BS 161 1st Edition Lecture 13 Outline of Last Lecture I Cell structure Outline of Current Lecture II Cell structure continued Current Lecture Endomembrane system consists of nuclear envelope endoplasmic reticulum ER Golgi apparatus GA lysosomes plasma membrane Vesicles small membrane enclosed transport things around the cell can fuse with membranes or other vesicles ER biosynthetic factory Smooth ER lacks ribosomes synthesizes lipids metabolizes carbohydrates detoxifies proteins Rough ER ribosomes stud its surface ribosomes synthesize glycoproteins proteins covalently bonded to carbohydrates distributes transport vesicles is a membrane factory for the cell Signal peptide stretch of amino acids that serve as zip code for protein tells it where to go Signal Recognition Particle SRP recognizes signal peptide GA consists of cisternae flattened membranous sacs modifies products of the ER adds sugar to proteins sorts and packages materials into transport vesicles Cis face receiving side inside Trans face shipping side outside Flow of materials through endomembrane system ER transport vesicles cis golgi stack transition vesicles trans golgi stack transport vesicles fusion with plasma membrane Phagocytosis cell eating some cells engulf other cells forms a food vacuole defense mechanism cells try to rid the body of bacteria and viruses Autophagy lysosomes use enzymes to recycles the cells own organelles and macromolecules Pinocytosis cell drinking all cells do it Mitochondria and chloroplasts are not part of endomembrane system have a double membrane have their own ribosomes bacteria like have their own DNA circular Mitochondria the sites of cellular respiration a metabolic process that generates ATP Chloroplasts found in plants and algae photosynthesis harvests light energy from the sun and turns it into chemical energy takes inorganic C and fixes it into CO2 Cytoskeleton a network of fibers extending through the cytoplasm organizes the cells structure and activities anchors many organelles Microtubules tubulin hollow rods maintenance of cell shape cell motility chromosome movements in cell division organelle movements Microfilaments actin solid rods maintenance of cell shape changes in cell shape muscle contraction cytoplasmic streaming cell motility cell division Intermediate filaments maintenance of cell shape anchorage of nucleus and other organelles formation of nuclear lamina
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