BIOCHEM 2B03 Chapter Notes - Chapter 11: Interphase, Thymidine Triphosphate, Dna Supercoil
6 Sep 2013
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Document Summary
The nucleotide sequence of dna can be determined from the electrophoretic migration of a defined set of polynucleotide fragments. Chain termination/dideoxy method more common protocol for nucleic acid sequencing: fredrick sanger, relies on enzymatic replication of the dna to be sequenced. Sanger"s chain termination/dideoxy method uses dna replication to generate a defined set of polynucleotide fragments. All four deoxynucleoside triphosphates (datp, dgtp, dctp, dttp) which are the substrate for. No nucleophile to attach the 5" phosphate. Watson-crick base pairs (a:t pair and g:c pair) have virtually identical dimensions. Dna double helix is a stable structure: h-bonds. H bonds form between h2o and bases when strands are separated. Polar atoms in sugar-phosphate backbone form external h bonds with h2o: electrostatic interactions. Negatively charged phosphate groups along the sugar-phosphate backbone keep strands apart except when base pairing occurs. Charges become electrostatically shielded from one another because divalent cations (i. e. mg2+) bind strongly to the anionic phosphates: van der waals and hydrophobic interactions.
