IB Biology · current syllabus · first exams 2025 · includes the 2026 update
Every topic,
under one lens.
All 40 topics of the IB Biology course are below. Pick one and you are straight in the lesson: notes written against every syllabus statement, revision slides, and 2,381 exam-style questions, each with a full markscheme.
The syllabus · Standard level view
- Free in full
- HL onlyHigher level only
- Coming soon
AUnity and diversity
Water, nucleic acids, cells, viruses, classification, evolution, conservation.
- A1.1FreeWater
- A1.2Nucleic acids
- A2.1SoonOrigins of cells
- A2.2Cell structure
- A2.3HL onlyViruses
- A3.1Diversity of organisms
- A3.2SoonClassification and cladistics
- A4.1SoonEvolution and speciation
- A4.2Conservation of biodiversity
BForm and function
Molecules, membranes, organelles, specialised cells, gas exchange, transport, adaptation.
CInteraction and interdependence
Enzymes, respiration, photosynthesis, signalling, defence, ecosystems.
DContinuity and change
DNA, protein synthesis, division, inheritance, homeostasis, evolution, climate.
No account needed to start. A1.1 Water and B1.1 Carbohydrates and lipids are free in full, and the revision slides are free on every topic.
Inside every topic
Written statement by statement, straight from the guide.
Each lesson follows the official subject guide in order, with SL and HL marked, so you cover exactly what the exam can ask at your level, and nothing that isn't on it.
- 01Read the notes. Every syllabus statement explained, with labelled diagrams.
- 02Flip the slides. The same topic as an illustrated revision deck, free on every lesson.
- 03Check yourself. Auto-marked questions as you go, each showing why the key is right and which misconception the wrong answers test.
- 04Sit exam-style papers. Paper 1A, 1B and Paper 2 in their real structure and timing, then mark your work against the markscheme.
- 1,739multiple-choice
- 348Paper 1B data questions
- 218Paper 2 items
Data questions are built on real published studies — Gause's Paramecium, Hodgkin and Huxley's squid axon, the Grants' Darwin's finches — so you practise reading the kind of data the exam uses.
- A1.1.1 Water as the medium for life
- A1.1.2 Hydrogen bonds as a consequence of the polar covalent bonds within water molecules
- A1.1.3 Cohesion of water molecules due to hydrogen bonding and consequences for organisms
- A1.1.4 Adhesion of water to materials that are polar or charged and impacts for organisms
Water is described as a polar molecule. What is the underlying reason for this polarity?
- A The two hydrogen atoms repel each other, which bends the molecule
- B Oxygen attracts the shared electrons more strongly than hydrogen
- C Hydrogen bonds form between the H and O atoms inside one molecule
- D Oxygen and hydrogen have equal electronegativity, so sharing is even
For teachers
Build a paper. Hand your class a code.
Pick topics, level and format, or hand-pick questions. Print the paper and its markscheme, or assign it online: students type the code and sit it, multiple choice marks itself, and you mark written answers part by part with comments they can see.
Make a class once and your students join with its code. Then schedule assessments with a date and the topics to revise, even before you build the paper, and start it yourself or at a set time.
Create a free teacher account- Students sit it online with a free account
- See who handed in, scores and time taken
- Real paper formats, marks and timings
Students
- Start free with A1.1 Water and B1.1 Carbohydrates and lipids: notes, quizzes, skills practice and exam papers, all of it
- Revision slides free on every lesson
- Sit a full mixed practice exam drawn from the whole syllabus
- Join your teacher's class and see what's coming up, with the topics to revise
Teachers
- Build a paper from any topics, level and format
- Print it with the markscheme separately, or save it as a PDF
- Assign it to your class and mark it online
- Schedule assessments with dates your students can see