(A) Mitochondrial fission in a COS7 cell yields two daughter mitochondria with a ∼28% difference in TMRE/GFP FI ratio (∼Δ=9 mV). The relative GFP FI change was minimal (Δ=3.4%). For clarity the pseudocolored ratios before fission at 60 and 160 s after fission are shown. Scale bar, 2 μm. 