BIOL 243 Lecture Notes - Lecture 3: Dna Replication, Semiconservative Replication, Noncoding Dna
17 May 2016
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Document Summary
Various nitrogen isotopes are incorporated into the dna strands. The marked dna strands are tracked after each replication. Nucleotides can only be added onto the c-3" oh end, so dna polymerases synthesize only in the 5"-3" direction. The hydrolysis of ppi on the incoming carbon provides energy for the new phosphodiester bond. Dna polymerase can only add nucleotides onto existing dna strands, it can"t just create a strand de novo. Por esto, an rna primer (a short strand rna) and a 3"-oh serves as the start point. The rna primer is later removed because you can"t have an rna/dna mixed in one strand. Replisome is a molecular machine that carries out the dna replication process with the proteins it is composed of. It first unwinds dna, splits the dna, then initiates synthesis of complementary strands and then reanneals dna. Helicase unzips dna by breaking hydrogen bonds between bases.
