Final answer:
The liposomes likely fluoresce during size-exclusion chromatography because of the fluorescent dyes incorporated into their composition, which emit light at a different wavelength when excited.
Step-by-step explanation:
The fluorescence observed during size-exclusion chromatography of liposomes is most likely due to the presence of fluorescent dyes in the composition of the liposomes. These fluorescent compounds are capable of absorbing light of a specific energy and then emitting light at a lower energy or longer wavelength, known as the emission wavelength. This phenomenon is used in various biological applications to visualize or track the presence of specific molecules or structures.
For example, in fluorescence microscopy, fluorescent tags are attached to antibodies or other molecules that bind to structures of interest within a cell. When exposed to light of the appropriate excitation wavelength, these tags emit fluorescence, revealing the location of the target molecule or structure.