Term
| Stages 1-3 of intermediary metabolism |
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Definition
| 1. hydrolysis of complex molecules to their component building blocks, 2. conversion of building blocks to acetyl coa (or other simple intermediates), 3. oxidation of acetyl coa and oxidative phosphorylation |
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Term
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Definition
| metabolism of glucose to support energy production. intermediates in the pathway can be used to support other metabolic pathways. |
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Term
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Definition
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Term
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Definition
| glucose (and other carbs at intermediate steps) |
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Term
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Definition
| aerobic = pyruvate+2ATP+2NADH, anaerobic = lactate. |
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Term
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Definition
| in glycolysis. 2ATP, 1 for G>G6P, 1 for F6P>F16BP. |
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Term
| committing step in glycolysis |
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Definition
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Term
| glycolysis step where a single 6C molecule is cleaved into two 3C molecules |
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Definition
| F16BP> 2x glyceraldehyde 3-phosphate (each carries one phosphate from F16BP) |
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Term
| why does glycolysis only produce 2atp? |
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Definition
| it's actually 4, but 2atp are required for the reaction to proceed. 4-2=2. |
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Term
| when is NADH produced in glycolysis? |
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Definition
| glyceraldehyde3P>1,3bisphosphoglycerate |
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Term
| under anaerobic glycolysis conditions, NADH... |
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Definition
| is converted back to NAD+ in the Cori cycle. |
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Term
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Definition
| occurs when oxygen is low or mitochondria are low (RBCs, exercising muscle). Cori cycle = pyruvate>lactate in muscle, lactate to pyruvate in liver and then back to muscle. |
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Term
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Definition
| pyruvate enters mitochondria, is converted to acetyl coa and is used in the TCA cycle. |
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Term
| regulation of glycolysis, first of three steps |
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Definition
| hexokinase and glucokinase. H - in all tissues, low Km and Vmax. G - in liver and beta cells of pancreas. high Km and Vmax. (glucose>g6p) |
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Term
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Definition
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Term
| regulation of glucokinase |
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Definition
| stimulated by insulin, inhibited by glucagon |
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Term
| regulation of glycolysis, second of three steps |
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Definition
| (fructose6p>fructose16bisphosphate) PFK1 |
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Term
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Definition
| allosterically activated by high AMP, (allo) inhibited by high ATP, high citrate. in liver, inhibited by glucagon and stimulated by insulin. stimulated by fructose 2,6 bisphosphate. |
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Term
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Definition
| bifunctional enzyme: contains kinase and phosphatase (FBP2). is active when dephosphorylated and inactive (w/ FBP2 activated) when phosphorylated. favors the formation of Fru 2,6 bis P. |
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Term
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Definition
| glucagon actives cAMP which phosphorylates and inactivates PFK2. = decrease in Fru 2,6 bis P = reduction in glycolysis rate |
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Term
| regulation of third of three glycolysis steps (and regulation of the regulator) |
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Definition
| PEP>pyruvate = pyruvate kinase. stimulated by insulin and decreased by glucagon/epinephrine. |
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Term
| in liver glycolysis is catabolic/anabolic |
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Definition
| anabolic. in all other tissues, the pathway is used for energy generation and is considered catabolic. |
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Term
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Definition
| lactate accumulating in blood. caused by (myocardial) infarction, low oxygen tension in blood (lung disease), or impairment in oxidative phosphorylation. |
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Term
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Definition
| acidic pH = muscle cramps |
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Term
| pyruvate kinase deficiency |
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Definition
| common cause of hemolytic anemia. mature erythrocytes lack mitochondria, so are dependent on glycolysis for ATP production. without it, transporters in the RBC membranes stop functioning, so the membrane gets all spiny and the spleen eats the cell. autosomal recessive. also causes jaundice |
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Term
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Definition
| arsenate closely resembles inorganic phosphate and competes with it in enzymatic reactions. leads to inhibition of pyruvate dehydrogenase. is a competitive inhibitor of glyceraldehyde 3-phosphate dehydrogenase (which converts 1,3bisphosphoglycerate to 3-phosphoglycerate). = no ATP from that glycolysis step. {{brain is particularly affected}} |
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Term
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Definition
| >lactate (anaerobic metabolism), >alanine (links carb and AA metabolism), >OAA (gluconeogenesis), > Acetyl CoA (TCA) |
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Term
