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C1.2.11 (HL)—Link reaction

The link reaction oxidizes and decarboxylates pyruvate in the mitochondrial matrix, forming acetyl-CoA for Krebs cycle entry, supporting usable cellular work and measurable biological activity.

Syllabus
First assessment 2025
Objective
C1.2.11
Level
HL

Exam analysis

Chance of appearing8%of analysed past papers
Latest appearanceNovember 2024
Most common paperPaper1
Typical marks1

Common command terms

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Recent exam appearances

November 2024Paper2 ["HL"] · TZ04(c)[ 1 ]C1.2.11 (HL)—Link reaction
May 2022Paper1 ["HL"] · TZ130[ 1 ]C1.2.11 (HL)—Link reaction
May 2021Paper1 ["HL"] · TZ129[ 1 ]C1.2.11 (HL)—Link reaction
November 2019Paper1 ["HL"] · TZ030[ 1 ]C1.2.11 (HL)—Link reaction
May 2018Paper1 ["HL"] · TZ130[ 1 ]C1.2.11 (HL)—Link reaction
Practice this objective

Coverage 2012–2024 · Updated 15 Jul 2026

Concept essentials

  • The link reaction occurs in the mitochondrial matrix.
  • Pyruvate is decarboxylated and oxidized.
  • NAD is reduced during the link reaction.
  • Coenzyme A carries the acetyl group into the Krebs cycle.
ConceptIB Biology HL