DNA,abbreviation of deoxyribonucleic acid, DNAEncyclopdia Britannica, Inc.organic chemical of complex molecular structure that is found in all prokaryotic and eukaryotic cells and in many viruses. DNA codes genetic information for the transmission of inherited traits.
A brief treatment of DNA follows. For full treatment, see genetics: DNA and the genetic code.
DNA: part of polynucleotide chainEncyclopdia Britannica, Inc.The chemical DNA was first discovered in 1869, but its role in genetic inheritance was not demonstrated until 1943. In 1953 James Watson and Francis Crick determined that the structure of DNA is a double-helix polymer, a spiral consisting of two DNA strands wound around each other. Each strand is composed of a long chain of monomer nucleotides. The nucleotide of DNA consists of a deoxyribose sugar molecule to which is attached a phosphate group and one of four nitrogenous bases: two purines (adenine and guanine) and two pyrimidines (cytosine and thymine). The nucleotides are joined together by covalent bonds between the phosphate of one nucleotide and the sugar of the next, forming a phosphate-sugar backbone from which the nitrogenous bases protrude. One strand is held to another by hydrogen bonds between the bases; the sequencing of this bonding is specifici.e., adenine bonds only with thymine, and cytosine only with guanine.
DNA origamiScience in Seconds (www.scienceinseconds.com) (A Britannica Publishing Partner)The configuration of the DNA molecule is highly stable, allowing it to act as a template for the replication of new DNA molecules, as well as for the production (transcription) of the related RNA (ribonucleic acid) molecule. A segment of DNA that codes for the cells synthesis of a specific protein is called a gene.
Crick, Francis Harry Compton: proposed DNA structureEncyclopdia Britannica, Inc.DNA replicates by separating into two single strands, each of which serves as a template for a new strand. The new strands are copied by the same principle of hydrogen-bond pairing between bases that exists in the double helix. Two new double-stranded molecules of DNA are produced, each containing one of the original strands and one new strand. This semiconservative replication is the key to the stable inheritance of genetic traits.
Within a cell, DNA is organized into dense protein-DNA complexes called chromosomes. In eukaryotes, the chromosomes are located in the nucleus, although DNA also is found in mitochondria and chloroplasts. In prokaryotes, which do not have a membrane-bound nucleus, the DNA is found as a single circular chromosome in the cytoplasm. Some prokaryotes, such as bacteria, and a few eukaryotes have extrachromosomal DNA known as plasmids, which are autonomous, self-replicating genetic material. Plasmids have been used extensively in recombinant DNA technology to study gene expression.
The genetic material of viruses may be single- or double-stranded DNA or RNA. Retroviruses carry their genetic material as single-stranded RNA and produce the enzyme reverse transcriptase, which can generate DNA from the RNA strand. Four-stranded DNA complexes known as G-quadruplexes have been observed in guanine-rich areas of the human genome.
Read more from the original source:
DNA | chemical compound | Britannica.com
- DNA database helps solve thousands of Texas crimes - January 3rd, 2013 [January 3rd, 2013]
- Revealed DNA - The Next Wave - Video - January 3rd, 2013 [January 3rd, 2013]
- DNA-Little Mix (Molly cover) - Video - January 5th, 2013 [January 5th, 2013]
- 'Junk DNA' made visible before the final cut - January 7th, 2013 [January 7th, 2013]
- 'Junk DNA' made visible before the final cut - January 7th, 2013 [January 7th, 2013]
