BIO130H1 Lecture Notes - Lecture 6: Histone H2B, Nucleosome, Nuclear Membrane
31
BIO130H1 Full Course Notes
Verified Note
31 documents
Document Summary
Phases include: interphase, prophase, prometaphase, metaphase, anaphase, telophase and cytokinesis. Starts with dna double helix (2 nm in diameter) Dna wraps itself around h1 histone: core histone is 8 subunits, this is called nucleosome core particle, nucleosome filament is 10 nm in diameter. Gets compacted in zig-zag shape, 30 nm fiber. Protein scaffold (looks like daisy) and looped domains form: cohesin protein is like centre of daisy. Sister chromatids form: condensin makes protein scaffold in chromatids. The net result is that each dna molecule has been packaged into a mitotic chromosome that is 10000 times shorter than its extended length. Top picture: chromatin isolated from cell in interphase. Bottom: experimentally decondensed chromatin: little nodes show nucleosomes. Rich in lysine and arginine: positive charge neutralizes negative charge of dna. Four core histone proteins: h2a, h2b, h3, and h4, pair of each in octamer core, total 8, one linker histone (h1) Two models of intermediate chromatin condensation: zig-zag.
