Term
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Definition
| the process where a molecule of glucose is degraded in a series of enzyme-catalyzed reactions to yield two molecules of the three-carbon compound pyruvate |
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Term
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Definition
| the anaerobic degradation of glucose or other organic nutrients to obtain energy conserved as ATP |
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Term
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Definition
| pyruvate's reduction to lactate |
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Term
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Definition
| low oxygen conditions that vigorously contracting skeletal muscles must function under; NADH cannot be reoxidized to NAD+, but NAD+ is required as an electron acceptor for the further oxidation of pyruvate |
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Term
| ethanol (alcohol) fermentation |
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Definition
| in plant tissues & in certain invertebrates, protists, & microorganisms (such as brewer's or baker's yeast), pyruvate is converted under hypoxic or anaerobic conditions to ethanol & CO2 |
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Term
| 3 functions of the phosphoryl groups in the intermediates of glycolysis |
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Definition
1. because the plasma membrane generally lacks transporters or phosphorylated sugars, the phosphorylated glycolytic intermediates cannot leave the cell
2. phosphoryl groups are essential components in the enzymatic conservation of metabolic energy
3. binding energy resulting from the binding of phosphate groups to the active sites of enzymes lowers the activation energy & increases the specificity of the enzymatic reactions |
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Term
| Is the reaction catalyzed by hexokinase reversible or irreversible? |
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Definition
| irreversible under intracellular conditions |
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Term
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Definition
| two or more enzymes that catalyze the same reaction but are encoded by different genes |
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Term
| phosphofructokinase-1 (PFK-1) |
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Definition
| in one of the priming reactions of glycolysis, it catalyzes the transfer of a phosphoryl group from ATP to fructose 6-phosphate to yield fructose 1,6-biphosphate |
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Term
| phosphohexose isomerase (phosphoglucose isomerase) |
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Definition
| the enzyme that catalyzes the reversible isomerization of glucose 6-phosphate (an aldose) to fructose 6-phosphate (a ketose) |
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Term
| fructose 1,6-biphosphate aldolase (aldolase) |
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Definition
| the enzyme that catalyzes a reversible aldol condensation |
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Term
| 2 triose phosphates that fructose 1,6-biphosphate is cleaved into |
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Definition
1. glyceraldehyde 3-phosphate (an aldose)
2. dihydroxyacetone phosphate (a ketose) |
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Term
| triose phosphate isomerase |
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Definition
| the enzyme that rapidly & reversibly converts dihydroxyacetone phosphate to glyceraldehyde 3-phosphate |
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Term
| glyceraldehyde 3-phosphate dehydrogenase |
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Definition
| catalyzes the oxidation of glyceraldehyde 3-phosphate to 1,3-biphosphoglycerate |
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Term
| Does an acyl phosphate (a type of anhydride) have a very high or very low standard free energy of hydrolysis? |
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Definition
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Term
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Definition
| the enzyme that transfers the high-energy phosphoryl group from the carboxyl group of 1,3-biphosphoglycerate to ADP to form ATP & 3-phosphoglycerate |
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Term
| What is different about substrate-level phosphorylation & respiration-lined phosphorylation? |
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Definition
| substrate-level phosphorylation = the formation of ATP by phosphoryl group transfer from a substrate (such as 1,3-biphosphoglycerate) |
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Term
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Definition
| the enzyme that catalyzes a reversible shift of the phosphoryl group between C-2 & C-3 of glycerate; Mg2+ is essential for this reaction |
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Term
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Definition
| in a glycolytic reaction that generates a compound with high phosphoryl group transfer potential, it promotes reversible removal of a molecule of water from 2-phosphoglycerate to yield phosphoenolpyruvate (PEP) |
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Term
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Definition
| catalyzes the last step in glycolysis in which the phosphoryl group from phosphoenolpyruvate is transferred to ADP; also requires K+ and either Mg2+ or Mn2+ |
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Term
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Definition
| in untreated type 1 diabetes, overproduction of acetoacetate & beta-hydroxybutyrate leads to their accumulation in the blood & consequently lowers blood pH |
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Term
| When animal tissues cannot be supplied with sufficient oxygen to support aerobic oxidation of the pyruvate & NADH produced in glycolysis, how is NAD+ regenerated from NADH? |
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Definition
| by the reduction of pyruvate to lactate |
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Term
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Definition
| catalyzes the reduction of pyruvate; forms the L isomer of lactate at pH 7 |
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Term
| What 2 things do NOT happen in fermentation, despite it extracting energy? |
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Definition
1. does not consume oxygen
2. does not change the concentrations of NAD+ or NADH |
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Term
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Definition
| catalyzes the irreversible reaction in which pyruvate is decarboxylated |
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Term
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Definition
| reduces acetaldehyde to ethanol; uses the reducing power furnished by NADH derived from the dehydrogenation of glyceraldehyde 3-phosphate |
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Term
| thiamine pyrophosphate (TPP) |
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Definition
| provided by the pyruvate decarboxylase reaction; a coenzyme derived from vitamin B1 |
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Term
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Definition
| a pathway that converts pyruvate & related three- & four-carbon compounds to glucose |
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Term
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Definition
| a mitochondrial enzyme that requires the coenzyme biotin & converts the pyruvate to oxaloacetate |
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Term
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Definition
| a mitochondrial molecule that reduces the oxaloacetate (formed from pyruvate) to malate to allow for export to the cytosol (because the mitochondrial membrane has no transporter for oxaloacetate); uses NADH |
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Term
| phosphoenolpyruvate carboxykinase |
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Definition
| converts the oxaloacetate to PEP |
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Term
| fructose 1,6-biphosphatase (FBPase-1) |
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Definition
| an Mg2+-dependent enzyme that catalyzes the generation of fructose 6-phosphate from fructose 1,6-biphosphate (this reaction is highly exergonic & irreversible in intact cells); promotes the essentially irreversible hydrolysis of the C-1 phosphate |
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Term
| Does the reaction catalyzed by glucose 6-phosphatase require synthesis of ATP? |
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Definition
| no! it is a simple hydrolysis of a phosphate ester |
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Term
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Definition
| amino acids that can undergo net conversion to glucose |
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Term
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Definition
| a truncated version of gluconeogenesis carries out by adipocytes; the conversion of pyruvate to dihydroxyacetone phosphate via the early reactions of gluconeogenesis, followed by reduction of the dihydroxyacetone phosphate to glycerol phosphate |
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Term
| pentose phosphate pathway (phosphogluconate pathway) (hexose monophosphate pathway) |
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Definition
| the oxidation of glucose 6-phosphate to pentose phosphates |
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Term
| glucose 6-phosphate dehydrogenase (G6PD) |
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Definition
| allows for the oxidation of glucose 6-phosphate in the first reaction of the pentose phosphate pathway; forms 6-phosphoglucono-delta-lactone (an intramolecular ester) |
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Term
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Definition
| converts ribulose 5-phosphate to its aldose isomer ribose 5-phosphate |
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Term
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Definition
| catalyzes the transfer of a two-carbon fragment from a ketose donor to an aldose acceptor |
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Term
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Definition
| catalyzes a reaction similar to the aldolase reaction of glycolysis: a three-carbon fragment is removed from sedoheptulose 7-phosphate & condensed with glyceraldehyde 3-phosphate to form fructose 6-phosphate & the tetrose erythrose 4-phosphate |
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