- HUMAN DNA. A Speech To The Lord - Video - January 19th, 2013 [January 19th, 2013]
- 'Quadruple helix' DNA discovered in human cells - January 21st, 2013 [January 21st, 2013]
- 'Quadruple helix' DNA discovered in human cells - January 21st, 2013 [January 21st, 2013]
- Half a Million DVDs of Data Stored in Gram of DNA - January 25th, 2013 [January 25th, 2013]
- Jayy Star Feat DNA The Heredity (Don't Need Em) - Video - February 10th, 2013 [February 10th, 2013]
- Jayy Star Feat DNA The Heredity (Don't Need Em) - Video - February 10th, 2013 [February 10th, 2013]
- DNA evidence clears Texas man convicted in '81 killing - February 12th, 2013 [February 12th, 2013]
- DNA evidence clears Texas man convicted in '81 killing - February 12th, 2013 [February 12th, 2013]
- DNA Digital Videos presents EPIC Promo - Video - February 16th, 2013 [February 16th, 2013]
- 'Activating' RNA takes DNA on a loop through time and space - February 18th, 2013 [February 18th, 2013]
- 'Activating' RNA takes DNA on a loop through time and space - February 18th, 2013 [February 18th, 2013]
- New HTC One (Droid DNA) - Hands On UK - Video - February 20th, 2013 [February 20th, 2013]
- What is Brand DNA? BLVCK SCVLE Case Study - Video - October 2nd, 2013 [October 2nd, 2013]
- Nanded Train Accident: DNA test reveals mix up of Accident Dead Bodies | 10tv - Video - January 5th, 2014 [January 5th, 2014]
- DNA links executed convict to 1984 triple murder - January 11th, 2014 [January 11th, 2014]
- D-SPillz ft. Chucc Dizzle, DNA, Maniphest DestNE - Wishing Well (FREE DL LINK) - Video - January 16th, 2014 [January 16th, 2014]
- NOVA Extract Your DNA PBS359 - Video - January 17th, 2014 [January 17th, 2014]
- DNA:DECODE- Joe Rogan // ADN:DÉCODÉ- Joe Rogan - Video - January 27th, 2014 [January 27th, 2014]
- Campagna informativa "Banca Dati Nazionale DNA" - Video - February 6th, 2014 [February 6th, 2014]
- Congress cornered by BJP and AAP protests outside Arun ... - February 10th, 2014 [February 10th, 2014]
- DNA Test May Gauge Risk of Prostate Cancer's Return - April 10th, 2014 [April 10th, 2014]
- Blocking DNA repair mechanisms could improve radiation therapy for deadly brain cancer - April 10th, 2014 [April 10th, 2014]
- DNA matches Texas inmate in Houston cold cases - April 10th, 2014 [April 10th, 2014]
- Wisconsin Sheriff: DNA Ties Man to 1997 Slaying - April 10th, 2014 [April 10th, 2014]
- DNA ties man to 1997 murder of teen runaway - April 10th, 2014 [April 10th, 2014]
- DNA to pick out suspect, warts and all - April 10th, 2014 [April 10th, 2014]
- DNA-based logic gates operate inside cockroach cells - April 10th, 2014 [April 10th, 2014]
- DNA - Simple English Wikipedia, the free encyclopedia - April 10th, 2014 [April 10th, 2014]
- Deoxyribonucleic Acid (DNA) Fact Sheet - National Human ... - April 10th, 2014 [April 10th, 2014]
- What is DNA? - Genetics Home Reference - Your guide to ... - April 10th, 2014 [April 10th, 2014]
- DNA - Wikipedia, the free encyclopedia - April 10th, 2014 [April 10th, 2014]
- S k y p i feat Dodo - Postav sa zo dna (Official Video ryvok.... ) - Video - April 10th, 2014 [April 10th, 2014]
- Highlights: Eugenia Naro-Maciel, CUNY SI -- DNA Barcoding Freshwater Communities at Former Landfill - Video - April 10th, 2014 [April 10th, 2014]
- Highlights: George Ude, DNA Barcoding Projects at Bowie State and Godfrey Okoye Universities - Video - April 10th, 2014 [April 10th, 2014]
- Wonder of DNA 4/10/14 @ 8:00 pm EST - Video - April 10th, 2014 [April 10th, 2014]
- French police: all men at HS give DNA for rape case or be arrested - April 15th, 2014 [April 15th, 2014]
