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MCAT Biology #5
Metabolism
| Term | Definition |
|---|---|
| Kinase | an enzyme that involves the transfer of a terminal phosphate group from ATP to another molecule |
| Hexokinase | enzyme that phosphorylates glucose into glucose 6-phosphate |
| Phosphoglucose isomerase | enzyme that isomerizes glucose 6-phosphate into fructose 6-phosphate |
| Phosphofructokinase | enzyme that phosphorylates fructose 6-phosphate into fructose 1,6-bisphosphate |
| Aldolase | enzyme that catalyzes the reverse aldol condensation of fructose 1,6-bisphosphate into DHAP and G-3P |
| DHAP stands for | dihydroxyacetonephosphate |
| G-3P stands for | glyceraldehyde 3-phosphate |
| Triose phosphate | enzyme that isomerizes DHAP into G-3P |
| Glyceraldehyde 3-dehydrogenase | enzyme that catalyzes the oxidation of glyceraldehyde 3-phosphate into 1,3-DPG |
| 1,3-DPG stands for | 1,3-diphosphoglyceraldehyde |
| Mixed anhydride linkage | a linkage involving an oxygen that is alpha to two keto functional groups |
| Phsophoglycerate kinase | enzyme that dephosphorylates 1,3-BPG into 3-PG |
| 3-PG stands for | 3-phosphoglycerate |
| Phosphoglyceromutase | enzyme that isomerizes 3-PG into 2-PG |
| 2-PG stands for | 2-phosphoglycerate |
| 2,3-BPG stands for | 2,3-bisphosphoglycerate |
| 2,3-BPG function | a molecule that binds in the middle of deoxy-hemoglobin and stabilizes, causing blood to release more oxygen |
| Enolase | enzyme that dehydrates 2-PG into PEP |
| PEP stands for | phosphoenolpyruvate |
| Pyruvate kinase | enzyme that catalyzes the transfer of a phosphoryl group from PEP to ADP and releases pyruvate and ATP |
| Net products of glycolysis | 2 net ATP and 2 NADH |
| Lactate dehydrogenase | enzyme that reduces pyruvate into lactate using NADH |
| Pyruvate decarboxylase | enzyme that decarboxylates pyruvate into acetaldehyde |
| Alcohol dehydrogenase | enzyme that reduces acetaldehyde into ethanol using NADH |
| Three reactions in glycolysis that are essentially reversible | rnx catalyzed by hexokinase, phosphofructokinase, pyruvate kinase |
| Components of sucrose | glucose and fructose |
| Components of maltose | glucose and glucose |
| Components of lactose | glucose and galactose |
| Where does Krebs cycle occur? | inside mitochondria |
| Where does glycolysis occur? In the cell’s cytosol | |
| Pyruvate dehydrogenase complex | a complex of enzymes that catalyzes the oxidative decarboxylation of pyruvate into acetyl CoA with the CoA factor |
| When is FAD the oxidizing agent in metabolism? | when dealing with a C-C bond |
| When is NAD the oxidizing agent in metabolism? | when dealing with a C-O bond |
| Thioester bond | an ester involving a carbonyl and a sulfur atom |
| Citrate synthetase | enzyme that catalyzes the combining of acetyl-CoA and oxaloacetate to form citrate |
| Aconitase | enzyme that converts citrate into cis-aconitate AND cis-aconitate into isocitrate |
| Isocitrate dehydrogenase | enzyme that oxidizes isocitrate into alpha-ketoglutarate via NAD |
| Alpha-ketoglutarate dehydrogenase complex | enzyme complex that catalizes an oxidative decarboxylation of alpha-ketoglutarate into succinyl-CoA with a CoA factor |
| Succinyl CoA synthetase | converts succinyl-CoA into succinate and generates one GTP atom |
| Succinate dehydrogenase | enzyme that oxidizes succinate into fumarate via FAD |
| Fumarase | enzyme that hydrates fumarate into malate |
| Malate dehydrogenase | enzyme that oxidizes malate into oxaloacetate via NAD |
| Net products of Krebs cycle | 2 ATP, 8 NADH, 2 FADH2 |
| NADH-Q reductase AKA | complex I |
| Succinate-Q reductase AKA | Complex II |
| Cytochrome reductase AKA | complex III |
| Cytochrome oxidase AKA | complex IV |
| Coenzyme Q AKA | ubiquinone |
| Oxidized form of Coenzyme Q | ubiquinone |
| Reduced form of Coenzyme Q | ubiquinol |
| Free-radical intermediate version of Coenzyme Q | semiquinone |
| Cytochrome | electron transporting proteins that contain a heme prosthetic group with an iron atom that alternates between oxidized and reduced states |
| 2,4-DNP is short for | 2,4-dinitrophenol |
