I always thought that atoms and molecules tend to hold no charge unless some force is involved.
I'm learning about the electron transport chain in particular, and about redox reactions in general, and it seems that there are continual changes in positive and negative charges. Is there something powering all of these changes in charge, or am I mis-remembering the thing about atoms and molecules wanting to remain neutral? I understand that if the molecules are polar, the water molecules in the cytosol could pull them apart, resulting in charges, but what would cause them to continually gain and lose electrons, as in the case of NAD+ being transformed to NADP and then back to NAD+ again, continually? My biology textbook says that NAD+ gains an H and an electron from another H. Why doesn't NAD+ just gain two Hs and become NADH2+? What is powering the separation of the H electron from its proton?
I read something about electron flow and batteries, where the electrons sort of move around freely, but I don't understand what would cause that to happen in a cell. Help?
