BMS1062 Lecture Notes - Lecture 20: Base Pair, Escherichia Coli, Centromere
14 Aug 2018
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Explain how dna synthesis is different with respect to the lagging and leading strand. Describe how the fidelity of dna is maintained. Replication : priming can extend a polynucleotide chain, but cannot initiate one needs a primer involves dna primase which use ribonucleoside triphosphates to synthesize short rna primers complementary to dna. Dna polymerase extends dna chains in the 5" -> 3" direction after priming. While the other strand which runs in the opposite direction is discontinuous ( lagging strand) however dna molecule is antiparallel thus dna synthesis in one strand is continuous ( leading strand) thus this strand is formed in fragments. Okazaki fragments the lagging strand is now a mix of rna primer and dna. Dna polymerase i removes the rna primer with 5" - 3" exonuclease activity these gaps that are created are later filled with dna polymerase activity. Dna ligase then join the 3" ends of the gap to create long dna chains.
