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cell nucleus
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| Schematic of typical animal cell, showing subcellular components. 1 nucleolus 2 nucleus 3 ribosome 4 vesicle 5 rough endoplasmic reticulum (ER) 6 Golgi apparatus 7 Cytoskeleton 8 smooth ER 9 mitochondria 10 vacuole 11 cytoplasm 12 lysosome 13 centrioles Credit: Wikipedia |
The nucleus is spheroidal in shape and separated from the cytoplasm by a double-membrane structure called the nuclear envelope. The nuclear envelope isolates and protects a cell's DNA from various molecules that could accidentally damage its structure or interfere with its processing. During processing, DNA is transcribed, or synthesized, into a special RNA, called mRNA. This mRNA is then transported out of the nucleus, where it is translated into a specific protein molecule. In prokaryotes, DNA processing takes place in the cytoplasm. Inside the nucleus of eukaryotes is the nucleolus.
Related category
• CELL BIOLOGY
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