GEN-3000 Chapter Notes - Chapter 11: Histone H2B, Euchromatin, Metaphase
26 Oct 2017
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Condensing the dna to fit into the nucleus. No need to take up room if the dna isn"t being coded or isn"t needed. The positively charged histone holds onto the dna firmly. Nucleosome makes up the basic element of the chromatin. Nucleosome = h1+ pair of h2a, h2b, h3 and h4 + dna. The h1 histone acts as bridge b/w nucleosomes. Clamps onto where extra bit of dna falls from the histone. Applies structure to the solenoid and increases the compaction. Structure is changed to allow access to dna. With the dna so tightly compacted there needs to be a way to loosen the hold of histones on dna w/o loosening the whole string of nucleosomes. Will neutralize positive charge on the histone arms. Neutralizing charge weakens the histone hold on the dna. Occurs when a cell needs a lot of a product. Dna sequence contained in the centromere is critical. Cen region: minimal centromere necessary for kinetochore to form.
