A3.1.10—Comparison of genome sizes
Genome size is the total DNA amount in one chromosome set, and it does not reliably measure organism complexity or gene number.
- Syllabus
- First assessment 2025
- Objective
- A3.1.10
- Level
- HL
Exam analysis
Chance of appearing1%of analysed past papers
Latest appearanceMay 2023
Most common paperPaper1
Typical marks1
Common command terms
- Discuss
Scoring notes
- Common mistake
- Equating genome size with gene number or chromosome number.
Recent exam appearances
May 2023Paper1 ["HL"] · TZ112[ 1 ]A3.1.10—Comparison of genome sizes
Practice this objective
Coverage 2023–2023 · Updated 15 Jul 2026
Concept essentials
- Genome size means total DNA amount, not total gene number.
- Genome size can vary greatly between species.
- Large genomes do not necessarily indicate greater organism complexity.
- Claims about genome size and complexity must be evaluated from the data provided.