The name comes from its structure, which is a sugar and phosphate backbone which have bases sticking out from it--so-called bases. So that "deoxyribo" refers to the sugar and the nucleic acid refers to the phosphate and the bases. The bases go by the names of adenine, cytosine, thymine, and guanine, otherwise known as A, C, T, and G.
DNA is a remarkably simple structure. It's a polymer of four bases--A, C, T, and G--but it allows enormous complexity to be encoded by the pattern of those bases, one after another.
DNA is organized structurally into chromosomes and then wound around nucleosomes as part of those chromosomes. Functionally, it's organized into genes, of which are pieces of DNA, which lead to observable traits.
So the central dogma, so-called of molecular biology, is that genes, which are made of DNA, are made into messenger RNAs, which are then made into proteins. But for the most part, the observable traits of eye color or height or one thing or another of individuals come from individual proteins. Sometimes, we're learning in the last few years, actually, they come from RNAs themselves without being made into proteins--things like micro RNAs. But those still are relatively the exception for accounting for traits.
Deoxyribonucleic Acid DNA. Hewish, D. Chromatin sub-structure. The digestion of chromatin DNA at regularly spaced sites by a nuclear deoxyribonuclease. Biochem Biophys Res Commun 52 , Kornberg, R. Chromatin structure: A repeating unit of histones and DNA. Science , — Luger, K. Crystal structure of the nucleosome core particle at 2. Nature , — link to article.
Noll, M. Subunit structure of chromatin. Olins, A. Spheroid chromatin units v bodies. Olins, D. Chromatin history: Our view from the bridge. Nature Reviews Molecular Cell Biology 4 , — link to article. Oudet, P. Electron microscopic and biochemical evidence that chromatin structure is a repeating unit. Cell 4 , — Smith, C. ATP-dependent chromatin remodeling.
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Sex Determination in Honeybees. Annunziato, Ph. Citation: Annunziato, A. Nature Education 1 1 Each of us has enough DNA to reach from here to the sun and back, more than times. How is all of that DNA packaged so tightly into chromosomes and squeezed into a tiny nucleus? Aa Aa Aa. DNA, Histones, and Chromatin. The answer to this question lies in the fact that certain proteins compact chromosomal DNA into the microscopic space of the eukaryotic nucleus.
These proteins are called histones , and the resulting DNA-protein complex is called chromatin. It may seem paradoxical that proteins are added to DNA to make it more compact. However, if you have ever tried to store a garden hose, you know that it is much easier to do so if you begin by coiling the hose. Of course, coiling requires work, and energy is needed to perform work. Thus, within the nucleus, histones provide the energy mainly in the form of electrostatic interactions to fold DNA.
As a result, chromatin can be packaged into a much smaller volume than DNA alone. The Nucleosome: The Unit of Chromatin. Figure 2: Electron micrograph of chromatin: the beads on a string. Figure 3: Nucleosome core particle: ribbon traces for the bp DNA phosphodiester backbones brown and turquoise and eight histone protein main chains blue: H3; green: H4; yellow: H2A; red: H2B. The views are down the DNA superhelix axis for the left particle and perpendicular to it for the right particle.
For both particles, the pseudo-twofold axis is aligned vertically with the DNA center at the top. Nature , Figure 4: Electron micrograph of chromatin. References and Recommended Reading Bednar, J. Science , — Luger, K. Nature , — link to article Noll, M. Nature , — link to article Olins, A. Science , — Olins, D. Cell 4 , — Smith, C. Nucleic Acids Research 1 , — Wolffe, A. Chromatin: Structure and Function , 3rd ed. San Diego, Academic, Woodcock, C. Article History Close. Share Cancel.
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Chromosome Structure.
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