Related topics: protein , genes , genome , rna , genetic code
DNA
hideDeoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms and some viruses. The main role of DNA molecules is the long-term storage of information. DNA is often compared to a set of blueprints or a recipe, or a code, since it contains the instructions needed to construct other components of cells, such as proteins and RNA molecules. The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in regulating the use of this genetic information.
Chemically, DNA consists of two long polymers of simple units called nucleotides, with backbones made of sugars and phosphate groups joined by ester bonds. These two strands run in opposite directions to each other and are therefore anti-parallel. Attached to each sugar is one of four types of molecules called bases. It is the sequence of these four bases along the backbone that encodes information. This information is read using the genetic code, which specifies the sequence of the amino acids within proteins. The code is read by copying stretches of DNA into the related nucleic acid RNA, in a process called transcription.
Within cells, DNA is organized into X-shaped structures called chromosomes. These chromosomes are duplicated before cells divide, in a process called DNA replication. Eukaryotic organisms (animals, plants, fungi, and protists) store most of their DNA inside the cell nucleus and some of their DNA in the mitochondria (animals and plants) and chloroplasts (plants only). Prokaryotes (bacteria and archaea) however, store their DNA in the cell's cytoplasm. Within the chromosomes, chromatin proteins such as histones compact and organize DNA. These compact structures guide the interactions between DNA and other proteins, helping control which parts of the DNA are transcribed.
For more information about DNA, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
News tagged with dna
New Yorkers beware! New cockroach hits the Big Apple
Dec 24, 2009 |
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New Yorkers are used to fighting each other for space, but there may be a new contender in town according to a Rockefeller study that appears to have uncovered a new species of cockroach.
Molecular anchor links the 2 inheritable diseases Fanconi anemia and Bloom's syndrome
Dec 24, 2009 |
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A new study establishes a molecular link that bridges two rare inherited disorders and explains why these diseases result in genetic instability. The research, published by Cell Press in the December 24th issue of the journal ...
Faster, cheaper DNA sequencing method developed
Nanotechnology / Bio & Medicine
Dec 20, 2009 |
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(PhysOrg.com) -- Boston University biomedical engineers have devised a method for making future genome sequencing faster and cheaper by dramatically reducing the amount of DNA required, thus eliminating the ...
Broken genomes behind breast cancers
Dec 23, 2009 |
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The first detailed search of breast cancer genomes to uncover genomic rearrangements is published today. The team characterised the ways in which the human genome is broken and put back together in 24 cases of breast cancer.
Critical protein helps mend damaged DNA
Dec 24, 2009 |
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In order to preserve our DNA, cells have developed an intricate system for monitoring and repairing DNA damage. Yet precisely how the initial damage signal is converted into a repair response remains unclear. Researchers ...
Enzyme necessary for development of healthy immune system
Dec 22, 2009 |
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Mice without the deoxycytidine kinase (dCK) enzyme have defects in their adaptive immune system, producing very low levels of both T and B lymphocytes, the major players involved in immune response, according to a study by ...
Lung cancer and melanoma laid bare: First comprehensive analysis of two cancer genomes
Dec 16, 2009 |
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Research teams led by the Wellcome Trust Sanger Institute announce the first comprehensive analyses of cancer genomes. All cancers are caused by mutations in the DNA of cancer cells which are acquired during a person's lifetime. ...
Soil studies reveal rise in antibiotic resistance
Dec 23, 2009 |
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Antibiotic resistance in the natural environment is rising despite tighter controls over our use of antibiotics in medicine and agriculture, Newcastle University scientists have found.
Scientists get to the root of ancient case of sour grapes
Dec 18, 2009 |
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(PhysOrg.com) -- Scientists in Cambridge have discovered that a lowly grape variety grown by peasants - but despised by noblemen - during the Middle Ages was the mother of many of today’s greatest grape varieties, ...
Introns: A mystery renewed
Dec 10, 2009 |
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The sequences of nonsense DNA that interrupt genes could be far more important to the evolution of genomes than previously thought, according to a recent Science report by Indiana University Bloomington and ...
Scientists crack gene code of common cancers
Dec 17, 2009 |
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Two common forms of cancer have been genetically mapped for the first time, British scientists announced, in a major breakthrough in understanding the diseases.
Researchers revise long-held theory of fruit-fly development
Dec 17, 2009 |
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For decades, science texts have told a simple and straightforward story about a particular protein—a transcription factor—that helps the embryo of the fruit fly, Drosophila melanogaster, pattern tissues in a m ...
Scientists use DNA sequencing to attack lung cancer
Dec 16, 2009 |
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Aided by next-generation DNA sequencing technology, an international team of researchers has gained insights into how more than 60 carcinogens associated with cigarette smoke bind to and chemically modify human DNA, ultimately ...
The mammoths' swan song revised
Other Sciences / Archaeology & Fossils
Dec 14, 2009 |
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This is shown by samples of ancient DNA, analysed by an international team of research scientists under the leadership of Professor Eske Willerslev from Copenhagen University. Analyses of ancient DNA thereby ...
DNA needs a good editor: Researchers unravel the mysteries of DNA packaging
Dec 14, 2009 |
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Imagine a huge spool of film containing thousands of sequences of random scenes. Without a talented editor, a screening would have no meaning.
