The nucleolus functions primarily to produce ribosomal RNA (rRNA) and assemble ribosomes. It is organized from nucleolar organizing regions (NORs) located on various chromosomes, which come together to transcribe rRNA. The nucleolus contains structures known as pars fibrosa (PF), formed from newly transcribed rRNA, surrounded by electron-dense filaments. Understanding these components is essential for grasping the nucleolus's role in ribosome biogenesis.
PREREQUISITESCell biologists, molecular biologists, and students studying cellular structures and functions will benefit from this discussion on the nucleolus and its role in ribosome production.
The nucleolus is organized from the "nucleolar organizing regions" on different chromosomes. A number of chromosomes get together and transcribe ribosomal RNA at this site. The nuclear organizing (NO) regions are seen as circular areas (pale) surrounded by a rim of electron dense filaments. These filaments collectively are called the pars fibrosa (PF). This is formed from newly transcribed ribosomal RNA. This diagram shows the parts of the nucleolus.