NUCLEAR PORES
Ribosomal proteins and all proteins of the cell nucleus, which are synthesized in cytoplasm, arrive into the nucleus through nuclear pores. Nuclear pores occupy about 5% of the nuclear surface and can be seen well in an electronic microscope (their diameter is 30 to 100 nm).
Nuclear pores transpierce nuclear envelopes of eukaryotic cells. In nuclear pores the outer membrane interlocks with the inner membrane. Pores are surrounded with large ringed structures (their inner diameter is about 80 nm) of 8 spherical ribonucleic protein particles. A ribonucleic protein particle placed in the center of a pore is connected with the rings by thin chords. These structures are called nuclear pore complexes. Through nuclear pores a cell nuclear and cytoplasm exchange various substances. For example, messenger RNA and ribosomal subunits go out into cytoplasm through nuclear pores.
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Supplementary information
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