If you have a compound that directly injects a pair of electrons into complex iii of the electron transport chain during aerobic respiration, the number of protons that can accumulate in the intermembrane space as a result of just this electron pair transfer is
a) 6
b)10
c)12
d)112
e)104

A) 6

Explanation:

Complex III of the electron transport chain transfers four protons across the membrane during aerobic respiration, per pair of electrons. In the other hand, complex IV is responsible for transporting two protons (per pair of electrons) across the membrane.

If the given compound injects a pair of electron into complex III,  four protons will accumulated due to complex III activity and then two more protons as these electrons move forward to complex IV. This means a total of 6 protons being transported to intermembrane space.