1- label all lanes, label marker sizes, and indicate which three lanes, containing at least one BSA sample and one E. coli sample, you are writing about.
2- lanes 2, 5, 6, 9, and 11 are BSA, lanes 14 and 15 are empty, and lanes 3, 4, 7, 8, 10, 12, and 13 are E. coli.