EduNinja
Learning objective

A1.2.8—Complementary base pairing

Complementary base pairing links specific bases, allowing DNA replication, transcription, and translation to use predictable molecular matching in cells in IB Biology exam contexts.

Syllabus
First assessment 2025
Objective
A1.2.8
Level
SL

Concept essentials

  • Complementary base pairing 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.

Exam analysis

Question evidence linked specifically to this learning objective.

Chance of appearing2%of analysed past papers
Latest appearanceMay 2018
Most common paperPaper1
Typical marks1

Common command terms

  • Identify
  • Deduce

Exam question appearances

May 2018Paper1 SL · TZ112[ 1 ]A1.2.8—Complementary base pairing
November 2015Paper2 SL · TZ03(c)(iii)[ 1 ]A1.2.8—Complementary base pairing
May 2011Paper1 SL · TZ110[ 1 ]A1.2.8—Complementary base pairing

Coverage 2011–2018 · Updated 14 Jul 2026

Focused stepA1.2.8—Complementary base pairing