Final answer:
Loading dyes can determine the duration of gel electrophoresis and monitor its progress by providing reference markers that migrate at a known rate.
Step-by-step explanation:
When running a gel, loading dyes can help determine how long to run the gel and monitor its progress. Loading dyes contain markers that migrate through the gel at a known rate, providing a reference for the progress of the gel electrophoresis. For example, bromophenol blue is a commonly used loading dye that migrates through the gel at a predictable rate. By observing the migration of the loading dye, you can estimate how long it will take for your specific samples to reach the desired distance.