BIOL101 Lecture Notes - Lecture 9: Chromatin, Nuclear Pore, Histone H2B
14 Oct 2017
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How do eukaryotic cells, in general, compensate for higher surface area to volume ratio: compartmentalization, large area of internal membranes (e. g. endomembrane system) facilitating movement of proteins and lipids, specialized structures with specialized functions (e. g. mitochondria) Eukaryote cells size and energy: increased complexity requires more energy. Adapta&ons of larger cells: e. g. some nerve cells (neurons, up to 1 metre in length (e. g. some spinal neurons) Eukaryotic cell: distinct nucleus surrounded by nuclear envelope, membrane bound organelles- endomembrane system. Physically separates our hereditary material from the rest of the cell. Nuclear envelope: double membrane (phospholipid bilayer) connected to the er, ribosomes on outer surface, nuclear pore complex channel. Chromatin: dna plus associated proteins (histone and non-histone proteins) Composed of distinct regions: euchroma&n loosely packed regions. Genes ac?ve and transcrip?on occurring: heterochroma&n. Eukaryotic dna packing - histones: nucleosome o histone octamer (two molecules each of histones h2a, Eukaryotic dna packing - histones o linker dna connects adjacent nucleosomes.
