Biology / Unit 4 Bio 0763 short lesson, about 20 seconds
Ligands and Receptors
Captions available
The idea
A ligand is a signaling molecule released by one cell that binds a specific receptor protein on or in a target cell, the cell the signal affects.
In practice
A hormone circulating in the bloodstream is a ligand; it affects only cells carrying its matching receptor.
Where people slip
A ligand affects only receptor-bearing cells — release does not affect every cell it reaches.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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