BIOL 1090 Lecture Notes - Lecture 1: Sister Chromatids, Condensin, Chromatin
11 Mar 2016
School
Department
Course
Professor
Document Summary
Dna is double stranded and the strands are aniparallel. The strands are held together by hydrogen bonds between bases on opposing strands. One 360 degree turn has 10 base pairs=3. 4nm. *the size of dna maters when it comes to calculaing how much dna is packed into a chromosome when it is supercoiled in metaphase. Eukaryoic chromosomes are composed of proteins dna & rna as follows: The irst level of condensaion-packaging dna into nucleosomes produces an 11 nm ibre. Packaging dna as a supercoil into nucleosomes looks like this under a microscope, where the linker regions are suscepible to digesion by endonucleases. Dna is wrapped around a nucleosome core of 8 histone proteins and anchored by a 9th histone called histone h1 to form a complete nucleosome. 146 nucleoide pairs wrap around a nucleosome core. Genes range from 50 to 100,000 nucleoide pairs and would thus contain many nucleosomes.
