BIOL239 Study Guide - Final Guide: Lac Repressor, Lac Operon, Rna Splicing
22 Oct 2016
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Watson-crick model of dna replication: original double helix, strands separate, complementary bases align opposite templates, enzymes link sugar-phosphate elements of aligned nucleotides into a continuous new strand. This model proposed a mechanism whereby dna replication is semiconservative-> in daughter molecules one strand is conserved form the parental molecule and the other is newly synthesized. Replication can be semiconservative (as before), conservative (complete duplication), or dispersive (random from new and old mixed together)-> three theories. Matthew meselson and franklin stahl came up with e(cid:448)ide(cid:374)(cid:272)e fo(cid:396) c(cid:396)i(cid:272)k(cid:859)s (cid:373)odel, studies (cid:449)ith (cid:272)o(cid:374)t(cid:396)olled isotopic composition of nucleotides incorporated into daughter dna strands (dna contains nitrogen 14 and. 15, centrifuge for a few days, equilibrium established between 14 and 15-> 15 lower in test tube) Prokaryotes have small circular chromosomes, dna replication is a complex process which occurs at a precise moment in the cell cycle (s-phase in eukaryotes), two steps-> initiation and elongation. E. coli dna replication is used as a model.
