# 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 Higher Level (2023 syllabus) — A2.2 Cell structure · Explain · 4 marks

## Mark scheme (4 marks)

1. The nuclear envelope consists of two phospholipid bilayers (outer and inner membranes), forming a double membrane that isolates the genetic material from the cytoplasm.
2. Nuclear pores are protein-lined channels that span the double membrane and allow selective transport of molecules between the nucleus and cytoplasm.
3. mRNA and ribosomal subunits are exported through nuclear pores to the cytoplasm, enabling gene expression to occur outside the nucleus.
4. The outer membrane of the nuclear envelope is continuous with the rough endoplasmic reticulum, allowing direct transfer of newly synthesised proteins into the ER lumen for processing.

## 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-08b153fd) · Published by Druglandscape Ltd.