Here's why:
* Ribosomes are essential for protein synthesis. They are composed of two subunits: a large subunit and a small subunit.
* The nucleolus is a specialized region within the nucleus. It is responsible for the synthesis of ribosomal RNA (rRNA) and the assembly of ribosomes.
* rRNA is a key component of ribosomes. The nucleolus produces rRNA and combines it with ribosomal proteins imported from the cytoplasm.
* The nucleolus brings together the rRNA and proteins to form the two ribosomal subunits. These subunits are then transported out of the nucleus into the cytoplasm, where they can join together to form functional ribosomes.
Therefore, the nucleolus serves as the assembly site for both large and small ribosomal subunits.
