A round, granular structure situated in the nucleus of eucaryotic cells. It is involved in rRNA (ribosomal RNA) synthesis and ribosome formation.
One or more spherical, dark-staining bodies in the nucleus that are rich in RNA and protein.
A structure inside a cell nucleus, containing RNA.
Small structure, composed mostly of ribonucleic acid, found in the nucleus of cells and involved in the formation of ribosomes.
A spherical body inside the cell’s nucleus that participates in the multiplication and metabolism of the cell.
A dense spherical structure within the cell nucleus that disappears during cell division. The nucleolus contains RNA for the synthesis of ribosomes and plays an important part in RNA and protein synthesis.
A spherical structure in the nucleus of a cell made of DNA, RNA, and protein. It is the site of synthesis of ribosomal RNA (rRNA); a cell may have more than one. Embryonic cells and those in malignancies actively synthesize rRNA; therefore, their nucleoli are larger than those of cells that do not require increased amounts of rRNA.