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B2.2.4 (HL)—Mitochondrion adaptations

Mitochondria are compartmentalized organelles whose cristae, matrix, membranes, and intermembrane space support efficient aerobic respiration and ATP production in cells.

Syllabus
First assessment 2025
Objective
B2.2.4
Level
HL

Exam analysis

Chance of appearing7%of analysed past papers
Latest appearanceNovember 2025
Most common paperPaper1
Typical marks1–2

Common command terms

  • Draw
  • Explain
  • Label
  • Describe
  • Outline
  • Identify

Scoring notes

Common mistake
Naming mitochondrial structures without linking them to respiration or ATP production.

Recent exam appearances

November 2025Paper1A ["HL"] · TZ116[ 1 ]B2.2.4 (HL)—Mitochondrion adaptations
November 2022Paper1 ["HL"] · TZ030[ 1 ]B2.2.4 (HL)—Mitochondrion adaptations
May 2022Paper1 ["HL"] · TZ230[ 1 ]B2.2.4 (HL)—Mitochondrion adaptations
November 2020Paper2 ["HL"] · TZ03(a)[ 2 ]B2.2.4 (HL)—Mitochondrion adaptations
May 2019Paper1 ["HL"] · TZ130[ 1 ]B2.2.4 (HL)—Mitochondrion adaptations
Practice this objective

Coverage 2013–2025 · Updated 15 Jul 2026

Concept essentials

  • Cristae increase inner membrane surface area for electron transport and ATP synthase.
  • The intermembrane space allows proton gradients to build rapidly.
  • The matrix contains enzymes for Krebs cycle reactions.
  • Mitochondria contain DNA and ribosomes for producing some mitochondrial proteins.
ConceptIB Biology HL