CHEM237 Chapter Notes - Chapter 3-4: Streptococcus Pneumoniae, Acid Dissociation Constant, Threonine

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When phosphate is absent, it is considered a nucleoside. Pentose connects to nitrogen of the hexagon on pyridines, and the nitrogen of pentose on purines. Apparently phosphate group can go on c3" atom too. Avery, macleod and mccarty determined they could make dna transform from nonpathogenic r-type into virulent s form in pneumococci. Chargaff"s rule says [a]=[t], [c]=[g] and base composition of a given organism is independent. Hershey and chase found that dna, which was phosphate labeled, was found in progeny phages. 5" end consists of an oh on the 6" ch2 of a pentose, which is normally phosphate, and phosphate connects to the 3" carbon of the other nucleotides. Rna is more susceptible to base-catalyzed hydrolysis since its bases are more exposed. Denaturation of dna is dependent on base composition, ph and ionic strength (phosphate on backbone, counter ion can shield the negative charge and make it more stable)