# Explain how the structure of the nuclear envelope is related to its function in regulating communication between the nucleus and the cytoplasm.

> IB DP Biology Standard Level (2023 syllabus) — B2.2 Organelles and compartmentalisation · Explain · 4 marks

## Mark scheme (4 marks)

1. The nuclear envelope consists of two phospholipid bilayer membranes (inner and outer), which forms a physical barrier that separates the genetic material from the cytoplasm.
2. Nuclear pores are protein-lined channels in the nuclear envelope that allow selective passage of molecules between the nucleus and cytoplasm.
3. mRNA (and ribosomal subunits) can exit the nucleus through nuclear pores, allowing gene expression to proceed in the cytoplasm.
4. Proteins required in the nucleus (e.g. transcription factors, histones, DNA polymerase) are selectively imported through the nuclear pores from the cytoplasm, enabling regulation of nuclear activity.

## Key terms

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

## Related

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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-how-the-structure-of-the-d36561d1) · Published by Druglandscape Ltd.