Function of Nuclear Pores
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Nuclear pores are protein-based channels in the nuclear envelope. They regulate the movement of molecules from the nucleus to the cytoplasm, and vice versa. In most eukaryotic cells, the nucleus is enclosed by this nuclear membrane in order to separate it from the cytoplasm. Many higher eukaryotic cells have as many as 2,000 nuclear pore complexes in the nuclear membrane of each cell. This membrane or envelope keeps the DNA safe, and contains it within the nucleus. Despite the presence of this barrier, communication still has to take place between the nucleus and the cytoplasm, so the nuclear pores serve as transportation and communication channels. This transportation and communication has to be able to happen quickly for cell regulation and health. Some molecules are simply small enough to pass through the pores, but larger molecules must be recognized by different signal sequences before being allowed to diffuse through the nuclear pores via a concentration gradient. Some substances, like carbohydrates, lipids, and even ribosomes are able to pass through quite easily, while RNA and some proteins must be "cleared" for release through signal sequences within the nucleus. |
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