A molecular-weight size marker, also referred to as a protein ladder, DNA ladder, or RNA ladder, is a set of standards that are used to identify the approximate size of a molecule run on a gel during electrophoresis, using the principle that molecular weight is inversely proportional to migration rate through a gel
Hereof, why do we add the loading buffer to the DNA?
Ethidium bromide is a molecule commonly used to visualize DNA in agarose gel electrophoresis experiments. It intercalates between the nitrogenous bases of DNA and fluoresces under UV light. Loading buffer is a solution added to an electrophoresis sample to give it color and density.
What is the loading buffer for?
Loading dye is mixed with DNA samples for use in agarose gel electrophoresis. It generally contains a dye to assess how "fast" your gel is running and a reagent to render your samples denser than the running buffer (so that the samples sink in the well).
What is a Laemmli buffer used for?
Laemmli sample buffer is especially formulated for protein sample preparation to be used in the Laemmli SDS-PAGE system. A protein sample is mixed with the 2X sample buffer (1:1) and heated in boiling water for 2-5 min. The 2-mercaptoethanol reduces the intra and inter-molecular disulfide bonds.