Proton pump is an integral membrane protein that is capable of moving protons across a biological membrane. Mechanisms are based on conformational changes of the protein structure or on theQ cycle. In cell respiration, the proton pump uses energy to transport protons from the matrix of the mitochondrion to the inter-membrane space. It is an active pump, that generates a protonconcentration gradient across the inner mitochondrial membrane, because there are more protons outside the matrix than inside. The difference in pH and electric charge (ignoring differences inbuffer capacity) creates an electrochemical potential difference that works similar to that of a battery or energy storing unit for the cell. The process could also be seen as analogous to cycling uphill or charging a battery for later use, as it produces potential energy. The proton pump does not create energy, but forms a gradient that stores energy for later use.