IB Biology Paper 3 – Top Tips From the Experts

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IB Biology Paper 3
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IB Biology exam stress? Do not worry! In this blog post, we will explain what IB Biology Paper 3 is, what kind of questions it has, and how you can ace it with some revision and exam tips from our expert IB Teachers and IB Examiners.

You already know that your External Assessment consists of three papers, with the final paper being perhaps the most difficult.

That’s because IB Biology Paper 3 places a heavy emphasis on practical questions, whilst it also features theoretical questions concerning Core and Option topics.

With weights of 20% for SL and 24% for HL, IB Biology Paper 3 can make a big difference in your final grade.

Needless to say, it is vital to have good marks in Paper 3 to secure the grade you hope for. We are here to help you with that.

Note – this article relates to the the syllabus with last examinations in 2024.

What is IB Biology Paper 3?

Above all, Paper 3 is a written exam that tests your conceptual knowledge and the ability to apply it. In addition, it assesses how well you know the material from the Core and Option topics.

Paper 3 consists of two parts: section A and section B.

  • Section A features 2 or 3 short-answer questions related to the experimental work you have carried out during your IB Biology course and linked to the Core material. It awards 10 marks at the SL level and 12 at the HL.
  • Section B focuses on the IB Biology Option topics. You need to choose the topic you’ve studied during your second year and answer the questions related to it. Speaking of questions, there will be several short-answer questions (each worth 1 mark) and one extended-response question, which brings 4 marks at the SL and 6 at the SL. In total, you can earn either 10 or 12 marks depending on your level.

Overall, it takes 1 hour to complete IB Biology Paper 3 at the SL, and the HL students receive 15 minutes more. The total marks are 20 and 24 for the respective levels.

How To Revise for IB Biology Paper 3

It goes without saying that you should pay the utmost attention in class when you’re doing the practicals. The same goes for learning the core and option material. When it comes to revision tips, we can suggest the following:

Review Past Papers

They can help you familiarise yourself with the exam format, questions, as well as the level of detail required. You can find some past papers here and here. When practising with past papers, make sure to note which subject areas you know the least. You should also check the mark schemes and examiner reports to see how your answers are graded and what common mistakes to avoid.

Practice in the Exam Format

When answering past papers, do it under timed conditions. Like this, you will get accustomed to time restrictions and pressure associated with it.

Use Study Tools

It is a good idea to consolidate the core concepts for each topic using your notes, textbooks, and online resources. Pay attention to the details, examples, diagrams, graphs, and tables that illustrate the concepts. To help yourself memorise as much information as possible, you can use flashcards, mind maps, mnemonics, and other study tools.

Know Your Assessment Objectives

Take a look at the IB Biology guide again to learn the assessment objectives for each option topic that you have studied. Not a single key concept, term, or process should come as a surprise in the exam.

Also, make sure you remember all the command terms. They will give you an idea of what you need to do. For instance, the command term ‘outline’ means you need to give a summary of a concept or process, while ‘discuss’ requires a more complex answer with arguments, facts, opinions, etc.

Seek Help

Get feedback from your IB Biology tutor or teacher. They can help you identify your strengths and weaknesses, clarify any doubts, and give you tips on how to improve your answers.

Review all your practicals

Last but definitely not least, you should review all the practicals you have done throughout the course of IB Biology. Make sure you know the aim, method, results, conclusion, and evaluation of each practical. You should also be able to explain the scientific principles behind each practical and how they relate to the topics.

Over the two years of IB Biology, you’ve come across 6 (or 7 if you’re at the HL) types of practicals. Ensure that you know what they are, and that you’re able to repeat them when you sit your exam.

