Which component assembles ribosomal subunits within a cell?

The nucleolus is the component that assembles ribosomal subunits within a cell. It is found inside the nucleus and is specifically responsible for synthesizing ribosomal RNA (rRNA) and combining it with proteins to form the two subunits of ribosomes—one large and one small. These subunits are essential for protein synthesis, as they translate messenger RNA (mRNA) into proteins.

The role of the nucleolus is crucial to cellular function, as ribosomes are necessary for producing proteins, which are vital for various cellular processes. Once the ribosomal subunits are assembled in the nucleolus, they are then transported out into the cytoplasm where they can join together and function in translation.

Other components, such as the nucleus, the endoplasmic reticulum, and the Golgi apparatus, do have important roles in the cell but are not directly involved in the assembly of ribosomal subunits. The nucleus, while housing the nucleolus and containing genetic material, is not the site of ribosome assembly itself. The endoplasmic reticulum is involved in the synthesis and processing of proteins and lipids but does not assemble ribosomal subunits. The Golgi apparatus is primarily responsible for modifying, sorting, and packaging proteins for secretion or