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D1.2.15 (HL)—Post-transcriptional modification

Post-transcriptional modification converts eukaryotic pre-mRNA into mature mRNA by capping, adding a poly-A tail and splicing introns before translation begins.

Syllabus
First assessment 2025
Objective
D1.2.15
Level
HL

Exam analysis

Chance of appearing6%of analysed past papers
Latest appearanceNovember 2023
Most common paperPaper1
Typical marks1

Scoring notes

Common mistake
Saying introns are added during processing rather than removed.

Recent exam appearances

November 2023Paper1 ["HL"] · TZ223[ 1 ]D1.2.15 (HL)—Post-transcriptional modification
May 2023Paper1 ["HL"] · TZ223[ 1 ]D1.2.15 (HL)—Post-transcriptional modification
May 2022Paper1 ["HL"] · TZ127[ 1 ]D1.2.15 (HL)—Post-transcriptional modification
May 2019Paper1 ["HL"] · TZ127[ 1 ]D1.2.15 (HL)—Post-transcriptional modification
May 2018Paper1 ["HL"] · TZ210[ 1 ]D1.2.15 (HL)—Post-transcriptional modification
Practice this objective

Coverage 2013–2023 · Updated 16 Jul 2026

Concept essentials

  • Eukaryotic pre-mRNA can contain both introns and exons.
  • Splicing removes introns and joins exons.
  • A 5 prime cap and poly-A tail are added during processing.
  • Post-transcriptional modification occurs before translation of mature mRNA.
ConceptIB Biology HL