NUCLEUS (KARYON) (plural – Nuclei)
Discovery: Robert Brown (1831) – discovered in the cells of orchids
Nucleus is a darkly stainable, largest cell organelle present in eukaryotic cells. It is usuallyspherical. It may be lobed in WBC, kidney shaped in paramecium.
Nucleus has an outer double layered nuclear membrane with nuclear pores, a transparent granular matrix called nucleoplasm or karyolymph, chromatin network composed of DNA and histones and a darkly stainable spherical body called Nucleolus.