BIO130H1 Lecture Notes - Lecture 5: Barr Body, Nucleosome, Cohesin
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BIO130H1 Full Course Notes
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If you isolate chromatin from cell in interphase, most of it (but not all of it) look like a 30 nm fibre. If 30 nm fibre is isolated and then experimentally de-(cid:272)o(cid:374)de(cid:374)sed, (cid:455)ou"ll see (cid:862)(cid:271)eads o(cid:374) a stri(cid:374)g(cid:863) for(cid:373) of (cid:272)hro(cid:373)ati(cid:374) Packaging of nucleosomes: h1 functions like a paperclip to clip the dna onto the histone octamer, cohesin may be involved in forming chromatin loops, loops may be attached to a nuclear scaffold to enable increased compaction. Thursday, january 18th, 2018: net result is that each dna molecule has been packaged into a mitotic chromosome that is 10 000 times shorter than its extended length, packing/unpacking requires atp. Note: there"s (cid:374)ot enough space to make everything euchromatin. Chromatin is remodelled to alter access to dna. Transcription factories regions with lots of substrates and enzymes necessary for transcription; optional to use for transcription can move particular genes to these places to get lots of transcription done.
