The activity of the glycolytic enzyme phosphofructokinase-1 is increased by which one of the following molecules?
ATP
Fructose-6-phosphate
Fructose-2,6-bisphosphate
Fructose-1,6-bisphosphate
Fructose-2,6-bisphosphate
In the glycolytic pathway ATP is synthesized by which one of the following methods?
Substrate-level phosphorylation
Photophosphorylation
Phosphorolysis
Oxidative phosphorylation
Substrate-level phosphorylation
Which one of the following is not involved in the reactions of glycolysis between glyceraldehyde-3-phosphate and 3-phosphoglycerate?
Generation of ATP.
Use of inorganic phosphate.
Catalysis by a kinase enzyme.
Oxidation of NADH.
The formation of a high en
Oxidation of NADH.
Which of the following identifies net production when 1 mol of glucose is converted to 2 mol of lactate? Assume that re-oxidation of NADH via the electron transport chain yields the equivalent of 3 ATP, and that re-oxidation of FADH2 yields 2 ATP.
2 mol o
2 mol of ATP.
Which of the following combinations correctly identifies net production when 1 mol of fructose 6-phosphate is converted to pyruvate during glycolysis? Assume that re-oxidation of NADH via the electron transport chain yields the equivalent of 3 ATP, and th
2 mol of NADH and 3 mol of ATP
Which of the following identifies net production when 1 mol of fructose-1,6-bisphosphate is converted to 2 mol of lactate? Assume that re-oxidation of NADH via the electron transport chain yields the equivalent of 3 ATP, and that re-oxidation of FADH2 yie
4 mol of ATP
Of the following pairs of metabolites and enzymes, which would be an example of product inhibition?
Fructose-2,6-bisphosphate and phosphofructokinase-2
Glucose-6-phosphate and hexokinase
Phosphoenolpyruvate and phosphofructokinase-1
Fructose-1,6-bisphosph
Glucose-6-phosphate and hexokinase
Which of the following is a method of directly regulating PFK-1?
Feed forward activation by phosphoenolpyruvate.
Feedback inhibition by fructose-2,6-bisphosphate.
Allosteric activation by ADP.
By its phosphorylation in response to glucagon signaling
Allosteric activation by ADP.
Which reaction or reactions in the scheme of glycolysis shown below will not proceed in the absence of NAD+?
A and C
D
E and H
B and F
E
D
Which of the following statements about the reaction catalyzed by hexokinase is FALSE?
Hexokinase undergoes a conformational change when glucose binds at the active site.
Hexokinase desolvates glucose to speed up the rate of the reaction.
Hexokinase is co
Hexokinase catalyses a substrate-level phosphorylation reaction
Which of the following is a high-energy intermediate produced in glycolysis?
Phosphocreatine
GAP
2-PG
F-1,6-BP
1,3-BPG
1,3-BPG
Which of the following statements about the oxidation reaction of glycolysis is TRUE?
Electrons are removed from NAD+.
The reaction halts in the absence of inorganic phosphate.
Some of the energy from the oxidation reaction is captured by the formation of
The reaction halts in the absence of inorganic phosphate.
Pyruvate has several metabolic fates depending on the cell, under aerobic or anaerobic conditions. Which one of the following is a metabolic fate for pyruvate?
oxidation to ethanol
reduction to lactate
decarboxylation to oxaloacetate
oxidative carboxylati
reduction to lactate
Which of the following is NOT a direct product of pyruvate metabolism?
Acetyl-CoA
Lactate
Oxaloacetate
Phosphoenolpyruvate
C and D
Phosphoenolpyruvate
Which one of the following enzymes catalyzes an "energy investment" reaction in glycolysis?
Hexokinase.
Phosphofructokinase-2.
Pyruvate kinase.
Phosphoglycerate kinase.
A and B.
Hexokinase
Which of the following statements is TRUE regarding the glycolytic pathway?
The pathway is regulated by allostery and product inhibition among other things.
The energy capture steps are all substrate-level phosphorylation reactions.
The balanced equation
The pathway is regulated by allostery and product inhibition among other things.
Which of the following is a reversible reaction under cellular conditions?
1,3-bisphosphoglycerate + ADP ------> 3-phosphoglycerate + ATP
Glucose-6-phosphate + H2O -----> Glucose + Pi
Phosphoenolpyruvate + ADP + H+ -----> Pyruvate + ATP
Fructose-6-phospha
1,3-bisphosphoglycerate + ADP ------> 3-phosphoglycerate + ATP
Which of the following represents the balanced equation of the energy payout/capture phase of glycloysis?
