Here's how it works:
1. Ribosomal RNA (rRNA) genes are transcribed in the nucleolus.
2. Ribosomal proteins are synthesized in the cytoplasm and transported into the nucleolus.
3. rRNA and ribosomal proteins assemble together in the nucleolus to form the two subunits of a ribosome: the small subunit and the large subunit.
4. These subunits are then exported from the nucleus to the cytoplasm where they can join together and participate in protein synthesis.
It's important to note that while ribosomes are assembled in the nucleolus, they are not considered organelles themselves. Instead, they are molecular machines that function within the cytoplasm.
