{"id":6220,"date":"2013-08-09T13:15:04","date_gmt":"2013-08-09T13:15:04","guid":{"rendered":"https:\/\/schooltutoring.com\/help\/?p=6220"},"modified":"2014-12-02T08:26:58","modified_gmt":"2014-12-02T08:26:58","slug":"a-biology-review-of-dna","status":"publish","type":"post","link":"https:\/\/schooltutoring.com\/help\/a-biology-review-of-dna\/","title":{"rendered":"A Biology Review of DNA"},"content":{"rendered":"

Overview:\u00a0 What Is DNA?<\/strong>
\nGenes are made of DNA, short for deoxyribonucleic acid.\u00a0 It is a very long molecule made\u00a0 of the nitrogen-carrying bases adenine, guanine, thymine, and cytosine, phosphates, and the sugar deoxyribose.\u00a0 The long molecule is in an unique double helix shape, which allows a large amount of chemical information to be processed, stored, and replicated.<\/p>\n

How Was It Discovered?<\/strong>
\nScientists knew that the cell nucleus was made up of proteins and a substance called nucleic acid about thirty years before the model of the DNA molecule was put together, but they first thought that genes were contained in proteins within the cell nucleus.\u00a0 Researchers realized that genes were contained in nucleic acid after a series of experiments that involved strains of bacteria.\u00a0 One strain (S) caused mice to develop pneumonia and die but the other, closely-related strain (R) did not.\u00a0 When the S strain was killed and injected into mice, they did not die.\u00a0 However, if the inactive S strain was combined with the R strain, mice developed pneumonia and died.\u00a0 When DNA from the S strain was combined with the R strain, the R strain began developing lethal bacteria, leading scientists to conclude that the DNA, not protein carried genetic instructions.<\/p>\n

What Was Learned about DNA?<\/strong>
\nIn the early 1950s, several things were known about DNA.\u00a0 Its chemical composition was known, as well as its long, thin shape.\u00a0 Wilkins and Franklin discovered that the molecule had a distinctive cross-hatching pattern.\u00a0 They used a technique of first crystallizing DNA, then photographing it with X-rays.\u00a0 The molecule formed a long spiral.<\/p>\n

What Was the Model of DNA?<\/strong>
\nWatson and Crick developed a model for the DNA molecule that was based on existing knowledge.\u00a0 It was shaped in a double helix, with long side rails of sugars and phosphates connected by rungs of nitrogen-carrying bases.\u00a0 Adenine was only paired with thymine, and guanine with cytosine to account for the known chemical ratios. \u00a0Even the smallest virus contains thousands of nucleotide pairs that are arranged in order to carry coded genetic instructions.<\/p>\n

What Is DNA Replication?<\/strong>
\nEvery new cell has a complete and exact copy of the parent cell, copied through a replication process.\u00a0 DNA replicates before mitosis, as well as once during mitosis.\u00a0 The molecule splits down the middle, and enzymes cause nucleotides to join together with a new strand.\u00a0 Since adenine can only join with thymine, and guanine with cytosine, the sequence is preserved for the new cell.<\/p>\n

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Overview:\u00a0 What Is DNA? Genes are made of DNA, short for deoxyribonucleic acid.\u00a0 It is a very long molecule made\u00a0 of the nitrogen-carrying bases adenine, guanine, thymine, and cytosine, phosphates, and the sugar deoxyribose.\u00a0 The long molecule is in an unique double helix shape, which allows a large amount of chemical information to be processed, […]<\/p>\n","protected":false},"author":22,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":""},"categories":[3],"tags":[537,543,1213,1532],"class_list":["post-6220","post","type-post","status-publish","format-standard","hentry","category-biology","tag-dna","tag-double-helix","tag-nucleotides","tag-replication"],"acf":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/schooltutoring.com\/help\/wp-json\/wp\/v2\/posts\/6220","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/schooltutoring.com\/help\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/schooltutoring.com\/help\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/schooltutoring.com\/help\/wp-json\/wp\/v2\/users\/22"}],"replies":[{"embeddable":true,"href":"https:\/\/schooltutoring.com\/help\/wp-json\/wp\/v2\/comments?post=6220"}],"version-history":[{"count":0,"href":"https:\/\/schooltutoring.com\/help\/wp-json\/wp\/v2\/posts\/6220\/revisions"}],"wp:attachment":[{"href":"https:\/\/schooltutoring.com\/help\/wp-json\/wp\/v2\/media?parent=6220"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/schooltutoring.com\/help\/wp-json\/wp\/v2\/categories?post=6220"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/schooltutoring.com\/help\/wp-json\/wp\/v2\/tags?post=6220"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}