Humber Admissions Practice Test

Ribosomes are assembled in the nucleolus, which is a dense region found within the nucleus of eukaryotic cells. The nucleolus plays a critical role in the biogenesis of ribosomes. It synthesizes ribosomal RNA (rRNA) and combines it with proteins to form the subunits of ribosomes. Once these subunits are created, they are exported from the nucleus to the cytoplasm, where they combine to form functional ribosomes that facilitate protein synthesis.

The rough endoplasmic reticulum (ER) is involved in the synthesis and transport of proteins but does not assemble ribosomes. The Golgi apparatus mainly functions in modifying, sorting, and packaging proteins for secretion or delivery to other organelles. The nucleus houses the nucleolus, but it is specifically in the nucleolus that ribosomal assembly occurs, emphasizing its unique and vital role in this process.