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D1.2.2—Hydrogen bonding in transcription

Hydrogen bonding allows RNA nucleotides to align with the DNA template during transcription through specific complementary base pairing with exposed bases.

Syllabus
First assessment 2025
Objective
D1.2.2
Level
HL

Exam analysis

Chance of appearing4%of analysed past papers
Latest appearanceMay 2024
Most common paperPaper1
Typical marks1

Common command terms

  • Determine

Scoring notes

Common mistake
Writing thymine in an mRNA sequence instead of uracil.

Recent exam appearances

May 2024Paper1 ["HL"] · TZ128[ 1 ]D1.2.2—Hydrogen bonding in transcription
May 2017Paper1 ["HL"] · TZ19[ 1 ]D1.2.2—Hydrogen bonding in transcription
November 2014Paper1 ["HL"] · TZ030[ 1 ]D1.2.2—Hydrogen bonding in transcription
May 2013Paper1 ["HL"] · TZ17[ 1 ]D1.2.2—Hydrogen bonding in transcription
November 2012Paper1 ["HL"] · TZ027[ 1 ]D1.2.2—Hydrogen bonding in transcription
Practice this objective

Coverage 2012–2024 · Updated 16 Jul 2026

Concept essentials

  • RNA uses uracil instead of thymine during base pairing.
  • The mRNA strand is complementary to the antisense DNA template.
  • The sense DNA strand matches mRNA except for thymine and uracil.
  • Hydrogen bonds align RNA nucleotides before covalent bonds form.
ConceptIB Biology HL