you can see that throughout section 3 if you don't have strong maths skills you will really struggle, irrespective of how much science you know. Look at maths topics such as logarithmic skills, trigonometry and being comfortable with rearranging and substituting into equations are all key skills for Section 3 and students will benefit enormously in terms of marks if they are comfortable with these things and build them into their revision process.

Example Question

Unit 2

Power can be defined as the amount of energy transferred or converted per unit of time, signified by the SI unit watts. Due to the fact that power has only magnitude, it is defined as a scalar vector. Other common and traditional measures are horsepower (hp), comparing to the power of a horse; one mechanical horsepower equals about 745.7 watts.

5 If a horse is used to pull a plough for 20 minutes around a field, and it utilises 1200 joules of work to do so, what is its power?

A 1 watt

B 600 watts

C 60 watts

D 12 watts

6 If a car is described as having 35,000 horsepower, what will the equivalency in watts be if the car is travelling as fast as possible in reverse?

A 0.26 x 10-4

B 0.26 x 108

C 0.26 x 104

D 0.26 x 10-8

  1. Answer = A

An equation is useful here, although it can be inferred from the text itself that power is energy used over time taken. The equation is Power (watts) = energy (j) / time (s). We are told the horse uses 1200 joules. 20 minutes is 1200 seconds so 1200/1200 is 1 watt.

  1. Answer = B

We are given the information we need for this question in the stem as we are told that 1 horsepower is equal to 745.7 watts. For ease of calculation I would round this to 750. If we multiply 35 by 7 we would get around 245 so if we're multiplying 35,000 by 750 we will get around 24 500 000. The final part of the question is being comfortable with scientific notation. The reverse is there as a red herring to think the number must be negative, but power can't be a negative number as it is a scalar vector!


In summary, S3 questions are often less about rote-memorisation of science content and more about problem solving and critical analysis. Making sure to look at ACER papers before beginning your revision can help you to target areas of key understanding, making use of a structured tool like a textbook can keep you on track, and it's really important to be comfortable with maths before attempting the paper as it forms a larger part of the questions than most candidates realise.

Further information and support can be found within FutureDoc's GAMSAT course as part of our 1-1 mentoring programme, written and delivered by graduate entry medical students who all secured places after succeeding in their GAMSAT.

Written by Charlie Bailie