D1.3.4—Causes of mutation
Mutations arise from replication errors, repair failures or mutagens such as chemicals, ultraviolet light and ionizing radiation damaging DNA in cells.
- Syllabus
- First assessment 2025
- Objective
- D1.3.4
- Level
- HL
Exam analysis
Chance of appearing3%of analysed past papers
Latest appearanceNovember 2025
Most common paperPaper2
Typical marks1–3
Common command terms
- State
- Explain
- Evaluate
- Identify
Scoring notes
- Common mistake
- Giving vague environmental factors without identifying radiation, chemicals or carcinogens.
Recent exam appearances
November 2025Paper2 ["HL"] · TZ15(c)[ 2 ]D1.3.4—Causes of mutation
November 2018Paper2 ["HL"] · TZ01(g)[ 3 ]D1.3.4—Causes of mutation
November 2018Paper2 ["HL"] · TZ01(b)[ 2 ]D1.3.4—Causes of mutation
May 2017Paper2 ["HL"] · TZ25(a)(i)[ 1 ]D1.3.4—Causes of mutation
Practice this objective
Coverage 2017–2025 · Updated 16 Jul 2026
Concept essentials
- Mutagens increase the frequency of DNA sequence changes.
- Radiation, ultraviolet light and some chemicals can cause mutations.
- Smoking can cause cancer because cigarette smoke contains mutagenic chemicals.
- Cancer can result when mutations affect genes controlling cell division.