Q BankQuestion BankDocsDocuments

A1.2.13 (HL)—Structure of a nucleosome

A nucleosome consists of DNA wrapped around histone proteins, packaging eukaryotic DNA while still allowing regulated access to genes in IB Biology exam contexts.

Syllabus
First assessment 2025
Objective
A1.2.13
Level
HL

Exam analysis

Chance of appearing11%of analysed past papers
Latest appearanceNovember 2025
Most common paperPaper2
Typical marks1–2

Common command terms

  • Identify
  • State
  • Outline
  • Describe

Scoring notes

Common mistake
Treating a nucleosome as DNA alone instead of a DNA-protein packaging structure.

Recent exam appearances

November 2025Paper1B HL · TZ11(b)[ 3 ]A1.2.13 (HL)—Structure of a nucleosome
May 2025Paper1B HL · TZ12(a)(ii)[ 2 ]A1.2.13 (HL)—Structure of a nucleosome
May 2025Paper1B HL · TZ12(a)(i)[ 1 ]A1.2.13 (HL)—Structure of a nucleosome
May 2025Paper1A HL · TZ32[ 1 ]A1.2.13 (HL)—Structure of a nucleosome
May 2025Paper1A HL · TZ22[ 1 ]A1.2.13 (HL)—Structure of a nucleosome
Practice this objective

Coverage 2012–2025 · Updated 14 Jul 2026

Concept essentials

  • Structure of a nucleosome 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