Life Warning: You are not logged in. Your IP address will be publicly visible if you make any edits. If you log in or create an account, your edits will be attributed to your username, along with other benefits.Anti-spam check. Do not fill this in! === DNA === {{main|DNA}} Deoxyribonucleic acid or [[DNA]] is a [[molecule]] that carries most of the [[genetics|genetic]] instructions used in the growth, development, functioning and [[reproduction]] of all known living [[organism]]s and many viruses. DNA and [[RNA]] are [[nucleic acid]]s; alongside [[protein]]s and [[Polysaccharide|complex carbohydrates]], they are one of the three major types of [[macromolecules|macromolecule]] that are essential for all known forms of life. Most DNA molecules consist of two [[biopolymer]] strands coiled around each other to form a [[Nucleic acid double helix|double helix]]. The two DNA strands are known as [[polynucleotide]]s since they are composed of [[monomer|simpler units]] called [[nucleotide]]s.<ref>{{cite web |url=http://basicbiology.net/micro/genetics/dna |title=DNA |date=5 February 2016 |website=Basic Biology |access-date=15 November 2016 |last1=Purcell |first1=Adam |url-status=dead |archive-url=https://web.archive.org/web/20170105045651/http://basicbiology.net/micro/genetics/dna/ |archive-date=5 January 2017 }}</ref> Each nucleotide is composed of a [[nitrogenous base|nitrogen-containing]] [[nucleobase]]βeither [[cytosine]] (C), [[guanine]] (G), [[adenine]] (A), or [[thymine]] (T)βas well as a [[monosaccharide|sugar]] called [[deoxyribose]] and a [[phosphate group]]. The nucleotides are joined to one another in a chain by [[covalent bond]]s between the sugar of one nucleotide and the phosphate of the next, resulting in an alternating [[backbone chain|sugar-phosphate backbone]]. According to [[base pair]]ing rules (A with T, and C with G), [[hydrogen bond]]s bind the nitrogenous bases of the two separate polynucleotide strands to make double-stranded DNA. This has the key property that each strand contains all the information needed to recreate the other strand, enabling the information to be preserved during reproduction and cell division.<ref name="NYT-20150718-rn">{{cite news |last=Nuwer |first=Rachel |author-link=Rachel Nuwer|date=18 July 2015 |title=Counting All the DNA on Earth |url=https://www.nytimes.com/2015/07/21/science/counting-all-the-dna-on-earth.html |work=The New York Times |location=New York |access-date=18 July 2015 |url-status=live |archive-url=https://web.archive.org/web/20150718153742/http://www.nytimes.com/2015/07/21/science/counting-all-the-dna-on-earth.html |archive-date=18 July 2015 }}</ref> Within cells, DNA is organised into long structures called [[chromosome]]s. During [[cell division]] these chromosomes are duplicated in the process of [[DNA replication]], providing each cell its own complete set of chromosomes. Eukaryotes store most of their DNA inside the [[cell nucleus]].<ref>{{cite book |last=Russell |first=Peter |title=iGenetics |url=https://archive.org/details/igenetics0000russ_v6o1 |url-access=registration |publisher=Benjamin Cummings |location=New York |year=2001 |isbn=978-0-8053-4553-7}}</ref> <!--DNA was first isolated by [[Friedrich Miescher]] in 1869.<ref>{{cite journal |last=Dahm |first=R. |title=Discovering DNA: Friedrich Miescher and the early years of nucleic acid research |journal=Hum. Genet. |volume=122 |issue=6 |pages=565β581 |year=2008 |pmid=17901982 |doi=10.1007/s00439-007-0433-0|s2cid=915930 }}</ref> Its molecular structure was identified by [[James Watson]] and [[Francis Crick]] in 1953, whose model-building efforts were guided by [[X-ray diffraction]] data acquired by [[Rosalind Franklin]].<ref name="pmid24840850">{{cite journal |last=Portin |first=P. |title=The birth and development of the DNA theory of inheritance: sixty years since the discovery of the structure of DNA |journal=Journal of Genetics |volume=93 |issue=1 |pages=293β302 |year=2014 |pmid=24840850 |doi=10.1007/s12041-014-0337-4 |s2cid=8845393 }}</ref>--> Summary: Please note that all contributions to Christianpedia may be edited, altered, or removed by other contributors. If you do not want your writing to be edited mercilessly, then do not submit it here. You are also promising us that you wrote this yourself, or copied it from a public domain or similar free resource (see Christianpedia:Copyrights for details). Do not submit copyrighted work without permission! Cancel Editing help (opens in new window) Discuss this page