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A nucleosome is a complex made of 8 histones with DNA wrapped around it approximately twice. Histone 1 probably serves to help stabilize the further wrapping of the nucleosomes into a solenoid. All of this helps to get 6 feet of DNA in a cell much less than a millimeter across.
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∙ 9y ago
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∙ 14y agoA nucleosome is a complex made of 8 histones (2 each of H2a, H2b, H3 and H4) with DNA wrapped around it approximately twice. Histone 1 probably serves to help stabilize the further wrapping of the nucleosomes into a solenoid. All of this helps to get 6 feet of DNA in a cell much less than a millimeter across.
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∙ 16y agoHistones H1 and H5. These histones are thought to tether the linker DNA to the nucleosome core particles, although the details remain controversial.
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∙ 9y agoHistones are alkaline proteins that are the major protein components of chromatin. Chromatin is the union of DNA and proteins that make up the contents of a cell's nucleus.
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∙ 11y agoThe histone wrap around groups of histone and nucleosome coil up and forms a fiber
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∙ 12y agothe histone protein are short poly peptide chain contain a large number basicaminoacids these are lysine and arginin there for these protein are positively charges.
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∙ 12y agothey arent
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How DNA package itself?
What is a chromosome?In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes. Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure.To achieve the overall packing ratio, DNA is not packaged directly into final structure of chromatin. Instead, it contains several hierarchies of organization. The first level of packing is achieved by the winding of DNA around a protein core to produce a "bead-like" structure called a nucleosome. This gives a packing ratio of about 6. This structure is invariant in both the euchromatin and heterochromatin of all chromosomes.The second level of packing is the coiling of beads in a helical structure called the 30 nm fiber that is found in both interphase chromatin and mitotic chromosomes. This structure increases the packing ratio to about 40. The final packaging occurs when the fiber is organized in loops, scaffolds and domains that give a final packing ratio of about 1000 in interphase chromosomes and about 10,000 in mitotic chromosomes.Eukaryotic chromosomes consist of a DNA-protein complex that is organized in a compact manner which permits the large amount of DNA to be stored in the nucleus of the cell. The subunit designation of the chromosome is chromatin. The fundamental unit of chromatin is the nucleosome.Chromatin is the unit of analysis of the chromosome; chromatin reflects the general structure of the chromosome but is not unique to any particular chromosomeNucleosome is simplest packaging structure of DNA that is found in all eukaryotic chromosomes; DNA is wrapped around an octamer of small basic proteins called histones; 146 bp is wrapped around the core and the remaining bases link to the next nucleosome; this structure causes negative supercoiling.The nucleosome consists of about 200 bp wrapped around a histone octamer that contains two copies of histone proteins H2A, H2B, H3 and H4. These are known as the core histones. Histones are basic proteins that have an affinity for DNA and are the most abundant proteins associated with DNA. The amino acid sequence of these four histones is conserved suggesting a similar function for all.The length of DNA that is associated with the nucleosome unit varies between species. But regardless of the size, two DNA components are involved. Core DNA is the DNA that is actually associated with the histone octamer. This value is invariant and is 146 base pairs. The core DNA forms two loops around the octamer, and this permits two regions that are 80 bp apart to be brought into close proximity.Thus, two sequences that are far apart can interact with the same regulatory protein to control gene expression. The DNA that is between each histone octamer is called the linker DNA and can vary in length from 8 to 114 base pairs. This variation is species specific, but variation in linker DNA length has also been associated with the developmental stage of the organism or specific regions of the genome.The next level of organization of the chromatin is the 30 nm fiber. This appears to be a solenoid structure with about 6 nucleosomes per turn. This gives a packing ratio of 40, which means that every 1 µm along the axis contains 40 µm of DNA. The stability of this structure requires the presence of the last member of the histone gene family, histone H1. Because experiments that strip H1 from chromatin maintain the nucleosome, but not the 30 nm structure, it was concluded that H1 is important for the stabilization of the 30 nm structure.The final level of packaging is characterized by the 700 nm structure seen in the metaphase chromosome. The condensed piece of chromatin has a characteristic scaffolding structure that can be detected in metaphase chromosomes. This appears to be the result of extensive looping of the DNA in the chromosome.The last definitions that need to be presented are euchromatin and heterochromatin. When chromosomes are stained with dyes, they appear to have alternating lightly and darkly stained regions. The lightly-stained regions are euchromatin and contain single-copy, genetically-active DNA. The darkly-stained regions are heterochromatin and contain repetitive sequences that are genetically inactive.
