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C2.2.9 (HL)—Action potential propagation

Action potential propagation occurs when depolarized membrane regions trigger adjacent resting regions to open voltage-gated channels, linking cellular mechanisms to rapid communication in nervous systems.

Syllabus
First assessment 2025
Objective
C2.2.9
Level
HL

Exam analysis

Chance of appearing1%of analysed past papers
Latest appearanceNovember 2022
Most common paperPaper2
Typical marks4

Common command terms

  • Explain
  • Describe

Recent exam appearances

November 2022Paper2 ["HL"] · TZ06(b)[ 4 ]C2.2.9 (HL)—Action potential propagation
Practice this objective

Coverage 2022–2022 · Updated 15 Jul 2026

Concept essentials

  • Local current from one depolarized region triggers adjacent membrane.
  • Voltage-gated sodium channels open in the next resting region.
  • Repolarization follows behind the advancing action potential.
  • Propagation is repeated regeneration along the axon membrane.
ConceptIB Biology HL