MMG 409 exam 3 notes

MMG 409 exam 3 notes - 4 Major phospholipids a....

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4 Major phospholipids a. Phosphatidylcholine b. Sphingomyelin c. Phosphatidylethanolamine d. Phospatidylserine i. (-) head so (-) net charge on cytosolic side Glycolipids – outer leaflet with carb exposed on cell surface Cholesterol – high temps – less fluid Peripheral – noncovalent Anchored – covalent Selectins – recognize specific carbs on cell surface Membrane transport proteins a. Passive – gases, hydrophobic, small polar b. Facilitated diffusion – polar and charged i. Carrier – transporters of sugars, AA, nucleosides, ii. Channel – open pores, any molecule with appropriate size and charge 1. Porins – ions and small polar 2. Ion channels – 1) Rapid 2) highly selective 3) not perfmanently open a. Ligand-gated – open b/c of neurotransmitters b. Voltage-gated – open b/c of changes in electrical potential c. Na+ channel – uses size to distinguish d. K+ channel – uses carbonyl oxygens (c=o) (Na+ to small) c. Active i. Ion pumps – maintain gradients, ATP-binding on cytosolic side 1. Na+-K+ - Na+ binds, ATP hydrolysis and P of pump, exposes to outside lower affinity, K+ opposite a. Establishes ion gradients to counterbalance osmotic pressure, 3Na, 2K 2. ABC – 2 transmembrane domains and 2 ATP-binding domains a. Mult. Drug Resistance (MDR1) small hydrophobic, flippases 3. Glucose + 2 Na+ in intestinal luman, Na+ moves favorable Endocytosis a. Receptor-mediated - form of pinocytosis; selective uptake, clathrin-coated receptors i. GTP-binding protein, Dynamin, assist with pit to vesicle formation b. Cholesterol Binding i. Cell-surface (pH=7) – endosome (pH=5) c. Receptors i. Recycled – cargo to lysosome ii. Down-regulation – travels with cargo to lysosome iii. Transcytosis – proceeds to different domain d. Clatherin-independent endocytosis – Caveolae – small invaginations in PM, lipid rafts e. Atherosclerosis – progressive deposition of lipid cells in inner layer of wall of artery
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Chitin – basic polymer of fungal cell wall, shells for crabs and exoskeletons (linear of N- acetylglucosamine) Cellulose – most abundant polymer, linear glucose Both joined by B(1->4) linkage, form microfibrils Hemi-cellulose – highly branched poly that are H-bonded to surface of microfibrils (stabilize) Pectins – cross-linked to microfibrils, branched poly w/ large # of (-) galacturonic acid o Bind to (+) ions and trap water to form gels ECM o Basal laminae – basement membranes, layers of epithelial cells rest Surround muscles, adipose and peripheral nerves, connective tissue Mechanical support for attached cells Generate signals that maintain cell survival Substratum for cell migration Separate adjacent tissues within an organ Barrier for macromolecules – prevent passage of proteins out of blood into tissues Barrier to invasion of tissue by cancer cells o 3 main molecules 1) collagen fibers – mechanical strength and resilience High tensile strength – 1 mm supports 10 kg
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MMG 409 exam 3 notes - 4 Major phospholipids a....

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