GAP + NAD+ + 2ADP + Pi ----> pyruvate + NADH + 2ATP + H+
GAP + 2NAD+ + 2ADP + 2Pi ---> pyruvate + 2NADH + 2ATP + 2H2O
GAP + 2NAD+ + 4ADP + 2Pi ---->
GAP + NAD+ + 2ADP + Pi ----> pyruvate + NADH + 2 ATP + H2O + H+
If pyruvate could not be converted to lactate in muscle cells during strenuous exercise, what would be the outcome?
The muscle cell would export pyruvate out of the cell.
The rate of gluconeogenesis will increase.
Glycolysis would be more efficient.
Glyco
Glycolysis would stop
Which of the following is a cofactor for the enzyme glyceraldehyde-3-phosphate dehydrogenase?
ADP
Pi
NAD+
ATP
NAD+
What is the most likely fate of pyruvate in mammalian muscle during very vigorous exercise?
Conversion to lactate via lactate dehydrogenase.
Conversion to oxaloacetate, to replenish citric acid cycle intermediates via anaplerotic reactions.
Conversion to
Conversion to lactate via lactate dehydrogenase.
Which of the following statements about lactate is TRUE?
Accumulation of lactate in muscle fibres during strenuous exercise causes acidotic damage.
Formation of lactate from pyruvate produces hydrogen ions.
Lactate transported to the liver is a gluconeoge
Lactate transported to the liver is a gluconeogenic precursor.
Which one of the following enzymes catalyzes a substrate-level phosphorylation reaction in the catabolism of glucose?
hexokinase
glyceraldehyde-3-phosphate dehydrogenase
pyruvate kinase
phosphofructokinase-1
pyruvate kinase
Which one of the following does NOT occur in the reactions of glycolysis between glucose and fructose-1,6-bisphosphate?
An isomerization.
Phosphoryl transfer.
Formation of a high energy intermediate.
Product inhibition of an enzyme.
Formation of a high energy intermediate.
What is the biochemical purpose for the production of lactate in muscle cells?
It decreases the pH of the muscle cell, thereby increasing release of oxygen from hemolglobin.
Its production enhances the activity of the citric acid cycle.
It is produced as
It is produced to reoxidize cytoplasmic NADH under anaerobic conditions
Glucose is converted to ______ in skeletal muscle under anaerobic conditions.
lactate
propionate
acetyl-CoA
ethanol and carbon dioxide
glycogen
lactate
Glycolysis produces a net of ______ ATP.
1
2
3
4
more than 4
2
Which of the following enzymes catalyzes the transfer of a phosphoryl group from ATP to glucose?
hexokinase
aldolase
phosphoglucose isomerase
glucose-6-phosphatase
phosphoglucose mutase
hexokinase
The enzymes that catalyze glycolysis are located in the
endoplasmic reticulum
cytosol
nucleus
mitochondrial matrix
inner mitochondrial membrane
cytosol
Which of the following enzymes forms a Schiff base as an intermediate in the mechanism of its reaction?
phosphoglucose isomerase
phosphoglucose mutase
aldolase
hexokinase
glucose-6-phosphatase
aldolase
Phosphofructokinase is allosterically inhibited by high concentrations of
glucose
ATP
pyruvate
fructose-6-phosphate
None of the above
ATP
In alcoholic fermentation, acetaldehyde is produced by
the decarboxylation of pyruvate
the carboxylation of pyruvate
the decarboxylation of lactate
the carboxylation of lactate
None of the above
the decarboxylation of pyruvate
Phosphomannose isomerase catalyzes the conversion of mannose-6-phosphate to
mannose-1-phosphate
fructose-6-phosphate
mannose
glucose-6-phosphate
galactose-6-phosphate
fructose-6-phosphate
The process by which ATP is formed from ADP in glycolysis is referred to as
photophosphorylation
oxidation
reduction
substrate-level phosphorylation
oxidative phosphorylation
substrate-level phosphorylation
Experimental evidence indicates that glyceraldehyde-3-phosphate dehydrogenase contains a critical ______ residue in its active site, as shown by its inactivation by iodoacetamide.
alanine
aspartate
cysteine
methionine
lysine
cysteine
Which is the net equation of glycolysis as it occurs in aerobic cells such as brain cells?
