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B2.1.14 (HL)—Gated ion channels in neurons

Gated ion channels are selective membrane pores that open or close in response to voltage, neurotransmitters, or mechanical stimuli; Their timing controls membrane potential changes during nervous transmission.

Syllabus
First assessment 2025
Objective
B2.1.14
Level
HL

Exam analysis

Chance of appearing2%of analysed past papers
Latest appearanceNovember 2025
Most common paperPaper2
Typical marks1–3

Common command terms

  • Explain
  • State
  • Identify

Scoring notes

Common mistake
Swapping neurotransmitter-gated acetylcholine receptors with voltage-gated potassium channels.

Recent exam appearances

November 2025Paper1A ["HL"] · TZ115[ 1 ]B2.1.14 (HL)—Gated ion channels in neurons
May 2025Paper2 ["HL"] · TZ23(b)[ 1 ]B2.1.14 (HL)—Gated ion channels in neurons
May 2025Paper2 ["HL"] · TZ23(a)[ 3 ]B2.1.14 (HL)—Gated ion channels in neurons
Practice this objective

Coverage 2025–2025 · Updated 15 Jul 2026

Concept essentials

  • Voltage-gated potassium channels open in response to membrane-potential changes.
  • Potassium efflux through open channels helps repolarize the axon membrane.
  • Neurotransmitter-gated channels respond to ligand binding rather than voltage.
ConceptIB Biology HL