During gel run, what indicates the procedure is proceeding correctly?

During gel run, what indicates the procedure is proceeding correctly?

• A. The purple loading dye moves toward the negative electrode.
• B. The purple loading dye moves toward the positive electrode.
• C. The purple loading dye stays in the loading well.
• D. The purple dye evaporates.

Answer: (C)

The main idea here is using the colored loading dye to verify that the gel has been prepared correctly and is ready for the run. In this setup, seeing the purple loading dye remain in the loading well indicates that the samples are properly loaded and there are no leaks or premature migrations before you start applying the electric field. It reassures you that the wells are correctly filled and the system is set up to proceed. Once the run actually begins, you would expect the dye to migrate through the gel with the samples, but the initial sign that everything is in place is that the dye stays in the well. The other options describe movement toward electrodes or evaporation, which would signal different, less desirable situations during setup or run.

The main idea here is using the colored loading dye to verify that the gel has been prepared correctly and is ready for the run. In this setup, seeing the purple loading dye remain in the loading well indicates that the samples are properly loaded and there are no leaks or premature migrations before you start applying the electric field. It reassures you that the wells are correctly filled and the system is set up to proceed. Once the run actually begins, you would expect the dye to migrate through the gel with the samples, but the initial sign that everything is in place is that the dye stays in the well. The other options describe movement toward electrodes or evaporation, which would signal different, less desirable situations during setup or run.