Deoxyribonucleic Acid Research Paper

651 Words 3 Pages
Deoxyribonucleic acid consists of a phosphate and deoxyribose backbone, and four different nitrogenous bases. These bases are adenine, guanine, cytosine, and thymine. Ribonucleic acid, the molecule formed in the transcription of DNA, is made up of phosphate, ribose, and adenine, guanine, cytosine, and uracil.
The backbone of DNA consists of a phosphate bonded to a deoxyribose molecule. Deoxyribose is a sugar containing five carbons, and it is called deoxyribose as it is missing an oxygen atom on C2. The sugar found in RNA is oxygenated at this carbon, and is called ribose.
The nucleotides of DNA are linked with phosphates at the 3' and 5' ends of the deoxyribose sugar. The 3' and 5' carbons of the deoxyribose molecule form single bonds with separate phosphate molecules. These bonds are 3’-5’ phosphodiester bonds. At one end of the DNA molecule will be a free 3' end, and at the other will be a free 5' end.
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The bases all happen to be heteroaromatic, as they contain two different elements in their aromatic system, namely carbon and nitrogen. The purines, containing two rings, are an example of a fused ring system, where in fact the electrons in what appear to be two distinct rings are delocalised across the whole ring system as one. The pyrimidines, which contain only one ring, also have delocalised electrons, as all aromatic molecules do. The double stranded DNA molecule is formed when these nitrogenous bases join via hydrogen bonds. Adenine bonds with thymine, and guanine bonds with cytosine. This was first strongly hinted at by the findings of Dr. Erwin Chargaff, a biochemist who discovered that the ratios of adenine to thymine and guanine to cytosine were approximately equal. The idea of base pairs existing also helped to explain the double helical shape of the double-stranded DNA molecule. The only difference is in DNA transcription, when adenine bonds with uracil in place of

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