I know this is going to be a very simple question to ask so I hope to not bore anyone. I am having trouble with redox reactions. Not so much in completing them but in understanding them. The problem that I have is telling when something is reduced or oxidized. I know if it gains electrons, it is reduced and if it loses electrons it is oxidized. I just sometimes don't see it that way. I am working on studying metabolism and it is all redox. Can someone explain how CO is the reduced form of CO2? I see overall why it must be but cannot figure out the electrons for that reaction. It seems that almost all reaction are reduced if something is given off as products. Also, does anyone have any advice on how to tell or remember what is what?