Glycolysis Flashcards

Matching

• Enzyme that catalyzes the formation of acetaldehyde and CO_2 from pyruvate, not present in animals: Pyruvate decarboxylase (C)
• Vitamin B1 component of coenzyme essential for electron sink development during pyruvate decarboxylation: Thiamine pyrophosphate (G)
• Glycolysis forms: ATP (H).
• Products of glycolysis include ATP, NADH, and: Pyruvate (L).
• Oxidizing agent in both aerobic and anaerobic glycolysis: NAD^+ (J).
• Inhibitor of enolase used in elucidating the glycolytic pathway: Fluoride ion (K).
• Genetic deficiency of transferase enzyme causing failure to thrive, mental retardation, and potential liver damage: Galactosemia (I).
• Major control point for glycolysis in muscle: Phosphofructokinase (E).
• Pathway that produces NADPH for lipid biosynthesis: Pentose phosphate (B).
• Enzyme participating in a regulatory substrate cycle with phosphofructokinase: Fructose-1,6-bisphosphatase (A).

Multiple Choice

• Glucose is converted to lactate in skeletal muscle under anaerobic conditions. (A)
• Aerobic glycolysis produces a net yield of 2 ATP. (B)
• Enzyme catalyzing phosphoryl group transfer from ATP to glucose: Hexokinase (A).
• Glycolysis enzymes are located in the cytosol. (C)
• Enzyme forming a Schiff base allowing aspartate-mediated cleavage: Aldolase (E).
• Phosphofructokinase is allosterically inhibited by ATP and activated by fructose-2,6-bisphosphate. (D)
• In alcoholic fermentation, acetaldehyde is produced by the decarboxylation of pyruvate. (A)
• Metabolism of mannose requires phosphomannose isomerase to produce fructose-6-phosphate for entry into glycolysis. (D)
• Glycolytic ATP synthesis occurs via substrate-level phosphorylation. (C)
• Glyceraldehyde-3-phosphate dehydrogenase contains a critical cysteine residue in its active site, inactivated by iodoacetamide. (C)
• Net equation for aerobic glycolysis:
  Glucose + 2 ADP + 2 Pi + 2 NAD^+ \rightarrow 2 pyruvate + 2 ATP + 2 NADH + 2 H_2O + 4 H^+ (B)
• ATP is required during glycolysis for:
  • fructose-6-phosphate → fructose-1,6-bisphosphate
  • glucose → glucose-6-phosphate (C)
• Products producing ATP:
  • II.
  • IV. (B)
• Reaction catalyzed by yeast alcohol dehydrogenase:
  • X = NADH + H^+
  • Y = NAD^+ (C)
• Steps between glucose and triose phosphates consume 2 ATP molecules. (B)
• In skeletal muscle cells, NADH generated from anaerobic glycolysis is oxidized during pyruvate → lactate. (D)
• Major control point of glycolysis: fructose-6-phosphate → fructose-1,6-bisphosphate. (D)
• Individuals with galactosemia cannot catabolize galactose via glycolysis. (A)
• Compound containing a “high-energy” bond used to produce ATP by substrate-level phosphorylation in glycolysis:
  C - CH2OPO3^{-2}
  \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ C=O
  \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ O^- (C)
• Enzyme with an intermediate of the form presented: pyruvate decarboxylase. (C)
• If glucose labeled at the C-1 position with ^{14}C passes through glycolysis, the radiolabel will be found on carbon 3 of pyruvate. (C)
• Why enzyme hasn't evolved to catalyze the reaction as the first step of glycolysis:
  • The use of ATP is important because it helps keep its concentration low.
  • Inorganic phosphate cannot be specifically placed on the carbon in the 6th position. (C)
• Glycolytic enzyme catalyzing a reaction with an enediolate intermediate: triose phosphate isomerase. (B)
• True regarding glycolysis: There is a net oxidation of substrate carbon atoms. (A)
• Reaction catalyzed by aldolase has a \Delta G' \approx +23 \frac{kJ}{mol}. Forward direction proceeds because concentration of reactants is significantly greater than products. (C)
• Conversion of galactose to glucose requires:
  • epimerase
  • uridine diphosphate
  • transferase (B)
• Methanol is converted metabolically into formaldehyde, which is catalyzed by alcohol dehydrogenase. (E)
• Reaction that does not occur in mammals: pyruvate + NADH + H+ → CO_2 + ethanol + NAD^+ (E)
• Enzyme involved in substrate-level phosphorylation in glycolysis: pyruvate kinase. (B)
• Entry of mannose into glycolysis: phosphorylated at C-6; isomerized to produce F6P. (E)
• Correct regarding the hexose monophosphate shunt:
  • Glyceraldehyde-3-phosphate is generated in the reaction.
  • The pathway requires a transaldolase. (D)
• Enzyme catalyzing the reaction shown below: hexokinase (HK). (A)
• Reaction type NOT used in glycolysis: All are used in glycolysis. (E)
• During reactions utilizing the enzymes, ATP is produced:
  • phosphoglycerate kinase (PGK)
  • pyruvate kinase (PK) (E)
• Control exhibited by phosphofructokinase (PFK):
  • It is allosterically inhibited by ATP and citrate.
  • It is allosterically activated by F2,6P. (D)
• ATP inhibits activity of phosphofructokinase (PFK) allosterically. (A)
• In which reaction above is ATP required?
• Glucose → glucose-6-phosphate (G6P) (B)
• Which reaction above is an oxidation reaction?
• Glycerol-3-phosphate (GAP) ® 1,3-Bisphosphoglycerate (BPG) (D)
• In which reaction above is at least 1 NADH formed?
• Glycerol-3-phosphate (GAP) ® 1,3-Bisphosphoglycerate (BPG) (C)
• The utilization of fructose in glycolysis in the liver bypasses phosphofructokinase (PFK) regulation. (D)