Hi,
1. Why does H+ leave COOH, but adds to NH2 ? Yes, one is an acid/proton donor, the other a base /proton acceptor (and ok various definitions of acids/bases…Arrhenius/Lewis/Bronsted-Lowry), but what is the reason a given molecule should donate or accept (leaving aside ‘it depends on its environment’). Is it to do with dipoles? Hydrophobicity? Why exactly does COOH tend to kick out the H, yet NH2 tends to take it on?
2. Why does the proton/H+ concentration matter so much (i.e. the pH) is it simply that protons are highly reactive and so run around changing things in a biological system that shouldn’t be changed (or at least shouldn’t be changed at such a high rate). (also I vaguely understand that there are not actually protons on their own but rather hydronium ions and more complicated H5O2, H7O3, etc)
Thanks.
Sean