ion selectivity

Ion selectivity refers to the ability of certain biological or synthetic structures, like channels in cell membranes, to allow specific types of ions (charged particles) to pass through while blocking others. This selectivity is determined by the structure and chemical properties of the channel, which act like specialized filters. For example, a channel might only permit sodium ions because of its size and the arrangement of molecules inside it, preventing potassium or calcium ions from passing. This precise control helps cells maintain proper function, such as sending nerve signals or regulating fluid balance.