A Transport Receptor That Moves Macromolecules from the Cytoplasm to the Nucleus

Question

A transport receptor that moves macromolecules from the cytoplasm to the nucleus is called _______.
A)an exhalin
B)an exportin
C)an importin
D)a transportin
E)a receptin

Accepted Answer

Importins are transport receptors that specifically move macromolecules such as proteins and RNA into the nucleus. They recognize nuclear localization signals present on these molecules, bind to them, and then transport them through the nuclear pore complex into the nucleus. Exportins, on the other hand, move macromolecules from the nucleus to the cytoplasm. The other answer choices (exhalin, transportin, and receptin) are not real transport receptors.