(couleur) grey (Grande-Bretagne) , gray (USA) il fait gris it's a dull day, it's a grey day. faire grise mine to look morose. faire grise mine Ã  qn to give sb a cool reception.
In electrophilic aromatic substitution, the benzene ring acts as an electron donor (Lewis base or nucleophile) and reacts with an electron acceptor (Lewis acid or electrophile). The result of electrophilic aromatic substitution reactions is that an aromatic hydrogen is replaced by some other atom or functional group.
Here's a shorter answer. electron transport chain pumps hydrogen ions out of the the mitochondial matrix. hydrogen ions are H+. If you look at the periodic table, hydrogen has 1 proton and 1 electron. An H+ ion is missing an electron, which makes it basically a proton. Since there are a lot of protons pumped out of the matrix, this creates too many h+ ions in the intermembrane space, creating a proton gradient.