- French Polices Plan To DNA Test 500 High Schoolers Wouldnt Fly In U.S. - April 15th, 2014 [April 15th, 2014]
- 527 potential suspects in French high school rape lead to mass DNA test - April 15th, 2014 [April 15th, 2014]
- French authorities carry out DNA dragnet in school rape case - April 15th, 2014 [April 15th, 2014]
- DNA - New World Encyclopedia - April 15th, 2014 [April 15th, 2014]
- Motion Design Elemen DNA Strand Animation HD 2014 - Video - April 15th, 2014 [April 15th, 2014]
- 3D Pathway DNA Animation - Kawa 2014 - Video - April 15th, 2014 [April 15th, 2014]
- DNA Technologies - Video - April 15th, 2014 [April 15th, 2014]
- Assassin's Creed 4 [THC] vs [DNA] Competitive Artifact Assault - Video - April 15th, 2014 [April 15th, 2014]
- 12) Dr.Rasheed 10/04/2014 [DNA : Mitochondrial DNA - Replication in prokaryotes] - Video - April 15th, 2014 [April 15th, 2014]
- DNA Activation Plan Upgrades - Video - April 15th, 2014 [April 15th, 2014]
- DNA Wealth Blueprint - Andrew Fox + Peter Parks | DNA Wealth Blueprint Video Review - Video - April 15th, 2014 [April 15th, 2014]
- "DNA" das pessoas - Video - April 15th, 2014 [April 15th, 2014]
- Mass DNA sweep in privacy-loving France: Why no backlash? - April 15th, 2014 [April 15th, 2014]
- Monster DNA In-Earphones Unboxing - Video - April 15th, 2014 [April 15th, 2014]
- DJ RODRIGO - NOS SCRATCHS - Video - April 15th, 2014 [April 15th, 2014]
- [DBS] DNA MEP - Part 14 - Video - April 15th, 2014 [April 15th, 2014]
- Growing Up Poor Is Bad For Your DNA - Video - April 15th, 2014 [April 15th, 2014]
- RUG400 DNA-experience - Video - April 15th, 2014 [April 15th, 2014]
- RNA polymerase transcribing RNA from DNA - Video - April 15th, 2014 [April 15th, 2014]
- StorageDNA Discusses DNA Evolution 3.5 @ NAB 2014, Booth: SL10621 - Video - April 15th, 2014 [April 15th, 2014]
- DNA:DECODE- The Bronx // ADN:DCOD- Le Bronx - Video - April 15th, 2014 [April 15th, 2014]
- DNA Wealth Blueprint Scam? - Video - April 15th, 2014 [April 15th, 2014]
- Unlocking DNA technology in Nigeria - Video - April 15th, 2014 [April 15th, 2014]
- Mass DNA sweep in privacy-loving France: Why no backlash? (+video) - April 16th, 2014 [April 16th, 2014]
- 13) Dr.Rasheed 13/04/2014 [DNA : Replication of DNA] - Video - April 16th, 2014 [April 16th, 2014]
- Medbone | Empresa com apoio da DNA Cascais exporta para mais de 40 pases - Video - April 16th, 2014 [April 16th, 2014]
- 16) Dr.Abbas 16 [DNA : RNA synthesis in prokaryotes, eukaryotes & Synthesis of mRNA] - Video - April 16th, 2014 [April 16th, 2014]
- [DNA Wealth Blueprint Review] See DNA Wealth Blueprint Bonus Strategies For Facebook CPA Marketing - Video - April 16th, 2014 [April 16th, 2014]
- DnA's Evolution (live 4/11/14) - Part 1 - Video - April 16th, 2014 [April 16th, 2014]
- Attack of the B team w/tgudge- Dino DNA - Video - April 16th, 2014 [April 16th, 2014]
- Criminals Beware: Faces Recreated With ONLY DNA - Video - April 16th, 2014 [April 16th, 2014]
- Me Salva! GEN03 - Replicao do DNA - Parte 2 - Video - April 16th, 2014 [April 16th, 2014]
- Timolia Servervorstellung [2/5] | DNA #1 | DeusExMachina x TeMasket - Video - April 17th, 2014 [April 17th, 2014]
- Building on the DNA of Discovery: Vision Concept's exterior - Video - April 17th, 2014 [April 17th, 2014]
- DNA Tests Over Rape - Video - April 17th, 2014 [April 17th, 2014]
- Hydrogen bonding in DNA - Video - April 17th, 2014 [April 17th, 2014]
- How Is Your Emotional DNA Impacting Your Relationship? - Video - April 17th, 2014 [April 17th, 2014]
- Nucleic Acids 20: DNA to RNA to Proteins - Video - April 17th, 2014 [April 17th, 2014]
- Nucleic Acids 13: Even More About 3D Structure of DNA - Video - April 17th, 2014 [April 17th, 2014]