They are often described as narrow, water-filled tunnels that allow only ions of a certain size and/or charge to pass through.

These proteins sense the change in voltage caused by the nerve impulse reaching their neighborhood, and immediately open up, allowing ions to rush across the membrane.

As the name implies, it separates the positive and negative electrodes while allowing ions to pass through.

Normally the pores open for a millisecond or two, allowing ions to rush in, and then slam shut.

The earthenware barrier was porous, which allowed ions to pass through but kept the solutions from mixing.

As an ion transporter allows ions on the outside to diffuse in, its addition will affect the color/fluorescence property of the dye.

Sea water and fresh water are placed on opposite sides of a membrane that allows ions through, but prevents the passage of water molecules.

By providing greater access to the electrodes, the authors allowed more ions to quickly exchange charge, resulting in a battery with a prodigious charging rate.

One way receptors can react to being bound by a neurotransmitter is to open or close an ion channel, allowing ions to enter or leave the cell.

The membrane allows only positive ions to pass through to prevent the chlorine from mixing with the sodium hydroxide.