IB Biology 2025 · all 40 subtopics

IB Biology practice questions, by topic.

2,812 original exam-style questions with markschemes, covering every statement in the 2025 guide. Each subtopic page has a ready-made practice paper: teachers can set it as a quiz or homework, students can take it on screen and mark themselves. Print it, project it, or rebuild it in one click. Free, no login.

Full-length mocks

Paper 1 Standard level55 marks · 1 hour 30 minutes
Paper 1 Higher level75 marks · 2 hours
Paper 2 Standard level49 marks · 1 hour 30 minutes
Paper 2 Higher level81 marks · 2 hours 30 minutes

Practice by paper and skill

Paper 1B Standard level4 data-based questions · 25 marks
Paper 1B Higher level4 data-based questions · 35 marks
Extended response by theme102 questions with markschemes
Command terms with marked exampleswhat each one asks for

Theme A · Unity and diversity

A1.1 Water65 questions · SL 20 · HL 20 marks
A1.2 Nucleic acids72 questions · SL 20 · HL 20 marks
A2.1 Origins of cells69 questions · HL only · 22 marks
A2.2 Cell structure69 questions · SL 20 · HL 20 marks
A2.3 Viruses67 questions · HL only · 22 marks
A3.1 Diversity of organisms69 questions · SL 21 · HL 20 marks
A3.2 Classification and cladistics66 questions · HL only · 21 marks
A4.1 Evolution and speciation67 questions · SL 21 · HL 20 marks
A4.2 Conservation of biodiversity65 questions · 20 marks · SL and HL

Theme B · Form and function

B1.1 Carbohydrates and lipids70 questions · 21 marks · SL and HL
B1.2 Proteins70 questions · SL 20 · HL 20 marks
B2.1 Membranes and membrane transport68 questions · SL 22 · HL 20 marks
B2.2 Organelles and compartmentalization70 questions · SL 20 · HL 22 marks
B2.3 Cell specialization71 questions · SL 20 · HL 21 marks
B3.1 Gas exchange70 questions · SL 20 · HL 20 marks
B3.2 Transport75 questions · SL 20 · HL 22 marks
B3.3 Muscle and motility67 questions · HL only · 21 marks
B4.1 Adaptation to environment70 questions · 21 marks · SL and HL
B4.2 Ecological niches67 questions · 21 marks · SL and HL

Theme C · Interaction and interdependence

C1.1 Enzymes and metabolism67 questions · SL 21 · HL 20 marks
C1.2 Cell respiration69 questions · SL 21 · HL 21 marks
C1.3 Photosynthesis68 questions · SL 21 · HL 21 marks
C2.1 Chemical signalling68 questions · HL only · 20 marks
C2.2 Neural signalling67 questions · SL 20 · HL 21 marks
C3.1 Integration of body systems74 questions · SL 21 · HL 21 marks
C3.2 Defence against disease65 questions · 20 marks · SL and HL
C4.1 Populations and communities67 questions · 20 marks · SL and HL
C4.2 Transfers of energy and matter83 questions · 22 marks · SL and HL

Theme D · Continuity and change

D1.1 DNA replication68 questions · SL 22 · HL 20 marks
D1.2 Protein synthesis64 questions · SL 20 · HL 20 marks
D1.3 Mutation and gene editing82 questions · SL 21 · HL 20 marks
D2.1 Cell and nuclear division80 questions · SL 21 · HL 22 marks
D2.2 Gene expression77 questions · HL only · 20 marks
D2.3 Water potential68 questions · SL 20 · HL 20 marks
D3.1 Reproduction70 questions · SL 22 · HL 20 marks
D3.2 Inheritance109 questions · SL 22 · HL 22 marks
D3.3 Homeostasis63 questions · SL 21 · HL 22 marks
D4.1 Natural selection64 questions · SL 22 · HL 20 marks
D4.2 Stability and change66 questions · SL 21 · HL 21 marks
D4.3 Climate change66 questions · SL 20 · HL 21 marks

HL-only subtopics

Every statement in these six subtopics is additional higher level, so they are studied at HL only. Each page has a higher-level practice paper with its markscheme.

A2.1 Origins of cells (HL)69 questions · 22-mark HL paper
A2.3 Viruses (HL)67 questions · 22-mark HL paper
A3.2 Classification and cladistics (HL)66 questions · 21-mark HL paper
B3.3 Muscle and motility (HL)67 questions · 21-mark HL paper
C2.1 Chemical signalling (HL)68 questions · 20-mark HL paper
D2.2 Gene expression (HL)77 questions · 20-mark HL paper

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