Biochemistry 2280A Study Guide - Quiz Guide: Histone H1, Karyotype, Electron Microscope
4 Jun 2020
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Molecular biology dna compression: cells cannot accommodate dna required within a cell without use of dna packaging, different forms of dna packaging allow proper expression of genes, chromatin. Endonuclease digestion illustrates -> chromatin -> dna-protein complex. 2 each -> histones -> h2a, h2b, h3 & h4. Attaches outside -> nucleosome -> chromatosome: chromatosome. Nucleosome, dna & linker histone: 30nm chromatin fibre. Reduces length of dna (1/6th original length) -> to 1/7th (1/42nd) 4. 9cm molecule -> 1. 2mm: cryo-em -> linker histone h1 -> & interactions with nucleosome units -> 30nm chromatin fibre. Two curved, interwoven strands -> form (=) shape: higher levels of packaging than 30nm chromatin fibre -> not understood. Chromosome formed -> metaphase stage -> dna replication. Two daughter chromosomes of dna -> joined at centromere. Complete set of dna banding patterns produced -> stained: centromere: Joined together -> mistaken for chromosome breaks: euchromatin. >prevents tangling of dna: diseases associated with nuclear matrix & nuclear lamina:
