---
title: IB Biology Question Bank — SL & HL, 2025 Syllabus | FourtyFive
description: An IB Biology question bank covering the current syllabus (first assessment 2025) at SL and HL. All four themes — Unity & Diversity, Form & Function, Interaction & Interdependence, Continuity & Change — across the four levels of organisation, marked mark by mark by our AI Examiner.
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---
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Biology · SL & HL · current syllabus (first exams 2025)
# IB Biology question bank.
Syllabus-mapped IB-style questions across the current Biology syllabus — four themes (A–D) across four levels of organisation (Molecules, Cells, Organisms, Ecosystems), at both SL and HL. Built for the post-2025 Paper 1 + Paper 2 structure.
[Start practising — free](https://fourtyfive.org/join) [Learn more](https://fourtyfive.org/for-students)
Aligned to the current IB syllabus AI Examiner marks mark by mark, IB style Free to start, no card needed
Sample Question · From the bank
Paper 2 Theme D · Genetics HL 5–7
Question 7
In a population of fruit flies (*Drosophila melanogaster*) in Hardy-Weinberg equilibrium, the recessive allele *a* for white eyes occurs at an allele frequency of 0.4.
1. State the conditions required for a population to be in Hardy-Weinberg equilibrium.
\[3 marks\]
2. Calculate the expected genotype frequencies (AA, Aa, aa) in this population.
\[3 marks\]
3. Explain whether the white-eye phenotype would be expected to increase, decrease or remain constant in frequency in this population.
\[3 marks\]
AI Examiner ready Answer →
Syllabus coverage
## Four themes. Four levels of life.
The current IB Biology syllabus is arranged as a 4 × 4 matrix — four themes (A–D) studied across four levels of biological organisation (Molecules, Cells, Organisms, Ecosystems). Every FourtyFive question is mapped to a specific cell of that matrix.
4×4
themes × levels
**SL & HL aligned**
Theme A
Unity &
Diversity
Biochemical foundations, classification, evolution and biodiversity across all four levels.
Theme B
Form &
Function
Structure-function relationships in molecules, cells, organisms and ecosystems.
Theme C
Interaction &
Interdependence
Biochemical reactions, communication, gas exchange, ecology and trophic interactions.
Theme D
Continuity &
Change
DNA replication, mitosis & meiosis, inheritance, populations and evolution.
Practice every paper
## Every paper, weighted like the real exam.
FourtyFive's question bank mirrors the IB assessment model — same paper formats, time limits and weightings you'll meet on exam day.
01
Paper 1
Multiple-choice
\+ data-based.
SL: 1h 30 · 45 marks · 36% · HL: 2h · 60 marks · 36%
Paper 1A is multiple-choice across all four themes; Paper 1B is data-based questions using unfamiliar contexts and graphs. Both sat in one sitting.
02
Paper 2
Data + short answer
\+ extended response.
SL: 1h 30 · 50 marks · 44% · HL: 2h 30 · 80 marks · 44%
Paper 2A is data-based and short answer; Paper 2B is extended response, requiring synthesis across themes. The paper most often decides 6 vs 7.
ia
Internal Assessment
Individual
investigation.
~10 hours · 24 marks · 20% of grade
An open-ended biological investigation written up as a report — the IA rewards a well-defined research question, careful data collection, and honest analysis and evaluation.
Topic · Derivatives Math AA HL
Capability**86**
Fluency**72**
Retention**58**
Confidence**80**
Awareness**66**
Momentum**78**
Mastery — last 7 sessions
Mastery score
76 / 100 +5 this week
Strong recent performance, but retention is fading on chain-rule problems answered \>14 days ago.
Capability · **86** Retention · **58** Confidence · **80**
Why students stick with FourtyFive
## The algorithm earns its keep.
Every answer you submit updates a three-layer mastery score across each topic — proven capability, retention, and confidence. Topics fading from memory get pulled back into your queue before exam season. Topics with sudden drops get flagged for immediate review. You spend revision time where it actually matters.
