What is nuclear-pore complex?

Explanation

**Step-by-Step Solution:**

1. **Definition of Nuclear Pore Complex**: The nuclear pore complex (NPC) is a large protein structure that forms a channel through the nuclear envelope.

2. **Structure**: The NPC is composed of multiple proteins, known as nucleoporins, which create a complex that spans the nuclear envelope.

3. **Function**: The primary function of the nuclear pore complex is to regulate the transport of molecules between the nucleus and the cytoplasm. It allows the passage of ions, small molecules, and larger macromolecules like RNA and proteins.

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