DNA: Ìyàtọ̀ láàrin àwọn àtúnyẹ̀wò

Content deleted Content added
No edit summary
No edit summary
Ìlà 4:
DNA ni awon [[polymers|alarapupo]] gigun meji awon eyo kekere kan ton je [[nucleotide|nukleotidi]], pelu [[backbone chain|igbaeyin]] to je adipo [[Monosaccharide|suga]] ati [[phosphate|oniyofosforu]] ti won je sisopapao pelu awon ide [[ester|esteri]]. Awon igun mejeji yi jo doju de ona odi si ara won bi be won je [[antiparallel (biochemistry)|alaifarajo]]. Awon ihun jije lilemo suga kookan ni ikan ninu awon iru horo merin tounje [[nucleobases|ipilenukleu]] (lasan bi, ''awon ipile''). [[Nucleic acid sequence|Itelentele]] awon ipilenukleu mererin yi leba igbaeyin ni won un samioro iwifun. Iwifun yi je kika pelu lilo [[genetic code|amioro alabimo]], to utokasi itelentele awon [[amino acid|kikan amino]] ninu awon proteini. Amioro na je kika nipa sise àwòkọ awon ìnà DNA si inu kikan nukleiki RNA to baramu nnu igbese kan to unje [[transcription (genetics)|isawoko]].
 
Ninu awon ahamo DNA je gbigbajo si idimu gigun kan to unje [[chromosome|kromosomu]]. Nigba [[cell division|ipin ahamo]] awon kromosomu yi je didameji ninu igbese [[DNA replication|itunda DNA]], to si unpese fun ahamo kookan awon kromosomu pipe tikookan fun won. [[Eukaryote|Awon agbarajo eukarioti]] (awon [[animal|eranko]], [[plant|ogbin]], [[Fungus|ehu]], ati [[protist|protisti]]) ko opo awon DNA won pamo sinu [[cell nucleus|nukluenukleu ahamo]] ati awon DNA won miran sinu awon [[organelle|organeli]]s, such asbi [[mitochondria|mitokondria]] ortabi [[chloroplasts|adawo-ewe]].<ref>{{cite book | last = Russell | first = Peter | title = iGenetics | publisher = Benjamin Cummings | location = New York | year = 2001 | isbn = 0-8053-4553-1 }}</ref> InLafiwe contrast,si awon [[prokaryote|prokarioti]]s ([[bacteria|bakteria]] andati [[archaea|arkea]]) storeti theirwon unko DNA onlywon inpamo thesinu [[cytoplasm|adanuahamo]] nikan. WithinNinu theawon chromosomeskromosomu, awo proteini [[chromatin|kromatini]] proteins such asbi [[histone|histonu]]s compactundipo ando organizesi unsegbajo DNA. TheseAwon compactidimu structuresidipo guideyi theunselana interactionsibasepo betweenlarin DNA andati otherawon proteinsproteini miran, helpingnigba controltounsejanu whichawon partsapa ofDNA thewo DNAni areyio transcribedsawoko.
 
 
==IbereAwon ohun ini==
[[File:DNA chemical structure.svg|thumb|300px|Chemical structure of DNA. [[Hydrogen bond]]s shown as dotted lines.]]
 
