FABS 210 Lecture Notes - Lecture 7: Primase, Dna Gyrase, Okazaki Fragments
16 Jan 2018
School
Department
Course
Professor
Document Summary
Supercoiled helix - dna is further twisted to save space. Negative supercoiling: double helix is under wound. Relaxed dna - dna has number of turns predicted by number of base pairs. Negative supercoiling - is predominantly found in nature. Mostly all chromosomes are circular, a gyrase causes a nick and opens it up allowing the chromosome to turn on itself making it become supercoiled. Genome - entire complement of genes in cell or virus including regulatory elements. Plasmids - replicate separately from chromosome, majority are double stranded and most are circular. Bene cial for cells but not vital for them to live. Selective pressure - if not bene cial or useful bacteria will not bother to replicate them and they are lost. As soon as you release that pressure the gene will die, for that gene to continue to live the cells need to keep transcribing that gene to create that selective gene.
