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D2.1.16 (HL)—Mutations in cell cycle genes

Mutations in cell-cycle control genes can activate oncogenes or disable suppressors, causing uncontrolled mitosis and tumour formation in tissues repeatedly.

Syllabus
First assessment 2025
Objective
D2.1.16
Level
HL

Exam analysis

Chance of appearing4%of analysed past papers
Latest appearanceMay 2025
Most common paperPaper2
Typical marks1–4

Common command terms

  • State
  • Outline
  • Explain
  • Predict

Scoring notes

Common mistake
Describing cancer as ordinary growth without linking it to uncontrolled cell division.

Recent exam appearances

May 2025Paper1A ["HL"] · TZ319[ 1 ]D2.1.16 (HL)—Mutations in cell cycle genes
May 2023Paper2 ["HL"] · TZ26(a)[ 4 ]D2.1.16 (HL)—Mutations in cell cycle genes
May 2019Paper1 ["HL"] · TZ23[ 1 ]D2.1.16 (HL)—Mutations in cell cycle genes
May 2019Paper2 ["HL"] · TZ22(a)(ii)[ 2 ]D2.1.16 (HL)—Mutations in cell cycle genes
Practice this objective

Coverage 2019–2025 · Updated 16 Jul 2026

Concept essentials

  • Tumours result from uncontrolled cell division.
  • Oncogene mutations can disrupt cell-cycle regulation.
  • Loss of tumour suppressor function can remove checkpoint control.
  • A high mitotic index can indicate rapid tumour growth.
ConceptIB Biology HL