Nucleolus

Cell biology
The animal cell
Components of a typical animal cell: Nucleolus Nucleus Ribosome (little dots) Vesicle Rough endoplasmic reticulum Golgi apparatus (or "Golgi body") Cytoskeleton Smooth endoplasmic reticulum Vacuole Cytosol (fluid that contains organelles, comprising the cytoplasm) Lysosome Centrosome Cell membrane

The nucleolus (/njuːˈkliːələs/ or /ˌnjuːkliˈoʊləs/, plural nucleoli /njuːˈkliːəˌlaɪ/ or /ˌnjuːkliˈoʊlaɪ/) is the largest structure in the nucleus of eukaryotic cells, where it is primarily responsible for the creation of ribosomes via a process known as ribosome biogenesis. Nucleoli also have other important functions like assembly of signal recognition particles and playing a role in the cell's response to stress. Nucleoli are made of proteins, DNA and RNA and form around specific chromosomal regions. Malfunction of nucleoli can be the cause of several human conditions which include diseases, disorders, syndromes and illnesses.