Process
Transcription
Copying the DNA sequence of a gene into RNA.
Nucleus
Stores most of the cell's DNA and controls which genes are used.Source: NHGRISource: Alberts et al., 2002Source: Cooper, 2000
Step 3 of 7ReadingStructure
Inside the cell: nucleus
The nucleus is the cell's control room. It holds most of the cell's DNA, the instructions for building and running the cell.
The nucleus stores the chromosomes and is where DNA is copied and genes are transcribed into RNA. A double membrane called the nuclear envelope separates it from the rest of the cell, and nuclear pores control what moves in and out.
The nuclear envelope is a double membrane continuous with the endoplasmic reticulum and perforated by nuclear pore complexes, which control the import of proteins and the export of RNA. Inside, chromatin is packaged with histones, and the nucleolus assembles ribosomal subunits. A meshwork of lamin proteins lines and supports the envelope.
- Structure
Double membrane (nuclear envelope) with pores, chromatin (DNA wrapped around proteins), a dense nucleolus, and a supporting layer of lamin proteins.
- Key molecules
- DNA
- Histones
- RNA polymerase
- Lamins
- Nuclear pore proteins
Related health conditions
- Hutchinson-Gilford progeria syndrome. Caused by variants in the LMNA gene. Lamin A normally helps shape the nucleus and supports the nuclear envelope; an abnormal version makes the envelope unstable and damages the nucleus over time.Source: MedlinePlus
For learning only, not medical advice.
How Nucleus connects
Nucleus is the site of
Nucleus is part of
Level of life
Cell
The smallest unit that can live on its own. Every living thing is made of one or more cells.
Nucleus contains
Structure
Chromosome
A single DNA molecule packaged with proteins. Human cells usually carry 23 pairs, 46 chromosomes in all.
Nucleus is used by
Technology or method
Cloning
Producing a genetically identical copy. Dolly the sheep, reported in 1997, was cloned from an adult cell.
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Sources & further reading
The explanations on this page are our own summaries of these sources. Follow a link to read the original; if anything here disagrees with it, the original wins. How we choose and check sources.
Nucleus (opens the original in a new tab)
National Human Genome Research Institute. Talking Glossary of Genomic and Genetic Terms. National Human Genome Research Institute, NIH.
ReferenceGovernment sourceEducationalMolecular Biology of the Cell (4th edition) (opens the original in a new tab)
Alberts B, Johnson A, Lewis J, et al. (2002). Garland Science.
Free to read on NCBI Bookshelf. Standard reference for cell structure and molecular biology.
TextbookEducationalThe Cell: A Molecular Approach (2nd edition) (opens the original in a new tab)
Cooper GM (2000). Sinauer Associates.
Free to read on NCBI Bookshelf.
TextbookEducationalHutchinson-Gilford progeria syndrome (opens the original in a new tab)
MedlinePlus Genetics. MedlinePlus Genetics. U.S. National Library of Medicine, NIH.
ReferenceGovernment sourceEducational