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C2.1.9 (HL)—G protein-coupled receptors

G protein-coupled receptors activate G proteins after ligand binding, linking membrane reception to intracellular second-messenger pathways, linking signal detection to a specific target-cell response.

Syllabus
First assessment 2025
Objective
C2.1.9
Level
HL

Concept essentials

  • GPCRs are membrane receptors linked to intracellular G proteins.
  • Ligand binding changes receptor shape and activates a G protein.
  • Activated G proteins can stimulate production of second messengers such as cAMP.
  • GPCR pathways amplify extracellular signals into intracellular responses.
ConceptIB Biology HL