Final answer:
The statement is true; FRET can be used with both antibodies or fluorescent proteins when the correct excitation and emission wavelengths overlap for efficient energy transfer and visualization of molecular interactions and cell structures.
Step-by-step explanation:
The statement that FRET (Förster Resonance Energy Transfer) can be achieved with both antibodies or fluorescent proteins, provided that the correct excitation and emission wavelengths are selected, is true. FRET is a technique used to study interactions between proteins, DNA, or other molecules within nanometer-range distances by detecting energy transfer from a donor to an acceptor molecule. The energy transfer only occurs when the donor's emission spectrum overlaps with the acceptor's excitation spectrum, requiring careful selection of the excitation and emission wavelengths to facilitate the process.
Additionally, changes in fluorescence, including shifts in wavelengths between excitation and emission as well as differences in intensity, can provide valuable information on molecular environments. For instance, the amino acids tryptophan and tyrosine have characteristic shifts in their fluorescence spectra when they move into different environments, indicating changes in protein conformation.
Fluorescent dyes and proteins enable visualization of various cell structures in fluorescence microscopy by emitting visible light when excited by UV or other forms of light, thus marking the location of target molecules within a cell's structure.