PORTAGE LEARNING CHEM 210 MODULE 7 PROBLEM
SET QUESTIONS WITH ANSWERS AND EXPLANATIONS
Question 1.
A learner wants an example of isocitrate dehydrogenase. Which choice is best?
A. Water being added across the fumarate double bond.
B. The first carbon-carbon bond-forming step of the citric acid cycle.
C. The only citric acid cycle enzyme embedded in the inner mitochondrial membrane.
D. A citric acid cycle step generating the first CO2 and an NADH.
Correct Answer: D. A citric acid cycle step generating the first CO2 and an NADH.
Explanation: The underlying principle is that A citric acid cycle step generating the first
CO2 and an NADH. is a representative example of isocitrate dehydrogenase. Isocitrate
dehydrogenase oxidatively decarboxylates isocitrate to alpha-ketoglutarate and produces
NADH and CO2. The other options were drawn from related module concepts, but each
illustrates a different biochemical feature. Matching the defining feature to the example is
the most reliable way to solve this type of problem.
Question 2.
A student encounters this situation: A biochemical reaction with Delta G = -25 kJ/mol.
Which term should the student select?
A. aldolase
B. negative Delta G
C. alpha-ketoglutarate dehydrogenase
D. metabolic flux
Correct Answer: B. negative Delta G
Explanation: The correct interpretation is that the clue points to negative Delta G. A
reaction with a negative Delta G is thermodynamically favorable in the stated conditions
and can proceed spontaneously in the forward direction. The example given - A
biochemical reaction with Delta G = -25 kJ/mol. - is a direct application of that definition.
The alternative terms describe different structures, processes, or roles and therefore do
not fit the clue as closely.
Question 3.
A learner wants an example of net ATP from glycolysis. Which choice is best?
A. A balance sheet showing 4 ATP made minus 2 ATP used.
B. Counting ten reactions from glucose to pyruvate.
C. ATP being used by hexokinase and phosphofructokinase-1.
D. Two NAD+ molecules being reduced during glycolysis of one glucose.
Correct Answer: A. A balance sheet showing 4 ATP made minus 2 ATP used.
Explanation: Biochemically, A balance sheet showing 4 ATP made minus 2 ATP used. is a
representative example of net ATP from glycolysis. Glycolysis produces four ATP but
,consumes two, giving a net gain of two ATP per glucose. The other options were drawn
from related module concepts, but each illustrates a different biochemical feature.
Matching the defining feature to the example is the most reliable way to solve this type of
problem.
Question 4.
A student is distinguishing negative Delta G from metabolic flux. Which statement
correctly describes negative Delta G?
A. Flux is the rate at which material passes through a metabolic pathway.
B. Pyruvate dehydrogenase converts pyruvate to acetyl-CoA while producing NADH and
releasing carbon dioxide.
C. A reaction with a negative Delta G is thermodynamically favorable in the stated
conditions and can proceed spontaneously in the forward direction.
D. Isocitrate dehydrogenase oxidatively decarboxylates isocitrate to alpha-ketoglutarate
and produces NADH and CO2.
Correct Answer: C. A reaction with a negative Delta G is thermodynamically
favorable in the stated conditions and can proceed spontaneously in the forward
direction.
Explanation: For this module, remember that negative Delta G should be defined as
follows: A reaction with a negative Delta G is thermodynamically favorable in the stated
conditions and can proceed spontaneously in the forward direction. This differs from
metabolic flux, which is described by a separate set of properties. The distinction matters
because substituting one term for the other can change the predicted structure, location,
or biochemical outcome. The correct option therefore preserves the specific meaning of
negative Delta G.
Question 5.
Which example is most consistent with pyruvate dehydrogenase products?
A. Direct nucleotide triphosphate formation as succinyl-CoA becomes succinate.
B. One pyruvate yielding acetyl-CoA, CO2, and NADH.
C. Formation of a thioester between a fatty acid and coenzyme A.
D. ATP and citrate inhibiting an important glycolytic control enzyme.
Correct Answer: B. One pyruvate yielding acetyl-CoA, CO2, and NADH.
Explanation: Biochemically, One pyruvate yielding acetyl-CoA, CO2, and NADH. is a
representative example of pyruvate dehydrogenase products. Pyruvate dehydrogenase
converts pyruvate to acetyl-CoA while producing NADH and releasing carbon dioxide. The
other options were drawn from related module concepts, but each illustrates a different
biochemical feature. Matching the defining feature to the example is the most reliable way
to solve this type of problem.
,Question 6.
A student encounters this situation: A red blood cell converting glucose to pyruvate in the
cytoplasm. Which term should the student select?
