I'm a moleculary biology student and have to do a detailed presentation about SDS-PAGE for my next lab.
So I was currently trying to understand the physics of electrophoresis and electrolysis. Since I was never very good at physics I wanted to make sure I understand it correctly:
Am I right in saying, that if I have two electrodes in a non-conducting fluid, that no current will flow and that thus the electrodes are not actually charged but neutral? Since if you have a normal current with a metal wire, current also does not flow, if you have a gap in the wire. The electrones are not "waiting" and the ends of the wire, if you know what I mean.
So the electrodes are uncharged, right? But if I would take salt water as the fluid, the charge can be balanced by ions, and the electrodes themselves will get charged, if we assume that no Redox reaction occurs. So that there is e.g. the cathode with an excess of electrons, and sodium ions moving towards it and then surrounding it. And the more electrons flow over time, the more sodium ions gather there. Am I picturing this correct? But since water is present, electrolysis could occur and the electrons in the cathode would get less (and more in the anode). But why can it still attract proteins and nucleic acids in electrophoresis, if the electrodes are constantly held neutral? Is it because there are constantly electrones flowing and thus the electrodes are never actually neutral? I must say, trying to understand things in detail is very confusing, especially in physics. I hope someone can help and/or maybe recommend a book or other source where this is explained. Most books and videos only explain it superficially and jump right to equations. Thanks :))