Electron Transport by Proton Gradients :

Active Transport System :

Electron Transport by Proton Gradients :

Here is Proton Gradients which is also utilizes by Bacteria which is generated during the transport od electrons to drive the active transport mechanism.

Its an electrochemical process which includes an electrochemical gradient is a gradient of electrochemical potential, usually for an ion that can move across a membrane.

The gradient consists of two parts, the chemical gradient, or difference in solute concentration across a membrane, and the electrical gradient, or difference in charge across a membrane. 

When there are unequal concentrations of an ion across a permeable membrane, the ion will move across the membrane from the area of higher concentration to the area of lower concentration through simple diffusion.

ions also carry an electric charge that forms an electric potential across a membrane. If there is an unequal distribution of charges across the membrane, then the difference in electric potential generates a force that drives ion diffusion until the charges are balanced on both sides of the membrane.