7.1.1.8 5 9.5 - 7.1.1.8 5.4 9.2 - 7.1.1.8 5.5 9 - 7.1.1.8 6 8 - 7.1.1.8 6.5 9 cytochrome bc1 complex 7.1.1.8 6.5 8 activity increases with increasing pH