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nucleus

(NOO-klee-us)
In biology, the structure in a cell that contains the chromosomes. The nucleus has a membrane around it, and is where RNA is made from the DNA in the chromosomes.
Drawing showing a cell containing organelles, including the nucleus (contains DNA), the nucleolus, Golgi complex, mitochondria, and endoplasmic reticulum. Also shown are the cell membrane and a membrane receptor.Enlarge this image in new window
Parts of a cell. A cell is surrounded by a membrane, which has receptors on the surface. A cell has several small structures inside it, including the nucleus, mitochondria, endoplasmic reticulum, and Golgi complex. These all have specific functions in the cell.
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