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
- SL
Exam analysis
Chance of appearing3%of analysed past papers
Latest appearanceNovember 2025
Most common paperPaper1B
Typical marks1
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 2025Paper1B ["SL"] · TZ14(d)(ii)[ 1 ]D1.3.4—Causes of mutation
November 2025Paper1B ["SL"] · TZ14(d)(i)[ 1 ]D1.3.4—Causes of mutation
November 2025Paper1B ["SL"] · TZ14(b)[ 1 ]D1.3.4—Causes of mutation
November 2024Paper1 ["SL"] · TZ215[ 1 ]D1.3.4—Causes of mutation
May 2019Paper2 ["SL"] · TZ24(b)[ 2 ]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.