Agarose Gel Electrophoresis Steps Order

Agarose gel electrophoresis is a method used to separate macromolecules like DNA and RNA based on their size and charge. Understanding the correct sequence of steps is crucial for obtaining accurate results.

Correct Sequence Explained

The process involves several key stages:

1. Preparation of agarose gel (A): This is the foundational step where agarose powder is mixed with a buffer solution, heated to dissolve, and then poured into a mold. A comb is used to create wells in the gel where samples will be loaded. The gel is allowed to solidify.
2. Loading of DNA samples (C): After the gel solidifies and is placed into the electrophoresis tank filled with running buffer, the DNA samples, mixed with loading dye, are carefully loaded into the pre-made wells using a micropipette.
3. Application of electric current (E): An electric field is established across the gel by connecting the electrophoresis apparatus to a power supply. The DNA samples are placed in wells closest to the negative electrode (since DNA is negatively charged).
4. Migration of DNA fragments (D): Driven by the electric field, the negatively charged DNA fragments move through the gel matrix towards the positive electrode. The gel acts as a sieve; smaller DNA fragments navigate the pores more easily and thus migrate faster and further than larger fragments.
5. Visualization under UV light (B): Once the electrophoresis run is complete (indicated by the migration of tracking dyes), the gel is removed and stained with a DNA-intercalating dye. Exposure to UV light allows the visualization of the separated DNA fragments as distinct bands.

Therefore, the correct order for performing agarose gel electrophoresis is A, C, E, D, B.