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11 Cards in this Set
- Front
- Back
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What are the digestible and non-digestible carbohydrates?
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Digestible:
-starch, glycogen, lactose, sucrose, glycolipids, glucose, fructose Non-digestible: -cellulose, inulin, pectin |
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What is used to break down oligosaccharides and polysaccharides?
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Endoglycosidases:
Amylase - polysaccharides -salivary and pancreatic Oligosaccharidase - oligosaccharides -intestine disaccharidases - disaccharide -sucrase -isomaltase -lactase -maltase -intestine |
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What does Salivary amylase do?
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also called alpha amylase or ptyalin
converts starch and glycogen into alpha dextrin in the mouth activated by Cl- and Ca+ pH range = 6.6 - 8.0 action till bolus reaches gastric juice HCl may hydrolyze sucrose |
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What are important features of digestion by oligosaccharidases and disaccharidases?
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responsible for final conversion of carbohydrates into monosaccharides
disaccharidases are bound to the gut epithelium protruding into the intestinal lumen disaccharidase may cleave beta glycosidic linkages intestinal amylase (glucoamylase): dextrin --> glucose + isomaltose Disaccharidases: Maltase-Maltose/Maltotriose --> glucose Isomaltase-Isomaltose --> glucose Lactase-Lactose --> glucose + galactose Sucrase-Sucrose --> glucose + fructose |
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What do Glut 2 and Glut 4 do?
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Glut 2 - intestinal cells, liver, beta cells of the pancreas:
-facilitated diffusion from intestinal cell to blood -acts as glucose sensor in beta cells of pancrease, monitors glucose levels to adjust rate of insulin release Glut 4 - muscles, adipose (INSULIN MEDIATED) -from blood to peripheral tissues |
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What does pancreatic amylase do?
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also called intestinal amylase (glucoamylase) --> alpha 1,4 of dextrins
converts alpha dextrin into maltose, maltotriose, isomaltose, limit dextrins, and glucose |
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What is the biological importance of glycolysis?
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anaerobic - provide energy in anoxic/hypoxic episodes - skeletal muscle during exercise
aerobic - heart muscles - poor survival under ischemic conditions hemolytic anemia - pyruvate kinase/hexokinase deficiency |
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How is glucose uptaked and phosphoyrlated?
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-uptake in liver by glucose transporters (GLUT)
phosphorylation by: Hexokinase: -wide tissue distribution -high affinity for the substrate -allosterically regulated Glucokinase: -liver and beta cells of pancreas -low affinity for substrate |
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What are the regulations of glycolysis?
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Step 1:
-hexokinase and glucokinase convert 1 ATP to ADP (-1 ATP) Step 3: -PFK converts 1 ATP to ADP (-1 ATP) Step 10: -Pyruvate kinase converts 2 ADP to 2 ATP (+2 ATP) Step 6 (not rate limiting): -produces NADH because this produces 6 ATP in ETC Insulin enhances glycolysis Covalent modification: -phosphorylation and dephosphorylation of key enzymes Allosteric regulation |
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What is the Rapaport Leubering Shut (RLS)?
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RBCs are dependent on glucose for fuel
RBCs lack mitochondria --> anaerobic glycolysis for energy Some glucose is produced by making 2,3 BPG as a intermediate bypassing glycolysis: -stabilizes the deoxy form of Hb -high BPG content shifts oxygen dissociation curve to the right -favors unloading of oxygen to tissues -high 2,3 BPG in high altitude and fetus |
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What is the Fluoride Bulb?
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Fluoride is an inhibitor of glycolysis by inhibiting enolase
bulb is used for collection of blood for glucose estimation |
