a part of the cell containing DNA and RNA and responsible for growth and reproduction any histologically identifiable mass of neural cell bodies in the brain or spinal cord the positively charged dense center of an atom (astronomy) the center of the head of a comet; consists of small solid particles of ice and frozen gas that vaporizes on approaching the sun to form the coma and tail
An organelle of eukaryotic cells that is bounded by a nuclear membrane and contains the chromosomes whose genes control the structure of proteins within the cell
The central controlling body within a living cell, usually a spherical unit enclosed in a membrane and containing genetic codes for maintaining life systems of the organism and for issuing commands for growth and reproduction
a membrane-bounded compartment in an eukaryotic cell which contains the genetic material and the nucleoli The nucleus represents the control center of the cell Nuclei divide by mitosis or meiosis