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A1.2.11 (HL)—Directionality of RNA and DNA

RNA and DNA strands have 5 prime and 3 prime ends, creating directionality that controls strand pairing, synthesis, and reading in IB Biology exam contexts.

Syllabus
First assessment 2025
Objective
A1.2.11
Level
HL

Exam analysis

Chance of appearing2%of analysed past papers
Latest appearanceMay 2025
Most common paperPaper1
Typical marks1

Common command terms

  • Identify
  • State

Recent exam appearances

May 2025Paper2 HL · TZ33(d)[ 1 ]A1.2.11 (HL)—Directionality of RNA and DNA
November 2012Paper1 HL · TZ06[ 1 ]A1.2.11 (HL)—Directionality of RNA and DNA
Practice this objective

Coverage 2012–2025 · Updated 14 Jul 2026

Concept essentials

  • Directionality of RNA and DNA should be described using precise molecular vocabulary.
  • Structure and information must be kept separate: backbones provide continuity while bases carry sequence meaning.
  • Exam answers should match the command term and avoid adding unsupported extra claims.
ConceptIB Biology HL