DNA is a long [[polymer]] made from repeating units called [[nucleotide]]s.<ref>{{cite book | last = Saenger | first = Wolfram | title = Principles of Nucleic Acid Structure | publisher = Springer-Verlag | location = New York | year = 1984 | isbn = 0-387-90762-9 }}</ref><ref name=Alberts>{{cite book |last=Alberts |first=Bruce | coauthors=Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts and Peter Walters |title=Molecular Biology of the Cell; Fourth Edition |publisher=Garland Science|year=2002 |location=New York and London |url=http://www.ncbi.nlm.nih.gov/books/bv.fcgi?call=bv.View..ShowTOC&rid=mboc4.TOC&depth=2 |isbn=0-8153-3218-1 |oclc=145080076 48122761 57023651 69932405}}</ref><ref name=Butler>{{cite book | author=Butler, John M. | year=2001 | title=Forensic DNA Typing | publisher= Elsevier | isbn=978-0-12-147951-0 | oclc=223032110 45406517}} pp. 14–15.</ref> As first discovered by [[James D. Watson]] and [[Francis Crick]], the structure of DNA of all species comprises two helical chains each coiled round the same axis, and each with a pitch of 34&nbsp;[[Ångström]]s (3.4&nbsp;[[nanometre]]s) and a radius of 10&nbsp;[[Ångström]]s (1.0&nbsp;[[nanometre]]s).<ref name=FWPUB>{{cite journal| author = Watson J.D. and Crick F.H.C. | pmid=13054692 | doi = 10.1038/171737a0 | url= http://www.nature.com/nature/dna50/watsoncrick.pdf | title=A Structure for Deoxyribose Nucleic Acid | journal=Nature | volume=171 | pages=737–738 | year=1953 | format=PDF| issue = 4356 | bibcode=1953Natur.171..737W}}</ref> According to another study, when measured in a particular solution, the DNA chain measured 22 to 26&nbsp;[[Ångström]]s wide (2.2 to 2.6&nbsp;[[nanometre]]s), and one nucleotide unit measured 3.3&nbsp;Å (0.33&nbsp;nm) long.<ref>{{cite journal |author=Mandelkern M, Elias J, Eden D, Crothers D |title=The dimensions of DNA in solution |journal=J Mol Biol |volume=152 |issue=1 |pages=153–61 |year=1981 |pmid=7338906 |doi=10.1016/0022-2836(81)90099-1}}</ref> Although each individual repeating unit is very small, DNA polymers can be very large molecules containing millions of nucleotides. For instance, the largest [[human chromosome]], chromosome number 1, is approximately 220 million [[base pair]]s long.<ref>{{cite journal |author=Gregory S |title=The DNA sequence and biological annotation of human chromosome 1 |journal=Nature |volume=441 |issue=7091 |pages=315–21 |year=2006 |pmid=16710414 | doi = 10.1038/nature04727 |last2=Barlow |first2=KF |last3=McLay |first3=KE |last4=Kaul |first4=R |last5=Swarbreck |first5=D |last6=Dunham |first6=A |last7=Scott |first7=CE |last8=Howe |first8=KL |last9=Woodfine |first9=K|bibcode = 2006Natur.441..315G }}</ref>
 
In living organisms DNA does not usually exist as a single molecule, but instead as a pair of molecules that are held tightly together.<ref name=FWPUB>{{cite journal| author = Watson J.D. and Crick F.H.C. | pmid=13054692 | doi = 10.1038/171737a0 | url= http://www.nature.com/nature/dna50/watsoncrick.pdf | title=A Structure for Deoxyribose Nucleic Acid | journal=Nature | volume=171 | pages=737–738 | year=1953 | accessdate=4 May 2009|format=PDF| issue = 4356 | bibcode=1953Natur.171..737W}}</ref><ref name=berg>Berg J., Tymoczko J. and Stryer L. (2002) ''Biochemistry.'' W. H. Freeman and Company ISBN 0-7167-4955-6</ref> These two long strands entwine like vines, in the shape of a [[double helix]]. The nucleotide repeats contain both the segment of the backbone of the molecule, which holds the chain together, and a nucleobase, which interacts with the other DNA strand in the helix. A nucleobase linked to a sugar is called a [[nucleoside]] and a base linked to a sugar and one or more phosphate groups is called a [[nucleotide]]. Polymers comprising multiple linked nucleotides (as in DNA) are called a [[polynucleotide]].<ref name=IUPAC>[http://www.chem.qmul.ac.uk/iupac/misc/naabb.html Abbreviations and Symbols for Nucleic Acids, Polynucleotides and their Constituents] IUPAC-IUB Commission on Biochemical Nomenclature (CBN). Retrieved 03 January 2006.</ref>
 
