BIOL 252 1st Edition Lecture 3 Outline of Last Lecture I. HomeostasisII. GradientsIII. Feedback LoopsIV. The CellV. Key Terms in PhysiologyVI. MetabolismVII. Intro to Human PhysiologyOutline of Current LectureI. Plasma Membrane TransportII. Carbohydrates: Glucose MetabolismCurrent LectureI. Plasma Membrane Transporta. Passive: substance moves down concentration/electric gradient using only kineticenergyb. Diffusion: solutes move down concentration/electric gradient using only kinetic energyi. Rate factors1. Gradient steepness-faster for steeper gradient2. Temperature-faster for higher temperature3. Mass-slower for larger particle size4. Surface area-faster for larger surface area5. Diffusion distance-slow for larger distanceii. Simple diffusion1. Passive; w/out membrane transport proteins2. Nonpolar hydrophobic & uncharged polar moleculesiii. Facilitated1. Passive2. Solutes too polar or highly charged to cross by simple diffusion3. Assisted across membrane by integral membrane proteina. Channel-mediated (K+, Cl-, Na+, Ca2+)b. Carrier-mediated (glucose, fructose, galactose) must attachto carrierThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.iv. Osmosis1. Net movement of solvent through selective permeable membrane2. Solutes move from high to low3. Solvent move from low solute concentration to high solute concentration4. Move between phospholipid molecules via simple diffusion5. Move through integral proteins functioning as water channels (aquaporins)c. Active: polar or charged solutes needing to move against gradient (energy required)i. Primary1. Energy from ATP changes protein shape, pumps substance across membrane2. Na+/K+ pumpa. Expels Na+, brings in K+b. Maintain low [Na+] in cytosolc. Always workingii. Secondary1. Indirectly uses ATP2. Carrier protein binds to Na+ plus another substance, changes its shape so both can cross membrane simultaneouslya. Symporters: transporter moves substances in same directionb. Antiporters: transporter moves substances in opposite directionsII. Carbohydrates: Glucose Metabolisma. Termsi. Glucose: major energy source for ATP productionii. Glycogen: polymer of glucoseiii. Glycolysis: glucose breakdowniv. Gluconeogenesis: form glucose from non-CHO pre-cursorv. Glycogenolysis: glycogen => glucosevi. Glycogenesis: glucose => glycogen b. Glycolysisi. 1 molecule of glucose => 2 pyruvate, 2 NADH & 2H+, 2 ATPii. Anaerobiciii. Occurs in cytosol iv. Pyruvate converts to…1. Lactate in cytosol (anaerobic) via LDH2. Acetyl-CoA in mitochondrial matrix (aerobic) via PDHc. Key Enzymesi. Hexokinase: glucose => G-6-P (1st step)ii. PFK: major role in glycolysis rateiii. LDH: pyruvate => lactateiv. PDH: pyruvate => Acetyl-CoAd.
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