E

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)