In molecular biology and biotechnology, fluorescent labels (also known as fluorescent probes) are chemically linked molecules that help detect biomolecules, such as proteins, antibodies or amino acids. In general, fluorescent labeling, uses a fluorophore of a reactive derivative called a fluorescent molecule. The fluorophore selectively binds to a specific region or functional group of the target molecule and can be connected chemically or biologically. Various labeling techniques, such as enzyme markers, protein markers and gene markers, are widely used. Ethidium bromide, fluorescein and green fluorescent protein are common labels. The most commonly used marker molecules are antibodies, proteins, enzymes and peptides, which are then used as specific probes for specific targets.