- Updated after every answer
- Catches sudden drops, not just averages
- Cautious when the data is thin, confident when it isn't
[See how the algorithm works](https://fourtyfive.org/algorithm)
Revision guide
## How to revise IB Biology with a [question bank](https://fourtyfive.org/ib-question-bank).
Biology rewards two things textbooks rarely train you for: precise use of subject vocabulary, and the ability to apply a concept to an unfamiliar context. The new (post-2025) syllabus doubled down on both — Paper 2B is now extended response that explicitly tests synthesis across themes.
FourtyFive's **IB Biology question bank** is built for that loop. Here's how to use it well.
### 1. Drill Theme D early, not last
Theme D (Continuity & Change) covers DNA, inheritance and evolution — content-heavy and easy to leave too late. Rate the syllabus honestly and let [the algorithm](https://fourtyfive.org/algorithm) queue Theme D before you touch the easier ecology questions.
### 2. Use precise IB vocabulary every time
Biology mark schemes are notorious for awarding marks only when specific terminology is used ("differentially permeable" not "semi-permeable", "polynucleotide" not "DNA strand"). The AI Examiner flags imprecise terminology in real time so it becomes habit.
### 3. Treat command terms as instructions
"Outline", "explain", "discuss", "evaluate" — each carries a different mark-scheme expectation. Every FourtyFive question is tagged by command term so you can drill the structure of an answer, not just the content.
### 4. Draw diagrams the IB expects
Labelled diagrams of cells, organs and systems carry marks in their own right. Hand-draw with an Apple Pencil or a USB writing tablet — the AI Examiner reads handwritten labels and marks diagrams to the same standard as typed answers.
### 5. Practise data response on unfamiliar systems
Paper 1B and Paper 2A throw biology you've never seen at you and test whether you can extract a relationship. Drill it as a stand-alone skill, separate from content recall. We tag every data-style question so you can practise the pattern in isolation.
Other IB question banks
## Take a different IB subject?
FourtyFive covers six IB Diploma subjects today, all included on every plan. Cross-link to the rest of the question bank below.
[Mathematics Math AA SL/HL Paper 1·2·3](https://fourtyfive.org/ib-question-bank/math-aa) [Mathematics Math AI SL/HL Paper 1·2·3](https://fourtyfive.org/ib-question-bank/math-ai) [Sciences Physics SL/HL Paper 1·2·3](https://fourtyfive.org/ib-question-bank/physics) [Sciences Chemistry SL/HL Paper 1·2·3](https://fourtyfive.org/ib-question-bank/chemistry) [Humanities Economics SL/HL Paper 1·2·3](https://fourtyfive.org/ib-question-bank/economics)
FAQ
## Questions, answered.
Can't find what you're looking for? [Email our student team](mailto:contact@fourtyfive.org).
How many questions are in the IB Biology question bank?
FourtyFive's Biology question bank covers every theme and level of organisation in the current syllabus at both SL and HL, with thousands of questions tagged by paper, theme, sub-topic and command term.
Is the question bank aligned to the new (post-2025) IB Biology syllabus?
Yes — every question is mapped to the current Biology syllabus (first teaching September 2023, first assessment May 2025). The old Paper 3 and the four options have been retired and the question bank reflects the new Paper 1A/1B and Paper 2A/2B structure built around the 4 themes × 4 levels matrix.
Does FourtyFive cover Paper 2B extended response?
Yes. Paper 2B is extended-response writing that requires synthesis across themes — the highest-leverage part of the new Paper 2. FourtyFive's bank includes dedicated 2B-style essay questions and the AI Examiner marks both content and structure.
Does the AI Examiner mark biological diagrams and labels?
Yes. Hand-drawn diagrams of cells, organ systems, genetic crosses and ecological pyramids are marked alongside typed and handwritten prose. The AI flags missing labels and imprecise terminology the way an IB examiner would.
Can I see worked solutions and a mark scheme breakdown?
Yes. Every question has a step-by-step worked solution plus a per-mark breakdown showing where method credit, content marks and reasoning marks come from, the way an IB-style mark scheme awards them.
Are the questions real IB Biology past papers?
No — the IBO owns the copyright on real past papers and we don't redistribute them. Every question on FourtyFive is original, written in-house to match the style, difficulty and command terms of the exam, and tagged to the current syllabus.
## Start practising IB Biology today. Four themes, four levels, one bank.
Free to start, no card needed. Every theme of the current Biology syllabus, marked mark by mark by our AI Examiner.
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