BIOC 4403 Lecture Notes - Lecture 1: Prokaryote, Metaphase, Heterochromatin
23 Mar 2017
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Document Summary
Bacterial, archaeal, organellar genomes: often circular, sometimes linear dna, high gene density lack of repetitive dna, replication/transcription/translation all occur in same compartment, very little rna processing. Nuclear genomes: linear dna molecules, genes dispersed, varied amounts of repetitive dna, translation is uncoupled from replication and transcription, genes undergo a lot of rna processing. Two current theories of evolution: archaeal ancestor evolved new traits ancestor of eukaryotes, eukaryotes arose from fusion between an archaeon and bacterium. Eukaryotic genome is linear dna molecules associated in specific matter with large number of proteins: chromatin = combined dna-protein matter, chromosome: each dna/protein unit. # and size of chromosomes varies between species. Chromatin = highly dynamic continuously rearranging, changing protein position and degree of association: part of regulatory and structural processes, involved in gene expression, dna replication, cell division. Most eukaryotes: chromatin undergoes drastic contraction cycle for mitosis, relaxes for interphase. Condensed chromatin during cell division = minimal or no transcription.