The backbone of the DNA strand is made from alternating [[phosphate]] and [[carbohydrate|sugar]] residues.<ref name=Ghosh>{{cite journal |author=Ghosh A, Bansal M |title=A glossary of DNA structures from A to Z |journal=Acta Crystallogr D |volume=59 |issue=4 |pages=620–6 |year=2003 |pmid=12657780 |doi=10.1107/S0907444903003251}}</ref> The sugar in DNA is [[deoxyribose|2-deoxyribose]], which is a [[pentose]] (five-[[carbon]]) sugar. The sugars are joined together by phosphate groups that form [[phosphodiester bond]]s between the third and fifth carbon [[atom]]s of adjacent sugar rings. These asymmetric [[covalent bond|bonds]] mean a strand of DNA has a direction. In a double helix the direction of the nucleotides in one strand is opposite to their direction in the other strand: the strands are ''antiparallel''. The asymmetric ends of DNA strands are called the [[directionality (molecular biology)|5′]] (''five prime'') and [[directionality (molecular biology)|3′]] (''three prime'') ends, with the 5' end having a terminal phosphate group and the 3' end a terminal hydroxyl group. One major difference between DNA and RNA is the sugar, with the 2-deoxyribose in DNA being replaced by the alternative pentose sugar [[ribose]] in RNA.<ref name=berg/>
 
[[File:DNA orbit animated static thumb.png|thumb|upright|A section of DNA. The bases lie horizontally between the two spiraling strands.<ref>Created from [http://www.rcsb.org/pdb/cgi/explore.cgi?pdbId=1D65 PDB 1D65]</ref> Animated version at [[:File:DNA orbit animated.gif]].]]
 
The DNA double helix is stabilized primarily by two forces: [[hydrogen bond]]s between nucleotides and [[Stacking (chemistry)|base-stacking]] interactions among the [[aromatic]] nucleobases.<ref name="Yakovchuk2006">{{cite journal |author=Yakovchuk P, Protozanova E, Frank-Kamenetskii MD |title=Base-stacking and base-pairing contributions into thermal stability of the DNA double helix |journal=Nucleic Acids Res. |volume=34 |issue=2 |pages=564–74 |year=2006 |pmid=16449200 |pmc=1360284 |doi=10.1093/nar/gkj454 }}</ref> In the aqueous environment of the cell, the conjugated [[Pi bond|π bonds]] of nucleotide bases align perpendicular to the axis of the DNA molecule, minimizing their interaction with the [[solvation shell]] and therefore, the [[Gibbs free energy]]. The four bases found in DNA are [[adenine]] (abbreviated A), [[cytosine]] (C), [[guanine]] (G) and [[thymine]] (T). These four bases are attached to the sugar/phosphate to form the complete nucleotide, as shown for [[adenosine monophosphate]].
 
The nucleobases are classified into two types: the [[purine]]s, A and G, being fused five- and six-membered [[heterocyclic compound]]s, and the [[pyrimidine]]s, the six-membered rings C and T.<ref name=berg/> A fifth pyrimidine nucleobase, [[uracil]] (U), usually takes the place of thymine in RNA and differs from thymine by lacking a [[methyl group]] on its ring. Uracil is not usually found in DNA, occurring only as a breakdown product of cytosine. In addition to RNA and DNA a large number of artificial [[nucleic acid analogues]] have also been created to study the proprieties of nucleic acids, or for use in biotechnology.<ref>{{cite journal |author=Verma S, Eckstein F |title=Modified oligonucleotides: synthesis and strategy for users |journal=Annu. Rev. Biochem. |volume=67 |pages=99–134 |year=1998 |pmid=9759484 |doi=10.1146/annurev.biochem.67.1.99}}</ref>
 
[[File:DNA-ligand-by-Abalone.png|left|thumb|Major and minor grooves of DNA. Minor groove is a binding site for the dye [[Hoechst stain|Hoechst 33258]].]]
 
 
Jẹ́ kíkójáde láti "https://yo.wikipedia.org/wiki/DNA"