IB Biology practical experiment with plants

The use of a microscope and magnification (Topic 1). To succeed, you need:
  • Know how to calculate the size of an image using a scale as well as calculate the magnification of an image;
  • Be able to outline the Davson-Danielli model and how it was proven false;
  • Give a description of the phospholipid bilayer model;
  • Deduce the stage of mitosis using electron micrographs;
  • Calculate the mitotic index using the data provided.
The osmolarity of tissues (Topic 1). You should be able to:
  • Estimate the osmolarity of an object (usually, a potato) using the data from a graph;
  • Have an understanding of such terms as hypertonic, hypotonic, and isotonic;
  • Predict the changes in an object when it is placed in a hypertonic or hypertonic solution;
  • Know how to control the variables in an osmolarity experiment.
Enzyme activity and the factors that affect it (Topic 2). The main points to focus on are:
  • Deducing and predicting enzyme activity;
  • Which variables need to be kept constant;
  • How to prove a reaction occurred.
Chromatography as a method of separation of photosynthetic pigments (Topic 2). You should be aware of:
  • What the TLC (This Layer Chromatography) is and its benefits over Paper Chromatography;
  • The factors that affect the colour of plants;
  • How to draw an absorption spectrum of chlorophyll and an action spectrum for photosynthesis;
  • The intricacies of the process of photosynthesis.
Mesocosms (Topic 4). You should be able to:
  • Know which variables are needed to be controlled in a mesocosm;
  • Evaluate the use of a mesocosm or evaluate a given mesocosm in a diagram.
Monitoring ventilation in humans (Topic 6). You are required to know:
  • What a spirometer is, how to set it up, and how to use it;
  • What the physiological reasons for changing a breathing rate are;
  • How to calculate the tidal volume and the number of breaths per minute.
Transpiration rates in plants. At the SL, it is not a prescribed experiment, yet you might have conducted it when learning topic 2.8. Cell respiration. Therefore, you need to know:
  • What a respirometer is;
  • How to set it up, how it functions, and which chemicals are used.
At the HL, you’ve learned about transpiration rates at the HL-specific Topic 9. Therefore, you ought to know:
  • What a Potometer is, how to set it up, and the principles of its work;
  • How to evaluate the use of a Potometer and explain the reasons for systematic errors;
  • How to use the Potometer to test for such variables as wind speed, humidity, and temperature;
  • The location of the xylem and phloem in monocot and dicot plants.

Exam Tips to Ace IB Biology Paper 3

So, the D-day has come. You surely have revised and practised a lot. Yet, sometimes minor errors and omissions may prevent you from getting full marks. Here are our tips on what you should and shouldn’t do when sitting your exam.

  • Carefully read the paper instructions and questions. Underline key commands and action words.
  • Note the marks per question and try to organise your time properly. This means you shouldn’t spend too long on one question.
  • Write your responses neatly in the provided boxes. If your answer gets out of the box, something might get missed when your paper is given to a grader for an external assessment. It is better to ask for extra paper if you need more space.
  • Be thorough in your answers. You might use bullet points to provide an extended answer, but you cannot just list key concepts or keywords without a proper explanation. Instead, try to explain your answer the way you would like it to be explained to you.
  • Don’t make your answer too wordy though. With too much said, you might start to contradict yourself or go into unnecessary detail. By contrast, try to write concisely using technical vocabulary.
  • Draw clear, accurately labelled diagrams to illustrate your answers when you think it may be helpful.
  • If you have time, review your work for errors, unclear passages, as well as points you may have missed.

If You Need Extra Help 

IB Biology Paper 3 is the last stage of your external examination, but it doesn’t mean it is the least important. To get the coveted 20 or 24 points (depending on your level), you need to have solid practical skills and knowledge of the core and option IB Biology topics. So, proper revision is a must.

Most importantly, an effective way to prepare for your exam, Paper 3 and not only, is to hire a tutor.

Above all, a tutor can help you with your revision, suggest how to improve your practical skills, provide valuable feedback, and ultimately, give you the confidence you need. To see more of our IB Biology teachers, check out our IB Biology page HERE.

Do you feel like extra support on revising material or developing exam strategies would come in handy? Then don’t hesitate to contact the expert tutors at TutorsPlus at +41 022 731 8148 or info@tutorsplus.com. We assist IB students worldwide in achieving their best on assessment components like Papers 1, 2, and 3. You can also count on us if you need help with your internal assessments, extended essays, and other IB assignments.

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