BIOLOGY 172 Lecture Notes - Lecture 6: Dna Replication, Topoisomerase, Telomerase
Document Summary
Dna polymerase can proofread: an error occurs every ~100,000 nucleotides are replicated, with polymerase proofreading, it occurs ~100,000,000, referred to as 3"-5" exonuclease activity. Elongation of dna replication: telomerase maintain length of telomeres, primer at 3" end wants to keep going, telomeres repetitive dna, g heavy, curing end of replication in. Rna primer, non-coding: rna primer is removed, but no 3" end, dna poly can"t extend, telomerase extends 3" end, telomeres shorten over time. Supercoiling: caused by topoisomerase, but topoisomerase also uncoils in dna replication, allows dna to become compact. Nucleosome: composed of histones, dna is wrapped around nucleosome, chromatin chromosomes wrapped around nucleosomes. Transcription: rna synthesized according to dna template, catalyzed by rna polymerase, occurs in genes only, rna polymerase, reads dna 3"-5", synthesizes 5"-3", catalyzes phosphodiester bonds, polymerization driven by energy released from energy rich phosphate bonds. Initiates without primer v: three major processes triphosphates, requires dna template and rntp (ribonucleotide i.
