Cell Receptor
“Cellular receptors are proteins either inside a cell or on its surface which receive a signal. In normal physiology, this is a chemical signal where a protein-ligand binds a protein receptor. The ligand is a chemical messenger released by one cell to signal either itself or a different cell. The binding results in a cellular effect, which manifests as any number of changes in that cell, including altering gene transcription or translation or changing cell morphology [cell shape].”
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