BIOL 2021 Lecture Notes - Lecture 6: Ribosomal Rna, Transfer Rna, Exocytosis
12 May 2013
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Document Summary
Lecture 6: chapter 12 compartments and protein sorting. Increase surface area of membranes: divide cytoplasm into functionally specialized spaces. Nucleus + cytosol: connected by nuclear pores. Secetretory and exocytotic organelles, er, golgi, endosomes, lysosomes: connected by transport vesicles. Plastids chloroplasts and derivatives (plants: mito and chloros not connected to others because they have their own dna, protein synth, mainly import protein from cytosol. Lumen of er is outside the cell, vesicle traffic connects organelles. Problem: most proteins made on ribosomes in cytosol, how do we get them into organelles: sorting signals amino acid sequence for location built into the coding dna, no signal stay in cytosol. Signal patch dscts: patch after the protein folds up, patch formed by 3d structure after fold. Gated transport != gated ion channels: cytosol to nucleus, uses nuclear pores for large molecules. Transmembrane transport: cytosol to lumen of prganelles, protein translocator, topologically different space.
