100+ Free IB Biology SL Practice Questions
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Key Facts: IB Biology SL Exam
2025
First exams new syllabus
IB Biology subject guide
150 hours
Recommended teaching time
IB Biology SL guide
20%
Internal Assessment weighting
IB Biology subject guide
100
Free practice questions here
OpenExamPrep
IB Biology SL is assessed via Paper 1 (Part A 30 MCQ + Part B data-based, 90 min) and Paper 2 (data-based, short-answer, extended-response, 90 min) plus an Internal Assessment scientific investigation worth 20%. The new syllabus, first examined in 2025, organises content across four themes and four biological levels of organisation.
Sample IB Biology SL Practice Questions
Try these sample questions to test your IB Biology SL exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.
1Which property of water arises directly from hydrogen bonding between water molecules?
2Cohesion of water molecules is best explained by which interaction?
3Adhesion of water to xylem walls helps transpiration because it
4Why is water described as the universal biological solvent?
5Sweating cools the human body primarily because
6In a DNA double helix, which base pairing is correct?
7Each nucleotide in DNA contains which three components?
8Two antiparallel strands of DNA are held together mainly by
9During transcription in a eukaryotic cell, mRNA is synthesised
10How many bases of mRNA code for one amino acid during translation?
About the IB Biology SL Exam
IB Diploma Biology Standard Level is a Group 4 experimental science course on the new syllabus first examined in May 2025. Content is organised around four themes (Unity and Diversity, Form and Function, Interaction and Interdependence, Continuity and Change), each explored at four levels (molecules, cells, organisms, ecosystems). Assessment combines two written papers with an Internal Assessment scientific investigation.
Questions
100 scored questions
Time Limit
Paper 1: 90 min, Paper 2: 90 min, plus Internal Assessment
Passing Score
Grade 4 commonly used as a pass; grades 1-7 awarded (7 highest)
Exam Fee
School-set entry fee (varies by school and country) (International Baccalaureate Organization (IBO))
IB Biology SL Exam Content Outline
A: Unity and Diversity
Water properties (hydrogen bonding, cohesion, adhesion, solvent, thermal), nucleic acids (DNA double helix, base pairing A-T C-G), gene expression and protein synthesis, mutations, cell theory, eukaryotic vs prokaryotic cells, viruses, classification (domains and kingdoms), binomial nomenclature, cladistics, molecular phylogenetics, biodiversity
B: Form and Function
Organelles (nucleus, mitochondria, chloroplasts, RER, SER, Golgi, 80S vs 70S ribosomes), fluid-mosaic membranes, diffusion and facilitated diffusion, osmosis and water potential, active transport, endocytosis and exocytosis, alveolar gas exchange, ventilation, heart and blood vessels, xylem transpiration and phloem translocation, enzymes (induced fit, denaturation)
C: Interaction and Interdependence
Homeostasis and negative feedback, blood glucose regulation (insulin and glucagon), thermoregulation, neurons and action potentials, synapses and neurotransmitters, endocrine signalling, aerobic respiration in mitochondria and anaerobic respiration (lactate, ethanol), light-dependent reactions in thylakoids and Calvin cycle in stroma, energy flow, carbon and nitrogen cycles, community interactions
D: Continuity and Change
Cell cycle and interphase, mitosis stages (PMAT) and cytokinesis, meiosis vs mitosis, mutation types (substitution, insertion, deletion), Mendelian inheritance and Punnett squares, codominance and sex-linkage, pedigree analysis, discrete vs continuous variation, natural selection and gene-pool change, allopatric vs sympatric speciation, evolutionary evidence, reproduction in animals and plants
How to Pass the IB Biology SL Exam
What You Need to Know
- Passing score: Grade 4 commonly used as a pass; grades 1-7 awarded (7 highest)
- Exam length: 100 questions
- Time limit: Paper 1: 90 min, Paper 2: 90 min, plus Internal Assessment
- Exam fee: School-set entry fee (varies by school and country)
Keys to Passing
- Complete 500+ practice questions
- Score 80%+ consistently before scheduling
- Focus on highest-weighted sections
- Use our AI tutor for tough concepts
IB Biology SL Study Tips from Top Performers
Frequently Asked Questions
When was the new IB Biology syllabus first examined?
The new IB Biology syllabus was first examined in May 2025. It replaces the previous syllabus and is organised around four themes (A-D) explored at four levels of organisation (molecules, cells, organisms, ecosystems).
How is IB Biology SL assessed?
IB Biology SL is assessed by Paper 1 (Part A multiple-choice plus Part B data-based questions, 90 minutes) and Paper 2 (data-based, short-answer and extended-response questions, 90 minutes), together with an Internal Assessment scientific investigation worth 20% of the final grade.
What is the difference between IB Biology SL and HL?
HL covers all SL content plus additional HL-only sub-topics, including more depth on topics such as gene expression regulation, animal physiology and plant biology. HL has longer papers and 240 teaching hours compared with 150 hours at SL.
When are IB Biology exams sat?
IB Diploma exams are held in May (Northern Hemisphere schools) and November (Southern Hemisphere schools). Results are released in early July or early January respectively.