Fluorescence is a property of certain fluorophores, which allows them to absorb light at one wavelength and emit the light at another, longer wavelength. This fluorescence can be used as a tool to study the interactions of numerous components within a cell. With the use of fluorescent probes, proteins or other cellular matter can be specifically labeled in a fixed or live cell. This allows scientists to closely monitor microscopic cellular functions in order to gain a greater understanding of living biological processes.
Fluorescence Resonance Energy Transfer (FRET) imaging microscopy is an important and reliable tool for studying minute molecular processes in space and time within a single cell. FRET spectroscopy is a better method for studying the structure and localization of proteins in physiological conditions than are X-ray diffraction, nuclear magnetic resonance, and electron microscopy.