When water and ions move together through channels only a nanometer wide, they behave in unusual ways. In these tight spaces, water molecules line up in single file. This forces ions to shed some of the water molecules that normally surround them, leading to the unique physics of ion transport. Biol ogical channels are especially adept at this behavior, often choreographing channel openings and closings to achieve complex behaviors such as signals in the nervous system. ...read more read less