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== 2024.04.05 ==
 
=== DNA ===
'''Deoxyribonucleic acid'''&nbsp;([https://en.wikipedia.org/wiki/Help:IPA/English /diːˈɒksɪˌraɪboʊnjuːˌkliːɪk,&nbsp;-ˌkleɪ-/]&nbsp;[https://en.wikipedia.org/wiki/File:En-us-Deoxyribonucleic_acid.ogg <sup>ⓘ</sup>];[https://en.wikipedia.org/wiki/DNA#cite_note-1 <sup>[1</sup>]]&nbsp;'''DNA''') is a&nbsp;[https://en.wikipedia.org/wiki/Polymer polymer]&nbsp;composed of two&nbsp;[https://en.wikipedia.org/wiki/Polynucleotide polynucleotide]&nbsp;chains that coil around each other to form a&nbsp;[https://en.wikipedia.org/wiki/Nucleic_acid_double_helix double helix]. The polymer carries&nbsp;[https://en.wikipedia.org/wiki/Genetics genetic]&nbsp;instructions for the development, functioning, growth and&nbsp;[https://en.wikipedia.org/wiki/Reproduction reproduction]&nbsp;of all known&nbsp;[https://en.wikipedia.org/wiki/Organism organisms]&nbsp;and many&nbsp;[https://en.wikipedia.org/wiki/Virus viruses]. DNA and&nbsp;[https://en.wikipedia.org/wiki/Ribonucleic_acid ribonucleic acid]&nbsp;(RNA) are&nbsp;[https://en.wikipedia.org/wiki/Nucleic_acid nucleic acids]. Alongside&nbsp;[https://en.wikipedia.org/wiki/Protein proteins],&nbsp;[https://en.wikipedia.org/wiki/Lipids lipids]&nbsp;and complex carbohydrates ([https://en.wikipedia.org/wiki/Polysaccharide polysaccharides]), nucleic acids are one of the four major types of&nbsp;[https://en.wikipedia.org/wiki/Macromolecule macromolecules]&nbsp;that are essential for all known forms of&nbsp;[https://en.wikipedia.org/wiki/Life life]. The two DNA strands are known as polynucleotides as they are composed of simpler&nbsp;[https://en.wikipedia.org/wiki/Monomer monomeric]&nbsp;units called&nbsp;[https://en.wikipedia.org/wiki/Nucleotide nucleotides].[https://en.wikipedia.org/wiki/DNA#cite_note-2 <sup>[2</sup>]][https://en.wikipedia.org/wiki/DNA#cite_note-3 <sup>[3</sup>]]&nbsp;Each nucleotide is composed of one of four&nbsp;[https://en.wikipedia.org/wiki/Nitrogenous_base nitrogen-containing]&nbsp;[https://en.wikipedia.org/wiki/Nucleobase nucleobases]&nbsp;([https://en.wikipedia.org/wiki/Cytosine cytosine]&nbsp;[C],&nbsp;[https://en.wikipedia.org/wiki/Guanine guanine]&nbsp;[G],&nbsp;[https://en.wikipedia.org/wiki/Adenine adenine]&nbsp;[A] or&nbsp;[https://en.wikipedia.org/wiki/Thymine thymine]&nbsp;[T]), a&nbsp;[https://en.wikipedia.org/wiki/Monosaccharide sugar]&nbsp;called&nbsp;[https://en.wikipedia.org/wiki/Deoxyribose deoxyribose], and a&nbsp;[https://en.wikipedia.org/wiki/Organophosphate phosphate group]. The nucleotides are joined to one another in a chain by&nbsp;[https://en.wikipedia.org/wiki/Covalent_bond covalent bonds]&nbsp;(known as the&nbsp;[https://en.wikipedia.org/wiki/Phosphodiester_bond phosphodiester linkage]) between the sugar of one nucleotide and the phosphate of the next, resulting in an alternating&nbsp;[https://en.wikipedia.org/wiki/Backbone_chain sugar-phosphate backbone]. The nitrogenous bases of the two separate polynucleotide strands are bound together, according to&nbsp;[https://en.wikipedia.org/wiki/Base_pair base pairing]&nbsp;rules (A with T and C with G), with&nbsp;[https://en.wikipedia.org/wiki/Hydrogen_bond hydrogen bonds]&nbsp;to make double-stranded DNA. The complementary nitrogenous bases are divided into two groups, the single-ringed&nbsp;[https://en.wikipedia.org/wiki/Pyrimidine pyrimidines]&nbsp;and the double-ringed&nbsp;[https://en.wikipedia.org/wiki/Purine purines]. In DNA, the pyrimidines are thymine and cytosine; the purines are adenine and guanine. Both strands of double-stranded DNA store the