Practice question

Dual-color imaging requires fluorophore pairs with well-separated excitation and emission to minimize bleed-through and allow clean channel separation. Alexa 488 excites near 490 nanometers and emits green near 519 nanometers, while Alexa 568 excites near 578 nanometers and emits orange-red near 603 nanometers. Their spectra overlap minimally, enabling distinct laser excitation and filter detection with negligible compensation. This combination supports simultaneous visualization of two antigens, such as tubulin and mitochondria, without FRET artifacts. Pairs with closely overlapping emissions compromise quantification and generate false co-localization signals in merging analysis.