| oxidation of pyruvate: purpose and location |
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Definition
| formation of acetyl coa. mitochondrial matrix |
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Term
| substrates and products of oxidation of pyruvate; regulation. |
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Definition
| S - pyruvate. P - Acetyl Coa(, NADH); PDH. |
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Term
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Definition
| comprised of 3 enzymes and multiple cofactors. inhibited by Acetyl Coa, NADH, cAMP-mediated pathways. stimulated by insulin (dephosphorylation). |
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Term
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Definition
| most common cause of congenital lactic acidosis. brain is particularly sensitive. |
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Term
| purpose and location of TCA |
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Definition
| energy transfer from acetyl-coa to high energy compounds that drive ATP production. intermediates serve as precursors for many biosynthetic pathways. location - mitochondrial matrix |
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Term
| substrates and products of TCA / regulation |
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Definition
| S - acetyl coa. P - 3NADH, FADH2, GTP, 2CO2 / rates of glycolysis and TCA are integrated, so ATP and NADH inhibit TCA allosterically, citrate inhibits pfk1 in glycolysis, and the rate of pyruvate>acetylcoa affects TCA. |
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Term
| clinical relevance of TCA cycle |
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Definition
| many of the enzymes in the cycle are targets for genetic mutation. inborn errors. rare. |
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Term
| purpose and location of gluconeogenesis |
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Definition
| production of glucose from non-carb precursors; for glucose-requiring tissues (brain and nervous system, exercising skeletal muscle, RBCs, testes, renal medulla, embryonic tissues). location - liver and kidney - mitochondria and cytosol. |
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Term
| substrates and products of gluconeogenesis |
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Definition
| s - lactate OR glucogenic AAs OR glycerol. NOT FAT. p - glucose. |
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Term
| clinical relevance of gluconeogenesis |
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Definition
| inheritable defects result in hypoglycemia during fasts |
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Term
| what does gluconeogenesis require |
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Definition
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Term
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Definition
| *pyruvate>OAA>PEP. 1. pyruvate carboxylase, 2ATP. Takes place in liver mitochondria. 2. PEP carboxykinase (CK), 2GTP. Takes place in liver cytosol. *fructose16bp>fructose6p via fructose16bisphosphatase. Takes place in liver cytosol. *glucose6p>glucose via glucose6phosphatase. Takes place only in the endoplasmic reticulum of kidney. |
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Term
| energy requiring steps of gluconeogenesis (4) |
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Definition
| pyruvate>OAA>PEP (2). 2 3-phosphoglycerate to 2 1,3bisphosphoglycerate requires 2ATP. 2 1,3bisphosphoglycerate> 2 glyceraldehyde requires 2NADH. |
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Term
| regulation of gluconeogenesis |
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Definition
| inhibited by insulin, stimulated by glucagon and cAMP-mediated signaling. PFK2 and FBP2 (do opposite of what they do in glycolysis.) |
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Term
| regulation of pyruvate carboxylase |
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Definition
| allosterically activated by acetyl coa (high in fasted state) |
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Term
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Definition
| transcription of its mRNA is increased by glucagon and decreased by insulin |
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Term
| regulation of fructose 1,6-bisphosphatase |
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Definition
| inhibited by high AMP, fructose26bisphosphate, stimulated by high ATP. |
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Term
| why can't G6P leave the cell? |
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Definition
| the phosphate group has a negative charge, so it's no longer soluble through the cell membrane |
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Term
| pyruvate is oxidized/reduced to lactate? |
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Definition
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Term
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Definition
| acetyl coa donates 2C to the 4C oxaloacetate, which leads to a series of oxidation reactions |
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Term
| 3 regulated enzymes of TCA |
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Definition
| citrate synthase, isocitrate dehydrogenase ("pacemaker"), A-ketoglutarate dehydrogenase |
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Term
| gluconeogenesis and glycolysis are... |
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Definition
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Term
| protein kinase cascade is stimulated by |
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Definition
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Term
| gluconeogenesis is stimulated by... |
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Definition
| counter-regulatory hormones |
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Term
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Definition
| allosteric interactions, covalent (phosphorylation), enzyme levels, cellular compartmentalization, organ specific metabolism |
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Term
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Definition
| insufficiency of insulin, excess glucagon, elevated blood glucose |
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Term
| major consequence of a deficiency in the kinase in liver that synthesizes fructose26biphosphate? |
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Definition
| fructose16bisphosphatase activity will increase |
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