Pumps - Ion pump

In biochemistry and physiology, ion pumps are transmembrane transport proteins that regulate the transport of certain ions across a biological membrane. The lipid bilayer of biological membranes is impermeable to charged molecules, including ions. Active transport via ion pumps is one of the specific mechanisms that ensure regulated exchange of ions across the membrane or maintain the concentration differences of ions between the two sides of the membrane. In contrast to ion channels, an energetically favorable reaction is coupled with an energetically less favorable reaction.