A nucleolus is a substructure composed of nucleic acids and proteins that is found within the nucleus of a cell. Known as the ribosome production factory, malfunction of the nucleolus has been found to cause disease in humans.
A nucleolus is a non-membranous structure found within a cell's nucleus. It is composed of proteins and nucleic acids and is the site of rRNA (ribosomal ribonucleic acid) assembly and transcription. Nucleoli have three essential components: the fibrillar centers, the dense fibrillar components and the granular component; all of which aid in the transcription and assembly of ribosomes and RNA. Plant nucleoli have a different structure called a vacuole.
Due to its important role in ribosome production and genetic transcription, mutation or malfunction inside a nucleolus can lead to the development of disease as observed in the testing field.