The nuclear pore complex in eukaryotic cells selectively regulates the transport of molecules between the nucleus and the cytoplasm, acting as a gated channel across the nuclear envelope.

What the nuclear pore complex does

  • It spans the double membrane of the nuclear envelope and forms aqueous channels connecting nucleus and cytoplasm.
  • It allows free diffusion of small molecules but controls the passage of large proteins and RNA via receptor-mediated transport.
  • It is essential for processes like mRNA export from the nucleus and import of regulatory proteins (such as transcription factors) into the nucleus.

So, in multiple-choice form, the best statement is the one that says the nuclear pore complex is a selective gateway that controls bidirectional transport of macromolecules between the nucleus and cytoplasm across the nuclear envelope.