# Explain how the nuclear pore complex regulates the export of mature mRNA from the nucleus to the cytoplasm as part of the control of gene expression.

> IB DP Biology Higher Level (2023 syllabus) — D2.2 Gene expression (HL only) · Explain · 4 marks

## Mark scheme (4 marks)

1. Mature mRNA must be associated with specific export proteins (mRNA-binding proteins / export receptors such as NXF1) to pass through the nuclear pore complex.
2. Only fully processed (mature) mRNA — with 5′ cap, poly-A tail, and introns removed — is recognised and permitted to exit, so incompletely processed transcripts are retained in the nucleus.
3. The nuclear pore complex acts as a selective channel; the export of mRNA is an active, energy-dependent process (requiring GTP hydrolysis / the Ran-GTP gradient).
4. By controlling which mRNA molecules are exported and when, the cell can regulate which proteins are ultimately translated, providing a post-transcriptional level of gene expression control.

## Key terms

- [nuclear pore complex](https://www.gradenine.co.uk/glossary/nuclear-pore-complex)

## Related

- [Revision notes for IB DP Biology Higher Level (2023 syllabus)](https://www.gradenine.co.uk/learn)
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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-how-the-nuclear-pore-complex-8b28a728) · Published by Druglandscape Ltd.