RNA electrophoresis. Gloved hands of a geneticist with an electrophoresis gel containing RNA (ribo- nucleic acid) molecules extracted from barley (Hordeum sp.). The RNA molecules (white bands) are being observed under ultraviolet light, which causes a chemical present in the gel to fluoresce. The molecules have been separated according to their size, by applying an electrical current to samples loaded onto the gel (electrophoresis). The three bands present in each sample (two bright, one faint) represent different types of RNA. The sample at upper centre contains molecules of known sizes for comparison. RNA is a nucleic acid that functions in the synthesis of proteins.