D1.1.9 (HL)—DNA proofreading
DNA proofreading explains how DNA is copied, checked, amplified or analysed through specific strand relationships, enzyme functions and molecular techniques.
- Syllabus
- First assessment 2025
- Objective
- D1.1.9
- Level
- HL
Exam analysis
Chance of appearing2%of analysed past papers
Latest appearanceNovember 2025
Most common paperPaper1A
Typical marks1–4
Common command terms
- Identify
- Explain
Scoring notes
- Common mistake
- Saying helicase forms new strands instead of unwinding DNA and breaking hydrogen bonds.
Recent exam appearances
November 2025Paper2 ["HL"] · TZ19(a)[ 4 ]D1.1.9 (HL)—DNA proofreading
May 2025Paper1A ["HL"] · TZ19[ 1 ]D1.1.9 (HL)—DNA proofreading
Practice this objective
Coverage 2025–2025 · Updated 16 Jul 2026
Concept essentials
- DNA proofreading depends on matching each strand, enzyme or laboratory step to its exact function.
- Template strands and complementary base pairing give dna proofreading its copying accuracy.
- DNA proofreading is clearer when amplification, separation and profiling are not confused.
- Molecular evidence for dna proofreading must be interpreted from bands, isotopes, primers or enzyme roles.