Question

which protein would you expect to find closer to the wells where the sample was loaded: a protein with a molecular weight of 10,000 Da or a 75,000 Da protein?

Answer 1

The protein with 75 000 Da will be found closer to the wells.
the mobility of proteins in the gel depends on their mass.
mobility is inversely proportional to the mass of proteins.
lower the molecular weight of the protein higher its mobility in the gel. when the samples are loaded in to the wells, the protein with lesser molecular weight will travel a longer distance than the higher molecular weight proteins.
the molecular weights of proteins are measured in Daltons (Da) that are equivalent to atomic mass units,in other words 1 Da is 1/12th the mass of a carbon atom.
proteins are made of amino acid, an average amino acid has a weight of 135 Da, the given proteins weigh 75 000 Da and 10 000 Da. Therefore 75 000 Da protein has a higher molecular weight therefore 10 000 Da protein will travel further than 75 000 Da, it will be found closer to the wells