Final answer:
Covalent linking of a small organic fluorophore to an antibody in fluorescence microscopy produces a fluorescent antibody that is useful for identifying specific molecules or structures in a cell.
Step-by-step explanation:
Covalent linking of a small organic fluorophore to an antibody in fluorescence microscopy is done to produce a fluorescent antibody.
This fluorescent antibody is useful for identifying specific molecules or structures in a cell. When the fluorophore is attached to the antibody and illuminated with light, it emits visible light of a characteristic color, allowing the target molecule or structure to be detected and studied.