One measure of ATP-producing efficiency via oxidative phosphorylation is the P/O ratio, which equals the number of ATP produced per 1/2 O2 consumed (i.e., per electron pair donated into the respiratory chain and passed to the terminal acceptor). To determine the P/O ratio, you must first calculate the number of H+p consumed (i.e., allowed to favorably move down the proton electrochemical gradient) per ATP, which in a mitochondrion will equal: (# of c subunits in F-type ATP synthase + 3)/3. Then, you must divide the number of H+p generated per 1/2 O2 consumed (e.g., 10 for matrix NADH) by that value.
Calculate the P/O ratio for mitochondrial oxidative phosphorylation, given a c11 F-type ATP synthase powered by matrix NADH. Enter your answer (a number only, rounded to the nearest tenth) in the space provided below.