Glucose + 2 ADP + 2 Pi 2 lactate + 2 ATP + 2 H+
Glucose + 2 ADP + 2 Pi + 2 NAD+ 2 pyruvate + 2 ATP + 2 NADH + 4 H+
Glucose + 2 ADP + 2 Pi 2 CH3CH2OH + 2 CO2 + 2 ATP
Glucose + 2 ADP + 2 Pi + 2 NAD+ 2 pyruvate + 2 ATP + 2 NADH + 4 H+
In which of the following metabolic conversions is ATP "consumed" during glycolysis?
Glucose glucose-6-phosphate
Fructose-1,6-bisphosphate dihydroxyacetone phosphate + glyceraldehyde-3-phosphate
Glucose-6-phosphate fructose-6-phosphate
1,3-Bisphosphoglyce
Glucose glucose-6-phosphate
During glycolysis, the steps between glucose and formation of the triose phosphates
consume two NADH molecules
consume two ATP and two NADH molecules
produce two ATP and two NADH molecules
consume two ATP molecules
produce two ADP and two NAD+ molecules
consume two ATP molecules
In skeletal muscle cells, the NADH that is produced by glycolysis under anaerobic conditions (vigorous exercise) is regenerated to NAD+ by the conversion of:
phosphoenolpyruvate pyruvate
glyceraldehyde-3-phosphate 1,3-bisphosphoglycerate
acetaldehyde etha
pyruvate lactate
Which of the following metabolic conversions is considered to be the major control point of glycolysis?
pyruvate lactate
Fructose-1,6-bisphosphate dihydroxyacetone phosphate + glyceraldehyde-3-phosphate
Fructose-6-phosphate fructose-1,6-bisphosphate
2-pho
Fructose-6-phosphate fructose-1,6-bisphosphate
Galactosemia is a genetic disease characterized by the inability to convert
glycogen to glucose
galactose to glucose
glucose to galactose
sucrose to fructose and glucose
lactose to galactose and glucose
galactose to glucose
Which of the following compounds contains a "high-energy" bond and is used to produce ATP by substrate-level phosphorylation in glycolysis?
...
Which enzyme has an intermediate of the form presented?
enolase
aldolase
pyruvate decarboxylase
glyceraldehyde-3-phosphate dehydrogenase
lactate dehydrogenase
pyruvate decarboxylase
If glucose labelled at the C-1 position with 14C passes through glycolysis, on which carbon of pyruvate will the radiolabel be found?
1
2
3
It will be found on multiple carbons.
It's impossible to predict
3
Which of the following best explains why an enzyme hasn't evolved to catalyze the following reaction as the first step of glycolysis?
glucose + inorganic phosphate glucose-6-phosphate
The use of ATP is required for this step to serve as a regulatory contr
The large positive ?G�' of this reaction would need to be overcome by an exceedingly high [Pi].
Which enzyme catalyses a reaction with an enediol intermediate?
Phosphoglucomutase
Phosphoglucose isomerase
Phosphofructokinase
Aldolase
None of the above
Phosphoglucose isomerase
The reaction catalyzed by the enzyme aldolase has a ?G�' ? +23 kJ/mol. In muscle cells, the reaction proceeds in this same, forward direction. How can this occur?
The concentration of reactant(s) must be significant greater than product(s) in cells.
The e
The concentration of reactant(s) must be significant greater than product(s) in cells.
Conversion of galactose to glucose is accomplished by a(n)
kinase
hydrolase
isomerase
mutase
epimerase
epimerase
Methanol is highly toxic, not because of its own activity, but because it is converted metabolically into formaldehyde, which is the actual poison. What enzyme catalyses this conversion?
alcohol carboxylase
triose phosphate isomerase
alcohol dehydrogenase
alcohol dehydrogenase
Which of these reactions never occurs in a human being?
maltose 2 glucose
succinate + FAD fumarate + FADH2
-ketoglutarate + NAD+ + CoASH succinyl-CoA + NADH + H+ + CO2
glycogen(n) + phosphate glucose-1-P + glycogen(n-1)
pyruvate + NADH + H+ CO2 + ethanol
pyruvate + NADH + H+ CO2 + ethanol + NAD+
Which enzyme is involved in substrate level phosphorylation in glycolysis?
hexokinase
pyruvate kinase
glyceraldehyde-3phosphate dehydrogenase
aldolase
None of the above.
pyruvate kinase
Which of the following best describes the entry of mannose into glycolysis?
phosphorylated at C-1; UMP moiety transferred from UDP-glc; epimerized at C-4; released from UMP moiety on next transfer as G1P
phosphorylated at C-6; epimerized at C-2 to produce
phosphorylated at C-6; isomerized to produce F6P