It refers to usually 'receptors' that are fixed in a cell, on a cell membrane, and 'ligands' which are dispersed throughout the body and free to diffuse around, and occasionally will find the cell.

受体这个词通常代表了,固定于细胞表面的分子,而配体分散于体内各处,能够自由扩散,它们偶尔会与细胞邂逅

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