Practice question

Polyacrylamide gels are formed by crosslinking acrylamide with N,N'-methylenebisacrylamide, yielding highly uniform pores of 3 to 5 nm diameter depending on total concentration (T%) and crosslinker (C%). This pore size is an order of magnitude smaller than agarose gels, which have pores of 50 to 200 nm. Small pores provide stronger molecular sieving, allowing resolution of DNA differing by single nucleotides in 5 to 500 bp range. Agarose cannot resolve fragments below 50 bp effectively. Thus smaller pore size confers superior resolving power for small nucleic acids.