International Baccalaureate. Biology (SL/HL)


A Unity and diversity

A1.1 WaterAnswer (A1.1)

A1.2 Nucleic acidsAnswer (A1.2)

A2.1 Origins of cells (AHL only)Answer (A2.1)

A2.2 Cell structureAnswer (A2.2)

A2.3 Viruses (AHL only)Answer (A2.3)

A3.1 Diversity of organismsAnswer (A3.1)

A3.2 Classification and cladisticsAnswer (A3.2)

A4.1 Evolution and speciationAnswer (A4.1)

A4.2 Conservation of biodiversityAnswer (A4.2)


B Form and function

B1.1 CarbohydratesAnswer (B1.1)

B1.2 ProteinAnswer (B1.2)

B2.1 Membranes and membrane transportAnswer (B2.1)

B2.2 Organelles and compartmentalizationAnswer (B2.2)

B2.3 Cell specializationAnswer (B2.3)

B3.1 Gas exchangeAnswer (B3.1)

B3.2 TransportAnswer (B3.2)

B3.3 Muscle and motilityAnswer (B3.3)

B4.1 Adaptation to environmentAnswer (B4.1)

B4.2 Ecological nicheAnswer (B4.2)



C Interaction and interdependence

C1.1 Enzymes and metabolismAnswer (C1.1)

C1.2 Cell respirationAnswer (C1.2)

C1.3 PhotosynthesisAnswer (C1.3)

C2.1 Chemical signaling (AHL only)Answer (C2.1)

C2.2 Neural signalingAnswer (C2.2)

C3.1 System integrationAnswer (C3.1)

C3.2 Defence against diseaseAnswer (C3.2)

C4.1 Populations and CommunitiesAnswer (C4.1)

C4.2 Transfer of energy and matterAnswer (C4.2)




D Continuity and change

D1.1 DNA ReplicationAnswer (D1.1)

D1.2 Protein synthesisAnswer (D1.2)

D1.3 Mutation and gene editingAnswer (D1.3)

D2.1 Cell and nuclear divisionAnswer(D2.1)

D2.2 Gene expression (AHL only)Answer (D2.2)

D2.3 Water potentialAnswer (D2.3)

D3.1 ReproductionAnswer (D3.1)

D3.2 InheritanceAnswer (D3.2)

D3.3 HomeostasisAnswer (D3.3)

D4.1 Natural selectionAnswer (D4.1)

D4.2 Stability and changeAnswer (D4.2)

D4.3 Climate changeAnswer (D4.3)


Revision questions 

(Revision questions are broadly categorized into 1. Molecules, 2. Cells, 3. Organism and 4. Ecosystem)

Revision Question 1 (4. Ecosystems)

Revision Question 2 (1. Molecules)

Revision Question 3 (4. Ecosystems)

Revision Question 4 (4. Ecosystems)

Revision Question 5 (4. Ecosystems)

Revision Qustion 6 (2. Cells)

Revision Question 7 (1. Molecules)

Revision Question 8 (1. Molecules)

Revision Question 9 (1. Molecules )

Revision Question 10 (2. Cells)

Revision Question 11 (1. Molecules )

Revision Question 12 (1. Molecules)

Revision Question 13 (1. Molecules)

Revision Question 14 (1. Molecules)

Revision Question 15 (1. Molecules)




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