Cambridge Natural Sciences Interview Questions

Do you have a Cambridge interview coming up? Our list of Cambridge Natural Sciences interview questions contains real questions from past interviews, split by Physical and Biological Sciences, as well as an example question with a detailed worked solution from an Oxbridge interview tutor.

Our advice is that start by reviewing the worked solution first to see the type of thinking admissions tutors want to see from interviewees. Then try some of the questions listed below, particularly focusing on the stream (Physical or Biological) which you’re applying for.

However, we recommend that you use these to practise ways of approaching questions rather than trying to write ‘model’ answers and memorise them. It’s very improbable that you would be asked one of these exact questions in your Cambridge Natural Sciences interview. Even if it were to come up, then Cambridge tutors can tell if you’re reciting a prepared answer and they mark it down.

Sample Interview Question and Worked Solution

Is this disease dominant or recessive?

This Cambridge Natural Sciences interview question is really testing your abilities to think logically, since it doesn’t actually require any scientific knowledge, other than an understanding of basic Mendelian genetics (covered on most GCSE courses). Being able to think logically is a prerequisite of studying science and is therefore often tested at interview. Working through this question helps to illustrate how to structure questions that are not based on pre-existing knowledge, but are instead designed to see how you think.

The key to answering such a question is not to jump in with an answer – it is highly unlikely that you will be given a question like this in an Oxbridge interview if a definitive answer can be reached very quickly. It is also very important to show your interviewer your thought process – including ‘exploratory thoughts’ which may, or may not, prove fruitful. There is no discredit in abandoning an unproductive line of thought; indeed, showing that you have a sense of when it becomes clear that it IS unproductive is just as important as alighting on a productive line of thought straight away.

So where should you begin with a question like this? There are of course a number of different ways of tackling the question. The question is asking whether the disease is dominant or recessive. So an appropriate first stage would be to consider whether the genetic tree diagram makes sense if the disease is dominant; and to do this using a structured method. The first question you would be asking is: does the genetic tree diagram make sense if the disease is dominant? In order to work this out, we must begin by establishing what the different genotypes in the tree will be. Let’s label the dominant allele A and the recessive allele a. If the disease is dominant, normal individuals will therefore have genotype aa. Sufferers on the other hand could have genotype AA or could have genotype Aa. We then begin working through the tree. Again, try pausing here and working from Generation 1 down the tree to see whether it makes sense for the disease to be dominant.

Working through the tree should yield the following conclusions:

• In generation 1 the man is AA/Aa and the woman is aa.
• The offspring in generation 2 are both sufferers. Since they must have received a recessive (a) allele from their mother, and they are sufferers, we know that their exact genotype must be Aa. (At an additional level of analysis we could note that if the man in generation 1 was AA we would have expected 100% Aa in the offspring. If on the other hand the man in generation 1 was Aa we would expect only 50% in the offspring. It is therefore more likely that the first man’s genotype was AA.
• All of the offspring in generation 3 are therefore born from a cross between Aa and aa. We would therefore expect 50% of them to be sufferers. In fact, 100% are sufferers. This is not the most likely outcome from such a cross; but it is still possible that the disease could be dominant.
• The offspring in generation 4 have also all been born from a cross between Aa and aa, which would be expected to give 50% of sufferers. Here, 6 out of 8 of the children are sufferers. This is consistent with the disease being dominant.
• The same again applies to the offspring in generation 5 as to the offspring in generation 4.
• Conclusion: It is possible that the disease is dominant.
• Does the genetic tree diagram make sense if the gene is recessive? Again, it is important to begin by considering what the genotypes would be if the disease were recessive. Sufferers would have genotype aa, whilst non-sufferers could be AA or Aa (carriers).
• In generation 1 the man is aa and the woman is Aa/AA.
• The offspring in generation 2 are both sufferers. The woman in generation 1 therefore MUST have had phenotype Aa in order for the offspring to receive two recessive alleles, and all the offspring in generation 2 have genotype aa.
• The offspring in generation 3 are also all sufferers. The two individuals who marry into the family therefore MUST have had phenotype Aa. (Note that again we would have expected 50% to be sufferers instead of 100%. Therefore the ratios observed are of the same likelihood whether the disease is dominant or recessive and do not help to choose between them.)
• There are sufferers in generation 4. Therefore again the individuals that marry into the family MUST have phenotype Aa.
• There are sufferers in generation 5. Therefore the individuals that marry into the family MUST have phenotype Aa.

Conclusion: It is possible that the disease is recessive: however, this requires making the assumption that every individual marrying into the family is a carrier of the disease. The above would therefore form a well-structured answer to the question posed; though such an answer would often be reached with guidance from the interviewer.

This answer raises the question of how much of an assumption it is to assume that the individuals marrying into the family are carriers of the disease; which creates a more biological aspect to this question. Try and think about whether this is a big assumption to make (and therefore highly unlikely to be valid) before reading the following.

