O2 required to consume 50 nmoles of ADP after mtON activation. Data are the maximum illumination from Fig. EV 4D using time-matched dark conditions, One-way ANOVA *p = 0.013 (-ATR, -light vs. +ATR, +light p = 0.010. -ATR, +light vs. +ATR, +light p = 0.013.) -ATR, -light n = 5, rest n = 6 mitochondrial preparations. Data show mean + SEM. 