i need help with both please

What is NOT true about PAGE electrophoresis in the presence of SDS? proteins migrate toward the cathode () proteins lose their native conformation and become linear the protein's length becomes roughly proportional to their molecular weight rate of migration is dependent of the molecular size of the protein proteins receive a uniform coat of negatively charged SDS Which of the following is NOT used for the purification of native proteins? ion exchange chromatography dialysis salting out gel filtration SDS PAGE