BCHM 3050 1st Edition Lecture 31 Outline of Last Lecture I Polysaccharides II ATP Adenosine triphosphate III Glycolysis Overview IV Step 1 V Step 2 VI Step 3 VII Step 4 VIII Step 5 IX Step 6 X Step 7 Outline of Current Lecture I Step 8 II Step 9 III Step 10 IV Pyruvate Kinase V Glucokinase vs Hexokinase VI Energy Investment VII Energy Payof VIII Regulation of Glycolysis IX Metabolic Fate of Pyruvate X Lactic Acid Fermentation XI Alcohol Fermentation XII Practice Questions Current Lecture I II III Step 8 a 3 converted to 2 position seems like a simple move from carbon 3 to carbon 2 but it involves an intermidiate 2 3 bisphosphoglycerate b Phosphoglyceratemutase belongs to the class of isomerases Step 9 a Dehydration reaction losing water b Do not want to consume too much fluoride because you can indirectly slow down glycolysis Step 10 These 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 V VI VII VIII IX a Alanine is a by product of the Krebs Cycle b All are allosteric act on a site diferent than the reaction site c Net gain of 2 ATP at the end of glycolysis but per reaction you only get 1 ATP because the rest is given of by heat d Delta G net free energy Pyruvate Kinase a The modification is phosphorylation b The levels of insulin and glucagon directs phosphorylation vs dephosphorylation c Direct covalent modification works on pyruvate kinase Glucokinase vs Hexokinase a Glucokinase is the sister enzyme to hexokinase b Glycogen alpha 1 4 c Glucokinase works in the liver and is a much higher pay in value d Km of the two enzymes is vastly diferent hexokinase is 10 times lower means that it has a better affinity e Hexokinase is the enzyme that usually carrier out glycolysis f Too much glucose use of glucokinase g Insulin is needed to activate glucokinase Energy Investment a Glucose is phosphorylated twice and cleaved in half to form two trioses b 2 ATP are consumed c Hexose is cleaved into 2 trioses Energy Payof a DHAP is converted to Gald 3P b Two Gald 3P is oxidized to pyruvate c 2 NADH and 4 ATP are produced d NADH is generated with dehydrogenase NAD is getting reduced to NADH e Dehydrogenase also carried out phosphorylation so technically it is also a kinase Regulation of Glycolysis a 3 enzymes are regulated during glycolysis b Too much glucose in the liver glucokinase will take presidence and be activated by insulin c Glucokinase happens in the liver and doesn t get inhibited by glucose 6phosphate d Hexokinase happens in the other tissues and does get inhibited by glucose 6phsophate e Insulin promotes glycolysis general rule and breakdown in the bloodstream f Glucagon inhibits glycolysis g Glucagon directly phosphorylates phosphoenolpyruvate only one to get directly phosphorylated Metabolic Fate of Pyruvate a By products are CO2 and water b Produce 2 NADHs X XI XII c 2 types of Anaerobic respiration homolactic fermentation and alcoholic fermentation d Homolactic fermentation pyruvate converted to lactate reversible ex Occurs with heavy exercise and is what causes the painful cramps e Alcoholic fermatation irreversible converts pyruvate to CO2 and ethanol f Aerobic respiration citric acid cycle Lactic Acid Fermentation a Lactate dehydrogenase suggests oxidation reduction is occurring b NADH gets recycled oxidized to NAD NAD goes to participate in glycolysis later on c Pyruvate get reduced to lactate d Important to have lactic acid fermentation is the absence of oxygen in order to produce NAD to be used in glycolysis Alcohol Fermentation a Pyruvate loses CO2 to form acetaldehyde 3C atoms 2C atom b Alcohol dehydrogenase recycles NADH and converts acetaldehyde to ethanol aldehyde group in acetaldehyde is reduced to OH group in ethanol c Too much NADH in the liver slows down metabolism Practice Questions a A high concentration of Glucose 6 P is inhibitory to which enzyme i Hexokinase b What are 3 mechanisms for altering the flux through the glycolytic pathway i Allosteric control of enzyme activity ii Genetic regulation of enzyme concentration iii Covalent modification of the enzyme c Phosphofructokinase the major flux controlling enzyme of glycolysis is allosterically inhibited by and activated by i ATP ADP
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