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it is a version without text of the File:Diagram human cell nucleus.svg: Date: 17 jun 2006 (original 27 april 2006) Source: edited with adobe ilustrator: Author: Mariana LadyofHats: Permission (Reusing this file)
Diagram of the nucleus showing the ribosome-studded outer nuclear membrane, nuclear pores, DNA (complexed as chromatin), and the nucleolus. The nucleus contains nearly all of the cell's DNA, surrounded by a network of fibrous intermediate filaments called the nuclear matrix, and is enveloped in a double membrane called the nuclear envelope.
In NMR studies of protein dynamics, the nitrogen-15 isotope is the preferred nucleus to study because its relaxation times are relatively simple to relate to molecular motions. This, however, requires isotope labeling of the protein. The T 1 and T 2 relaxation times can be measured using various types of HSQC-based experiments. The types of ...
This includes the transportation of RNA and ribosomal proteins from the nucleus to the cytoplasm, as well as proteins (such as DNA polymerase and lamins), carbohydrates, signaling molecules, and lipids moving into the nucleus. Notably, the nuclear pore complex (NPC) can actively mediate up to 1000 translocations per complex per second.
The nucleoplasm suspends structures within the nucleus that are not membrane-bound and is responsible for maintaining the shape of the nucleus. [2] The structures suspended in the nucleoplasm include chromosomes , various proteins , nuclear bodies , the nucleolus , nucleoporins , nucleotides , and nuclear speckles .
Although small molecules can enter the nucleus without regulation, [1] macromolecules such as RNA and proteins require association with transport factors known as nuclear transport receptors, like karyopherins called importins to enter the nucleus and exportins to exit. [2] [3]
Each human cell contains around two metres of DNA, which must be tightly folded to fit inside the cell nucleus. However, in order for the cell to function, proteins must be able to access the sequence information contained within the DNA, in spite of its tightly-packed nature. Hence, the cell has a number of mechanisms in place to control how ...
Each nucleosome is composed of a little less than two turns of DNA wrapped around a set of eight proteins called histones, which are known as a histone octamer. Each histone octamer is composed of two copies each of the histone proteins H2A, H2B, H3, and H4. DNA must be compacted into nucleosomes to fit within the cell nucleus. [2]