Nucleus: in eukaryotesplugin-autotooltip__default plugin-autotooltip_bigeukaryote: organism whose cells have membrane bound organelles, including the nucleus., the membrane-bound organelle in cells that contains the chromosomesplugin-autotooltip__default plugin-autotooltip_bigChromosome: a structure that organizes dsDNA in a cell through interactions with various DNA binding proteins..