A Unity and diversity
Molecules
IB Diploma Biology · first assessment 2025 · SL & HL
See the biology, then test yourself
Rotate a 3D membrane, step through the sodium–potassium pump, drag sliders to see what really changes a rate. Every topic has clear explanations with SL and AHL content marked, common exam mistakes, and a self-test that remembers your progress.
What's on each topic page
- Interactive visuals 3D models you can rotate and label, step-by-step animations and simulations with live graphs, plus exam-style diagrams.
- SL vs AHL clearly marked Higher Level content sits in purple AHL sections; SL students can hide it in Display settings.
- Self-test Multiple-choice questions with an explanation for every option, and flashcards. Progress is saved in your browser only.
The syllabus
The course is organised into four themes, each studied at four levels of biological organisation.