Practice question

ANEP dyes are aminonaphthylethenylpyridinium potentiometric probes exhibiting voltage-dependent shifts in excitation and emission spectra. Mitochondria maintain a strong interior-negative potential near -150 to -180 mV generated by proton pumping of respiratory complexes. Lipophilic cationic ANEP molecules partition into energized inner membranes in a potential-dependent manner, providing fast ratiometric optical readout of depolarization during calcium overload, permeability transition, apoptotic signaling or uncoupling. Unlike fluorescein which reports pH and DAPI which binds AT-rich nuclear DNA, ANEP indicators directly sense mitochondrial electrical energetics.