This question requires you to think about why there are carriers present in the population. To decide whether it is a big assumption to make would require some knowledge of the disease. If the disease is very rare and having the gene for the disease is in no way beneficial from an evolutionary perspective then assuming such a prevalence of carriers would be a big assumption to make. However, there are diseases where being a carrier is very beneficial from an evolutionary perspective. The most common example of this is sickle cell anaemia. In sickle cell anaemia, changes in the carriers’ red blood cells means that the malarial parasite cannot complete part of its life cycle. Therefore if someone in a malaria-endemic population is reproducing, it could in fact be argued that it is more likely that they are a carrier, since if they weren’t a carrier they would have had an increased risk of malaria and an increased risk of not reaching child-bearing age.

This illustrates how pre-existing knowledge can be applied to new situations in the science interview questions faced at Oxbridge.

Past Cambridge Natural Sciences Interview Questions

The following questions have appeared in interviews for Natural Sciences at Cambridge in recent years. We recommend that you use these questions to a) familiarise yourself with the types of questions asked and b) practise thinking laterally about your subject.

It’s very inadvisable to try to memorise answers to these specific Cambridge Natural Sciences interview questions. Firstly because the exact questions are very unlikely to recur in your interview, and secondly because Cambridge interviewers can spot prepared answers and do not reward them. They want you to think on your feet and respond to difficult questions in real time, not parrot a script that you learned before the interview.

When you apply for Natural Sciences, you need to specify whether you’re applying for Biological or Physical Sciences. This will affect what questions you’re asked in interview. Don’t worry, though – if you make it to Cambridge, you can choose to study purely biological sciences, purely physical sciences, or a combination of both, and change as you go.  

Natural Sciences (Biological) Interview Questions

• During the war, doctors put jam in people’s wounds. Why?
• Here is a polar bear, a tortoise and a snake. Which is the odd one out and why?
• If you were to engineer a marine organism, what factors would you have to take into consideration and why?
• Why do our shoes have heels? Why might wearing a slight heel be preferable?
• If you had a gene that you needed to transfer into a patient’s cell, how would you go about it?
• Tell me about the influenza virus.
• Draw me the graph of an influenza epidemic.
• Can you think of any substances in our body that are buffers?
• How have plants by the seaside adapted to survive in their environment?
• What do you think has been the greatest contribution to evolutionary biology of Peter and Rosemary Grant’s studies of Darwin’s finches?
• What do you think stimulated the evolution of bodies?
• Regarding his theory of evolution, what evidence did Darwin have at that time and what did he not have, which we now have?
• What is the difference between a frog, monkey and human?
• Discuss the metabolic reactions and enzymes that control body temperature.
• Imagine you have two muscle groups and a group of nerve cells, with a bundle of nerves leaving them and then diverging to synapse onto both muscle groups. Design an experiment to test which muscle the nerve cells project to.
• I was handed a rubbery ball covered in spikes and asked: ‘You’re on Mars. How will you prove that this is alive?’
• What is epigenetics?
• Talk about this twig.
• Talk about the human clock.
• What is contained in the cell nucleus?
• What type of lungs do turtles have?
• How do plants sense gravity?
• Why are saltwater fish unaffected by the high concentration of salt in the water around them?
• What drug would you prescribe to make someone a better marksman?
• How many possible combinations of chromosome pairs are there?

Want more practice? Explore our Oxford Biology interview questions.

Natural Sciences (Physical) Interview Questions

In a Phys NatSci interview, you could be asked questions about Chemistry or Physics.

Chemistry

• Do you know the general formula for a rate equation (rate = k[a]m[b]n)?
• Why does the boiling point of water rise as salt is dissolved in it?
• What do you understand by the term ‘activation energy’? Has it any relation to enthalpy of reaction?
• What makes drugs physiologically active?• What makes drugs physiologically active?
• Questions on isomerisation.
• Write down an organic reaction you have studied at school and explain its mechanism.
• Discuss current issues in chemistry.
• Explain the bonding in benzene.
• Proteins as catalysts – discuss.
• How many atoms are there in a Brussels sprout?
• How do you make aspirin from etanoic anhydride and salycilic acid?
• What makes some chemicals explosive?
• When an ice cube melts in a glass of water, does the water level increase, decrease, or stay the same?

Physics

• How does sound come from a flute?
• How do capacitors add in series?
• Explain how we know a centripetal force exists and how can we prove the presence of this force?
• Which reaches the bottom of a frictionless slope faster: a ball rolling down the slope, or a ball sliding down the slope?
• How would a square wave differ from a sinusoidal wave when applying both to a transformer?
• What is the equation for the motion of a pendulum?
• Draw the equation for the discharge of a capacitor.
• If there are equal resistors on each side of a cube, what is the total resistance from one corner to an opposite corner?
• How does the voltage on a capacitor vary if the dielectric gas is ionised?
• Why is it not strictly true to say that one planet orbits another?
• How is a rainbow formed?
• How does depressing a piano key make a sound?
• What happens if you throw a lead soldier / a ton of gold out of a boat? Does the lake go up or down?

Want more practice? Explore our Oxford Physics and Chemistry interview questions.

How Dukes Plus Can Help

We hope you found practising with these Cambridge Natural Sciences interview questions useful.

If you’d like specialist coaching for your Cambridge interview, our Cambridge interview tutoring includes highly realistic full mock interviews plus feedback from our expert team of Oxbridge-graduate tutors. Some of our packages also include a session with a former admissions tutor at Oxford or Cambridge – someone with direct experience of interviewing candidates for an Oxbridge college.