Chapter 10-pt 2

Chapter 10-pt 2 - ex: DNA binding proteins many acidic (-...

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Chapter 10 (Pg 266-270) Eukaryotic Chromosomes Intro diff btwn pro-/eu-karyotes is that prokaryotes only have 1 type of chrom C value – total amt of DNA in haploid genome of a species euchromatin - active level of chromatin structure heterochromatin - highly folded; high packing ratio; partially structural and also in regions where genes are so folded that they will be turned off; usu mitotic chrom Chromatin Structure histones: most abundant; small; much arg & lys net + charge (helps bind to – DNA) 5 types: H1, H2A, H2B, H3, H4 (aa seq of last 4 highly conserved) amt & proportions of histones relative to DNA constant from cell to cell in all eukaryotes crucial from chromatin packaging nonhistones: proteins associated w/ DNA apart from histones; less abundant
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Unformatted text preview: ex: DNA binding proteins many acidic (- charge) likely to bind + histones vary in # & type from cell to cell w/in an organism, at different times in same cell, & from organism to organism structure 10-nm chromatin (beads on a string)-beads are nucleosomes (2 of each of H2A, H2B, H3, H4 + 150 bp DNA wrapped 1.65 times-nucleosomes connected by linkers (strings); linkers vary w/in/among organisms 30-nm chrmomatin fiber: H1 binds to linker and middle of DNA segment-nucleosome technically involves H1-solenoid w/ 6 nucleosomes/spiral folded loops attach to proteinaceous scaffold w/ characteristic X shape of paired sister chromatids-scaffold associated regions (SARs) bind to nonhistone proteins to determine loops-loops arranged spirally around central chrom scaffold (looks like flower) packing ratio = length of unpacked/length of longest axis of packed...
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Chapter 10-pt 2 - ex: DNA binding proteins many acidic (-...

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