Biology 1202B Lecture Notes - Lecture 11: Telomerase, Deoxyribonuclease, Noncoding Dna
Watson and crick realized that complementary base pairing could explain how dna replicates. Semi-conservative replication- each of the two strands of original dna serve as a template for a new dna double helix. Used nonradioactive heavy nitrogen isotope to tag parental dna to be distinguished apart from newly synthesized dna. Grew e. coli on medium with 15n. Incorporated in dna o o: centrifuged mixture- dna of different densities separate into bands. Assemble nucleotide chains in the 5"-3" direction. Complimentary nucleotide triphosphate pairs: deoxyribonucleotide triphosphates are the substrates for the polymerization reaction catalyzed by dna polymerase. At one end, a phosphate group is bound to the 5" carbon of a deoxyribose sugar and at the other end, a hydroxyl group is bonded to the 3" carbon. Dna polymerase can only add a nucleotide to the 3" end of an existing chain. Polymerases share the shape of a closed human hand.