Question 259471

in my teachers book (probably misstranslated from english, and she achieved her doctors degree with this work of copying) she says :

bacteria : the free transportors of electrons (not binded to de membrane) are : nicotine adenine dinucleotide and nicotinamide adenine dinucleotide phosphate, the couples NAD/NADP and NADP/NADPH , and they have a redox potential of -0,320, respectively, -0,324 V

As far as I know NAD is reduce to NAD^+/NADH and NADP is reduced to NADP^+/NADPH

I dont understand what „couples” mean here… and to be fair they are so strangely coupled i dont even believe that this is a correct association

Please, help me learn and not to learn without any logic!

Thank you very much and deeply grateful in advance