What is the highest level of chromatin organisation?
nucleosome, 30-nm chromatin fiber, looped domainLook at the effect the earth's Schumann Resonance on human DNA.Also, how the Earth's resonance in increasing.
Why do tiny bubbles form on and amongst DNA strands during extraction?
When the detergent/salt/DNA mixture is agitated, the detergent, along with some inadvertently trapped gas, forms bubbles, and these bubbles may stick to the DNA and the histone proteins. They are not formed by any chemical reaction.
What is Tightly coiled form of DNA called?
Coiled up DNA, combined with protein histone, forms chromosomes.
What does mRnA tRnA and rRnA stand for and what do they do?
DNA is found in the nucleus of a eukaryotic cell as condensed chromatin fibres wrapped around histone proteins in the form of chromosomes. Mitchondria have their own DNA, mitochondrial DNA, which is found in the mitochondria. There are different types of RNA, ribosomal RNA, messenger RNA and transfer RNA. Ribosomal RNA (rRNA) is found in ribosomes and in the nucleolus where it is manufactured. messenger RNA (mRNA) can be found in the nucleus when it is translating DNA to mRNA in translation. It can also be found in the cytoplasm or attached to ribosomes that are transcribing the mRNA to synthesise polypeptides/protiens. transfer RNA (tRNA) can be found in the cytoplasm or around ribosomes where they transfer amino acids to the ribosome for protein synthesis in transcription.
How many different types of histone subunits are present in a nucleosome?
the number of histone subunits in a nucleosome is?
What is the difference between nucleosome and chromatosome?
Histone H1Histone H1 is found in a chromatosome but not in a nucleosome. Nucleosome with approximately 200bp of DNA and the histone octamer with H1 protein. but in chromatosome, the linher DNA of approximately 45bp is absent.
What are the subunits of DNA called?
Purines, Pryimidine and Nucleotide are the subunits of DNA.
What is the section of DNA called that has eight associated histone proteins?
Nucleosome
What is the fundamental repeating unit of organization in a eukaryotic chromosome?
The nucleosome is the basic unit that organizes the structure of an eukaryotic chromosome. The nucleosome is DNA wrapped around histone proteins which allows the DNA to condense into chromosomes.
How many times does DNA loop around the histone proteins in the nucleosome?
Twice
Structure of nucleosome and extent of chromatin condensation in metaphase chromosome?
nucleosomes are DNA bound by histone.....
A portion of a DNA molecule wound around a spool of histone protein is called a?
Such a structure is called a Nucleosome
DNA and histones form beadlike globule know as?
What are bead-like structures formed by DNA and histone molecules? Nucleosome
What is a nucleosome and what organic component is it primarily composed of?
Chromatin composed of tetramer of histones 2 copies each of Histone H2A, H2B, H3 and H4. DNA is bound on the nucleosome and uses 147 basepairs of DNA.
What is DNA wrapped around in a nucleosome?
They're called histone proteins. There are 8histones proteins in which a loop of DNA wraps around twice. Then another histone protein called the H1 linker binds them together.
What organic substance is a nucleosome composed of?
Nucleosomes are the basic repeating units of chromatin which is a combination of DNA and proteins that make up the content's of a cell's nucleus. Nucleosomes are made of a histone octamer which is comprised of two of the following histones: H2A, H2B, H3, and H4. The histone octamer is bound and wrapped around approximately 146 base pairs of DNA and an additional H1 histone is added and is wrapped around 20 more base pairs.
