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INTRACELLULAR
RECEPTORS:“LIGAND-ACTIVATED
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TRANSCRIPTION FACTORS”
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HORMONES
WITH INTRACELLULAR RECEPTORS ARE HYDROPHOBIC ALLOWING DIFFUSION
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ACROSS
PLASMA MEMBRANE
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HIGHLY
VARIABLE
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TRANSCRIPTION-ACTIVATION
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DOMAIN
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HIGHLY
CONSERVED (66 AMINO ACID)
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DNA-BINDING
DOMAIN CONTAINING
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TWO
“ZINC FINGERS”
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THIS
PROBLEM IS SOLVED BY UTILISING THE
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ENERGY
OF HORMONE BINDING AT THE CELL
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SURFACE
TO ALTER CONFORMATION OF
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TRANSMEMBRANE
PROTEINS AND THEIR
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INTERACTIONS
WITH INTRACELLULAR
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PROTEINS
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POLYPEPTIDE
HORMONES ARE
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HYDROPHILIC
AND CANNOT DIFFUSE
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ACROSS
THE PLASMA MEMBRANE
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