Question

Which is FALSE about the ER translocation of proteins?

Both membrane proteins and soluble proteins can be transported into the ER.

Only the correctly folded can be translocated into the ER

ER signal sequence is required to transport proteins into the ER

Signal recognition particle on the ER membrane recognizes the ER signal sequence.

Answer 1

Answer - option c

Because both membrane and soluble proteins can be transported into the ER.ie most of them are made in ER.Second statement is also correct because misfolding causes the polypeptides are exported to the cytosol and delivered to the proteasome for degradation.Statement four is also correct,ie there is a recognition particle or complex named sec61 is present on the ER membrane,which povides a signal peptide recognition site and forms a polypeptide conducting channel.Binding of the incoming polypeptide contributes to the efficiency and unidirectinality of transport.Here it is so clear that no ER signal sequence is required to transport proteins into the ER.