same&nbsp;[https://en.wikipedia.org/wiki/Central_dogma_of_molecular_biology#Biological_sequence_information biological information]. This information is&nbsp;[https://en.wikipedia.org/wiki/DNA_replication replicated]&nbsp;when the two strands separate. A large part of DNA (more than 98% for humans) is&nbsp;[https://en.wikipedia.org/wiki/Non-coding_DNA non-coding], meaning that these sections do not serve as patterns for&nbsp;[https://en.wikipedia.org/wiki/Primary_protein_structure protein sequences]. The two strands of DNA run in opposite directions to each other and are thus&nbsp;[https://en.wikipedia.org/wiki/Antiparallel_(biochemistry) antiparallel]. Attached to each sugar is one of four types of nucleobases (or&nbsp;''bases''). It is the&nbsp;[https://en.wikipedia.org/wiki/Nucleic_acid_sequence sequence]&nbsp;of these four nucleobases along the backbone that encodes genetic information.&nbsp;[https://en.wikipedia.org/wiki/RNA RNA]&nbsp;strands are created using DNA strands as a template in a process called&nbsp;[https://en.wikipedia.org/wiki/Transcription_(genetics) transcription], where DNA bases are exchanged for their corresponding bases except in the case of thymine (T), for which RNA substitutes&nbsp;[https://en.wikipedia.org/wiki/Uracil uracil]&nbsp;(U).[https://en.wikipedia.org/wiki/DNA#cite_note-4 <sup>[4</sup>]]&nbsp;Under the&nbsp;[https://en.wikipedia.org/wiki/Genetic_code genetic code], these RNA strands specify the sequence of&nbsp;[https://en.wikipedia.org/wiki/Amino_acid amino acids]&nbsp;within proteins in a process called&nbsp;[https://en.wikipedia.org/wiki/Translation_(genetics) translation]. Within eukaryotic cells, DNA is organized into long structures called&nbsp;[https://en.wikipedia.org/wiki/Chromosome chromosomes]. Before typical&nbsp;[https://en.wikipedia.org/wiki/Cell_division cell division], these chromosomes are duplicated in the process of DNA replication, providing a complete set of chromosomes for each daughter cell.&nbsp;[https://en.wikipedia.org/wiki/Eukaryote Eukaryotic organisms]&nbsp;([https://en.wikipedia.org/wiki/Animal animals],&nbsp;[https://en.wikipedia.org/wiki/Plant plants],&nbsp;[https://en.wikipedia.org/wiki/Fungus fungi]&nbsp;and&nbsp;[https://en.wikipedia.org/wiki/Protist protists]) store most of their DNA inside the&nbsp;[https://en.wikipedia.org/wiki/Cell_nucleus cell nucleus]&nbsp;as&nbsp;[https://en.wikipedia.org/wiki/Nuclear_DNA nuclear DNA], and some in the&nbsp;[https://en.wikipedia.org/wiki/Mitochondrion mitochondria]&nbsp;as&nbsp;[https://en.wikipedia.org/wiki/Mitochondrial_DNA mitochondrial DNA]&nbsp;or in&nbsp;[https://en.wikipedia.org/wiki/Chloroplast chloroplasts]&nbsp;as&nbsp;[https://en.wikipedia.org/wiki/Chloroplast_DNA chloroplast DNA].[https://en.wikipedia.org/wiki/DNA#cite_note-5 <sup>[5</sup>]]&nbsp;In contrast,&nbsp;[https://en.wikipedia.org/wiki/Prokaryote prokaryotes]&nbsp;([https://en.wikipedia.org/wiki/Bacteria bacteria]&nbsp;and&nbsp;[https://en.wikipedia.org/wiki/Archaea archaea]) store their DNA only in the&nbsp;[https://en.wikipedia.org/wiki/Cytoplasm cytoplasm], in&nbsp;[https://en.wikipedia.org/wiki/Circular_chromosome circular chromosomes]. Within eukaryotic chromosomes,&nbsp;[https://en.wikipedia.org/wiki/Chromatin chromatin]&nbsp;proteins, such as&nbsp;[https://en.wikipedia.org/wiki/Histone histones], compact and organize DNA. These compacting structures guide the interactions between DNA and other proteins, helping control which parts of the DNA are transcribed.<br/> <br/> full text link&nbsp;:&nbsp;[https://en.wikipedia.org/wiki/DNA https://en.wikipedia.org/wiki/DNA]
=== RNA ===
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