Biology / Unit 4 Bio 0775 short lesson, about 20 seconds
Internal Receptors
Captions available
The idea
An internal receptor sits in the cytoplasm and binds a hydrophobic ligand small enough to cross the membrane unaided, often acting on gene expression.
In practice
A steroid hormone diffuses in, binds its receptor, and the complex moves into the nucleus to switch a gene on.
Where people slip
Do not assume this needs a second-messenger cascade — the complex acts on DNA directly, without transduction.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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