| 2,4-DNP function | slightly acidic molecule that is capable of crossing the inner mitochondrial membrane that can dissociate to essentially transport protons back into the matrix, weakening the gradient |
| Glycerol phosphate shuttle of NADH yield | 2 ATP |
| Malate-aspartate shuttle of NADH yield | 3 ATP |
| Antimycin A function | a toxic antibiotic that blocks electorn flow between cytochromes b and c |
| Rotenone function | a toxic plant poison that inhibits electron transport within complex I |
| Ascorbate function | reduces cytochrome c and allows for electron flow from cytochrome c to oxygen |
| Cyanide function | inhibits complex IV |
| Azide function | inhibits complex IV |
| Carbon monoxide function | inhibits complex IV |
| Pentose phosphate pathway function | to generate reducing power in the form of NADPH and five carbon sugars such as ribose 5-phosphate |
| Glucose 6-phosphate dehydrogenase | enzyme that oxidizes the anomeric carbon on glucose 6-phosphate into a keto group, to form 6-phosphoglucono-d-lactone |
| Lactone AKA | cyclic ester |
| Lactonase | enzyme that hydrolyzes 6-Phosphoglucono-d-lactone into 6-phosphogluconate |
| 6-Phosphogluconate dehydrogenase | enzyme that catalyzes a oxidative decarboxylation of 6-phosphogluconate into ribulose 5-phosphate via NADP+ |
| Phosphopentose isomerase | isomerizes ribulose 5-phosphate into ribose 5-phosphate |
| NADP function | coenzyme involved in anabolic reactions |
| Transketolase | enzyme that catalyze the synthesis of xylulose-5-phosphate and erythrose 4-phosphate from G3P and fructose 6-phosphate |
| Phosphopentose epimerase | enzyme that converts xylulose-5-phosphate into ribulose 5-phosphate |
| Superoxide dismutase (SOD) | enzyme that catalyze the conversion of superoxide radical into hydrogen peroxide and oxygen |
| Catalase | enzyme that catalyzes the conversion of hydrogen peroxide into water |
| Cori cycle | the series of reactions involving glycolysis turning glucose into pyruvate, fermentation, turning pyruvate into lactate, and the liver turning lactate back into pyruvate and then into glucose again |
| Pyruvate carboxylate | enzyme that catalyzes the reaction from pyruvate back to PEP in gluconeogenesis |
| Anaplerotic reaction | reaction to fill up a need of a molecule |
| Futile cycle | a cycle of reactions in which we would run out of energy if we kept running the cycle |
| Fructose 1,6-diphosphate phosphatase | enzyme that catalyzes the reaction from fructose 1,6-bisphosphate to fructose 6-phosphate |
| Glucose 6-phosphate phosphatase | enzyme that catalyzes the reaction from glucose 6-phosphate to glucose |
| Three reactions that gluconeogenesis bypasses | the reactions involving the enzymes pyruvate carboxylate, fructose 1,6-bisphosphate phosphatase, and glucose 6-phosphate phosphatase |
| Glycerol phosphate dehydrogenase | enzyme that catalyzes the conversion of glycerol 3-phosphate into DHAP |
| Glycerol kinase | enzyme that phosphorylates glycerol |
| Acyl CoA synthetase | enzyme that activates fatty acids via 2 ATP-equivalent energy hydrolysis |
| Acyl-CoA dehydrogenase | enzyme that that oxidizes a fatty acid-CoA molecule into an enoyl-CoA molecule via FAD |
| Enoyl-CoA hydratase | enzyme that hydrates enoyl-CoA into L-Hydroxyacyl-CoA |
| L-3-hydroxyacyl-CoA dehydrogenase | enzyme that catalyzes the oxidation of L-Hydroxyacyl-CoA into Ketoacyl-CoA |
| Beta-ketothiolase | enzyme that catalyzes the thiolytic cleavage of ketoacyl-CoA into a shorter fatty acid-CoA and Acetyl-CoA |
| Transaminase | transfers the amino group of an amino acid to alpha-ketoglutarate to form an alpha keto acid and glutamate |
| Glutamate dehydrogenase | enzyme that that catalizes the oxidative deamination of glutamate into alpha-ketoglutarate and ammonia via NAD or NADP |
| Glucogenic amino acids | amino acids that will be degraded to pyruvate, alpha-ketoglutarate, succinyl-CoA, fumarate, and oxaloacetate. |
| Ketogenic amino acids | amino acids that will eventually give rise to ketone bodies |
| Carbamoyl phosphate synthetase | enzyme that synthesizes carbamoyl phosphate from carbon dioxide, ammonia and water |
| Carbamoyl transcarbamoylase | enzyme that catalyzes the transfer of the carbamoyl group from carbamoyl phosphate to ornithine to produce citrulline |