Practice question

STORM leverages reversible photoswitching of bright organic dyes like Cy5-Alexa647 pairs. Under specific buffer containing thiols and oxygen scavengers, dyes stochastically switch between fluorescent and dark states so sparse molecules emit per frame. Centroid localization achieves ~20 nm precision, enabling single-molecule detection and reconstruction of synthetic nanoscale map. Confocal and DIC cannot resolve single molecules below diffraction, and SIM does not isolate individual emitters. Photo-switchable probes provide blinking behavior essential for separating dense labeling, making STORM powerful for dissecting molecular architecture at super-resolution in fixed and live specimens.