BIOL 118 Lecture Notes - Lecture 8: Endosome, Signal Recognition Particle, Endomembrane System
1 Mar 2017
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Nuclear envelope: double membrane (2 lipid bilayer membranes, has nuclei pores=openings in the envelope regulate what goes in and out. Heterochromatin: density packed dna at the edges, usually inactive genes. Euchromatin: loosely packed dna inside, usually active genes. Things enter the nucleus through the nuclear pore complexes. Messenger rna and ribosomes leave the nucleus through these. Enzymes for dna and rna synthesis, etc. Must enter through the nuclear pore complexes. Proteins must have a 17-amino acid long nuclear localization signal (nls: acts as a zip code to mark the proteins to go to the nucleus. Many ribosomes are found in the cytosol. Enzymes to detoxify reactive molecules: detoxify hydrogen peroxide (h2o2) into harmless products. Single-membrane-bound centers for: digestion, waste processing. Animal lysosomes: an acid interior (ph 5. 0, and contain digestive enzymes. Endocytosis: pinching off of the plasma membrane resulting in uptake of material from outside of the cell, types of endocytosis.
