Physico-chemical aspects of inorganic element transfer through membranes

For most elements, transfer through a membrane requires combination with a carrier, though some elements diffuse through pores. The carrier is frequently a protein. To understand the movement of the elements through membranes, we need to study the stability and selectivity of binding of elements to proteins, the nature of the proteins within membranes and controls on their concentration. We also need to consider the way in which transport can be made irreversible either by trapping the elements in the cell (no back-reaction) or by energizing the inward transport.