A)by protein chaperones that insert polypeptides into the ER membrane
B)by splicing of proteins on either side of the ER membrane
C)via stop- and start-transfer sequences that stop and start translocation of a polypeptide through the ER membrane,resulting in transmembrane proteins
D)by post-translational import can results in a transmembrane ER protein
E)via transit sequences that target polypeptides made in the cytosol for the ER membrane

A)IF3 interaction with an aminoacyl tRNA
B)EF-Tu placement of N-formylmethionine onto the ribosome
C)EF-Tu interaction with an aminoacyl tRNA
D)EF-Ts translocation of tRNAs from the A site to the P site
E)All of these could be potential sites of action.

A)signal recognition particles; activity of proteasomes
B)most proteins; production of lysosomal proteins
C)protein disulfide isomerase; activity of proteasomes
D)most proteins; production of proteins required for protein folding and degradation