IB Biology HL Level External Exams
Quick Study Resources:
External Assessment Components and Weighting (2025 HL Exam)
Paper |
Duration |
Weighting |
Marks |
1 |
2 hours |
36% |
75 |
2 |
2 hours and 30 minutes |
44% |
80 |
External Assessment Grade Boundaries:
Based on May 2025 results
Based on May 2025 results
Paper 1:
Paper 1 is composed of two booklets which are completed together without interruption.
Tips for Paper 1A:
Paper 1 is composed of two booklets which are completed together without interruption.
- Paper 1A (40 marks) - 40 multiple choice questions on standard level (SL) and additional higher level (AHL) material.
- Paper 1B (35 marks) - 4 data based questions related to experimental work and the syllabus.
Tips for Paper 1A:
- Answer every question - there is no penalty for an incorrect answer.
- Read the question carefully. Note important terms.
- Cover the answer choices! Try to answer the question before you read the options. This prevents you from becoming “muddled” with wrong answers.
- Eliminate - Eliminate - Eliminate
- Only change answers if you are ABSOLUTELY SURE the current answer is incorrect. Don’t second guess yourself!
- Avoid patterns (i.e. selecting “C” because there hasn’t been one in a while)
- On the actual exam, you’ll be able to write on the test. Mark it up like crazy!
Paper 2:
Paper 2 has two sections within one booklet.
Tips for Paper 2A:
Rephrase what the question is asking to do... for example:
“Outline the mechanisms used by the ileum epithelial cells to absorb specific food molecules.”
Tips for Paper 2B:
Read the question options carefully and select which you will answer. Your "gut instinct" for which questions to answer might not be the best. Take a few minutes to think of answers to EACH question before selecting the one you feel like you can best respond. Remember, you want to select the question in which you know the most overall about parts A, B and C. Be sure you know what the question is asking. For example, don't answer a question about the speciation process with a response about the limitations of the term species.
Once you have selected which question you will respond to, begin writing an outline to your response to each part. Play attention to the command terms, so you actually address what the question is asking.
Each question includes the maximum number of points possible. As you are drafting your response, predict how points will be awarded on the mark scheme. The general rule of thumb is that the mark scheme used by the assessors will have 1.5X the number of "point earning" ideas as there are points that the question is worth. For example, if a question is worth 5 points, aim for AT LEAST 8 ideas. You will not earn more than 5 points but including extra responses is a good idea (just don't contradict yourself).
Use the following as a guide:
Write your final response using your outline as a guide. Be sure to use legible handwriting that is dark enough to read from a scanned image. If your response is illegible or not visible, you will not earn points.
Paper 2 has two sections within one booklet.
- Section A (48 marks): Data-based questions and short-answer questions on standard level (SL) and additional higher level (AHL) material
- Section B (32 marks): Choice of two out of three extended response questions on standard level (SL) and additional higher level (AHL) material
Tips for Paper 2A:
Rephrase what the question is asking to do... for example:
“Outline the mechanisms used by the ileum epithelial cells to absorb specific food molecules.”
- OUTLINE: give a brief account or summary
- MECHANISMS: processes or functions of
- ILEUM: small intestine
- EPITHELIAL CELLS: cells that line the surface
- ABSORB: take in
- SPECIFIC … MOLECULES: named example molecules
Tips for Paper 2B:
Read the question options carefully and select which you will answer. Your "gut instinct" for which questions to answer might not be the best. Take a few minutes to think of answers to EACH question before selecting the one you feel like you can best respond. Remember, you want to select the question in which you know the most overall about parts A, B and C. Be sure you know what the question is asking. For example, don't answer a question about the speciation process with a response about the limitations of the term species.
Once you have selected which question you will respond to, begin writing an outline to your response to each part. Play attention to the command terms, so you actually address what the question is asking.
- The command term "discuss" is one in which students often mistakenly "explain." When asked to discuss, be sure you address alternative hypothesis and/or give arguments for and against a claim.
- If you are asked to "compare", be sure to include both similarities and differences and to include differences for both items. For example, if asked to compare spermatogenesis and oogenesis, you would not get a point for saying, "spermatogenesis creates 4 sperm." You would get a point for saying, "spermatogenesis creates 4 sperm, whereas oogenesis forms only 1 egg."
Each question includes the maximum number of points possible. As you are drafting your response, predict how points will be awarded on the mark scheme. The general rule of thumb is that the mark scheme used by the assessors will have 1.5X the number of "point earning" ideas as there are points that the question is worth. For example, if a question is worth 5 points, aim for AT LEAST 8 ideas. You will not earn more than 5 points but including extra responses is a good idea (just don't contradict yourself).
Use the following as a guide:
- Define any key terms in the question.
- Where does the process happen? (In what type of cell? In what system? Where in the ecosystem?)
- What happens? What is the outcome of the process?
- How does the process happen? Think of drafting a flow chart to show the process.
- When does the process happen? What triggers the event?
- Why is this process important? What is the reason, purpose, and/or benefit?
- Give an example.
- Draw a labeled diagram.
- Are there any pros/cons? Alternatives? Limitations?
Write your final response using your outline as a guide. Be sure to use legible handwriting that is dark enough to read from a scanned image. If your response is illegible or not visible, you will not earn points.
