I understand that some bacteria may perform anaerobic respiration as in animal cells by producing lactate from pyruvate and also regenerate NAD from reduced NAD to continue glycolysis. However this surely can't be the only way bacteria cells respire (as far as I'm aware, most of them require oxygen) but how do they do this with no membrane bound organelles and therefore no mitochondria!?

Hi Simon,

Bacteria have a double membrane, and the proton gradients are built up in the periplasm, the space between the membranes. This is exactly what happens in the mitochdrion, and indeed they are believed to have once been free living aerobic bacteria.