REVIEW EXAM 2 Glucose concentration The epithelial cells of the digestive tract want to continually bring glucose from the outside environment into the body for processing and or storage whether that means moving glucose with or against its gradient 02 04 2015 These cells also want to prevent stored glucose from flowing back into the gut because this would deplete our glucose reserve inside the cell By using active transport rather than a free process such as facilitated diffusion the cells of the digestive tract ensure that the movement of glucose occurs in one direction into the cell Other cells e g red blood cells use facilitated diffusion to transport glucose from the extracellular fluid into the cell because they do not need to store glucose within Since the concentration of glucose is higher in the IF compared to the intracellular fluid facilitated diffusion can ensure that glucose flows into these cells when necessary it would be a waste of ATP to use active transport for these other cells Substrate Phosphorylation Substrate Pi bound ADP XPi ATP Oxidative Pi unbound ETC o glycolysis krebs creatine Free Radicals steal electrons from something else kill the other thing want more free radicals to kill of things Glycolysis sugar molecule intracellular cytosol products o aerobically pyruvate o anaerobic lactic acid o CoNZ s o Hydrogen o 2Net ATP molecules o ATP concentration determines how much we run glycolysis Krebs Cycle Start with pyruvate lipids proteins Products o Co2 o CoNZ s o 2 ATP ETC take place in mitochondria regulated the same as glycolysis Start off with H ions and CoNZ s Need oxygen present Byproducts o 34 ATP o H2O or free radicals o Recycled coENZ s If not oxygen present cant recycle coenzymes uses byproducts of krebs and glycolysis Primary Transport ATP directly involved in it STORED ENERGY SYSTEM can use to build up energy use stored energy to run secondary active transport o Na K pump use only half of ATP energy use half to flip protein as long as ATP present can keep running every time you have something binding unbinding to a protein always shape shape ATP binds shape change increases affinity of Na Na binds get shape change causes ATP break apart Which causes another shape change and causes a shape change ect Series of shape changes Secondary Transport ATP not directly involved but know something is going moving against its gradient Countertransport going against Cotransport both going in cell same direction have to be going in same transporter Both have nothing to do with the gradient Can happen in either primary or secondary transport Endocytosis Exocytosis need cholesterol ATP endo moving outside to in interstitial fluid o functions of endocytosis transcellular transport endosomal processing destroying engulfed materials and recycling the membrane Transcellular transport occurs due to the tight junctions between the cells The materials that need to get to the other side of the cell cannot due to these junctions and therefore have to be engulfed by the cell and travel through it to the other side where it exits As far as destroying engulfed materials I had written down something about immune system cells I think what I was trying to remind myself of was that the cell takes in something most likely harmful like an immune cell takes in a pathogen and destroys it exo moving in to outside cytosol both are created vesicles created from cholesterol and ATP transport big polar things across membrane Osmotic Pressure CANT have osmotic pressure in humans membranes moving not immobile if cell is gaining size NO OP water pressing against cell trying to get in bigger difference in gradient o higher OP Never gonna out gradients Hypotonic Hypertonic Isotonic Have really high concentration of solute outside the cell where is water gonna wanna move OUT water follows solutes cell will shrink HYPERtonic outside of cell HYPOtonic few solutes on outside water will wanna move inside wants to dilute inside of cell cell will swell HYPOtonic outside HYPERtonic Passive Transport Ion Channels nothing interacts with it big door walk through it o w gradient and no energy o voltage ligand mechanical gates ex of mechanical stretching of bladder o aquaporin s water Facilitated diffusion w gradient no energy cost something that isn t usually the ion is whats its binding too revolving door problem with FD get overloaded saturated Receptor protein that ligand binds too or whatever it binds too Desmosome protein linkage b w two cells Allows interstitial flow Not Intercellular Tight Junctions joining of plasma membranes no fluid present Gap Junctions channels linking b w two cells Allow both to flow Glycocalyx chain or carbohydrates glycoprotein For interaction and signals Fuzzy barrier is b c of this Affinity vs Specificity Stronger it can bind stronger the affinity Ligand charge and shape is how strong it binds to ligand Need to have specificity to have affinity o Coffee and tea example Want to drink coffee more than tea so higher affinity for coffee have specificity for tea 02 04 2015 02 04 2015
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