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DNA Structure The deoxyribonucleic acid, DNA, is a long chain of nucleotides which consist of Deoxyribose (a pentose = sugar with 5 carbons) Phosphoric Acid Organic (nitrogenous) bases (Purines - Adenine and Guanine, or Pyrimidines -Cytosine and Thymine). Bases. Purine (A+G).
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DNA Structure The deoxyribonucleic acid, DNA, is a long chain of nucleotides which consist of Deoxyribose (a pentose = sugar with 5 carbons) Phosphoric Acid Organic (nitrogenous) bases (Purines - Adenine and Guanine, or Pyrimidines -Cytosine and Thymine)
Bases Purine (A+G) Pyrimidine (T+C)
a nucleotide, a building block of DNA. It is a phosphate ester of a nucleoside Nucleotide Nucleoside
Note numbering system for carbons in ring Also note the difference between a ribose used for building DNA and one used for RNA
DNA and RNA chains are made by connecting nucleotides together via chemical bonds What is this chain RNA or DNA?
four different types of nucleotide possible in a DNA sequence, adenine, cytosine, guanine and thymine (ATCG) • Nucleotides are situated in adjacent pairs in the double helix. • Thymine and adenine can only make up a base pair • Guanine and cytosine can only make up a base pair
Double-stranded DNA is simply two chains of single- stranded DNA, positioned so their "bases" can interact with each other. • The sugar-and-phosphate 'backbone' is red, and the bases are blue. • the two strands travel in opposite directions; "anti-parallel". • The bases in the middle "pair up" with bases on the opposite strand, A+T, G+C • Hydrogen bonds hold stucture together
Genome- entire complement of genetic information. • Includes coding and non coding • Genes (exons and introns) • Alleles are different gene forms • Useful DNA for doing genome analysis
DNA isolation and purification • Important to obtain clean intact DNA in sufficient quantities to work with • Always do on ice Most purification procedures include many of the following steps • Lysis of cells to release contents including DNA • Treatment with EDTA to bind divalent cations • Proteinase K treatment to digest proteins and tissue away from DNA • Separation of DNA from other contaminants in cellular soup using chemical and physical differences e.g. differential solubilities, precipitation, binding to columns and centrifugation