A. glycolysis location
B. glycolytic payoff phase
C. glycolytic NADH production
D. net ATP from glycolysis
Correct Answer: A. glycolysis location
Explanation: This choice is correct because the clue points to glycolysis location.
Glycolysis occurs in the cytosol and does not require a mitochondrial enzyme system. The
example given - A red blood cell converting glucose to pyruvate in the cytoplasm. - is a
direct application of that definition. The alternative terms describe different structures,
processes, or roles and therefore do not fit the clue as closely.
Question 7.
Which option provides the strongest example of glyceraldehyde-3-phosphate
dehydrogenase?
A. A six-carbon glucose yielding two three-carbon pyruvates.
B. Fermentation maintaining glycolysis by restoring oxidized nicotinamide cofactor.
C. Formation of NADH and 1,3-bisphosphoglycerate from glyceraldehyde-3-phosphate.
D. A C16 acyl chain becoming C14 after one cycle while acetyl-CoA is released.
Correct Answer: C. Formation of NADH and 1,3-bisphosphoglycerate from
glyceraldehyde-3-phosphate.
Explanation: Biochemically, Formation of NADH and 1,3-bisphosphoglycerate from
glyceraldehyde-3-phosphate. is a representative example of glyceraldehyde-3-phosphate
dehydrogenase. Glyceraldehyde-3-phosphate dehydrogenase oxidizes
glyceraldehyde-3-phosphate while reducing NAD+ and adding inorganic phosphate. The
other options were drawn from related module concepts, but each illustrates a different
biochemical feature. Matching the defining feature to the example is the most reliable way
to solve this type of problem.
Question 8.
A student encounters this situation: Two NAD+ molecules being reduced during glycolysis
of one glucose. Which term should the student select?
A. net ATP from glycolysis
B. glycolytic investment phase
C. ten-step glycolysis
D. glycolytic NADH production
Correct Answer: D. glycolytic NADH production
Explanation: The correct interpretation is that the clue points to glycolytic NADH
production. Oxidation of glyceraldehyde-3-phosphate produces two NADH per glucose
, because two three-carbon molecules are processed. The example given - Two NAD+
molecules being reduced during glycolysis of one glucose. - is a direct application of that
definition. The alternative terms describe different structures, processes, or roles and
therefore do not fit the clue as closely.
Question 9.
Which situation most directly reflects glycolytic payoff phase?
A. A red blood cell converting glucose to pyruvate in the cytoplasm.
B. Four ATP and two NADH being produced after the cleavage stage.
C. A six-carbon glucose yielding two three-carbon pyruvates.
D. A balance sheet showing 4 ATP made minus 2 ATP used.
Correct Answer: B. Four ATP and two NADH being produced after the cleavage
stage.
Explanation: The underlying principle is that Four ATP and two NADH being produced
after the cleavage stage. is a representative example of glycolytic payoff phase. The later
phase of glycolysis generates ATP and NADH from two three-carbon intermediates formed
from one glucose. The other options were drawn from related module concepts, but each
illustrates a different biochemical feature. Matching the defining feature to the example is
the most reliable way to solve this type of problem.
Question 10.
A student is distinguishing pyruvate dehydrogenase location from metabolism. Which
statement correctly describes pyruvate dehydrogenase location?
A. Metabolism is the complete network of chemical reactions that transform matter and
energy in a living system.
B. Pyruvate dehydrogenase converts pyruvate to acetyl-CoA while producing NADH and
releasing carbon dioxide.
C. The pyruvate dehydrogenase complex operates in the mitochondrial matrix in
eukaryotic cells.
D. The early phase of glycolysis consumes two ATP per glucose to phosphorylate and
prepare the six-carbon sugar for cleavage.
Correct Answer: C. The pyruvate dehydrogenase complex operates in the
mitochondrial matrix in eukaryotic cells.
Explanation: For this module, remember that pyruvate dehydrogenase location should be
defined as follows: The pyruvate dehydrogenase complex operates in the mitochondrial
matrix in eukaryotic cells. This differs from metabolism, which is described by a separate
set of properties. The distinction matters because substituting one term for the other can
change the predicted structure, location, or biochemical outcome. The correct option
therefore preserves the specific meaning of pyruvate dehydrogenase location.
SET QUESTIONS WITH ANSWERS AND EXPLANATIONS
Question 1.
A learner wants an example of isocitrate dehydrogenase. Which choice is best?
A. Water being added across the fumarate double bond.
B. The first carbon-carbon bond-forming step of the citric acid cycle.
C. The only citric acid cycle enzyme embedded in the inner mitochondrial membrane.
D. A citric acid cycle step generating the first CO2 and an NADH.
Correct Answer: D. A citric acid cycle step generating the first CO2 and an NADH.
Explanation: The underlying principle is that A citric acid cycle step generating the first
CO2 and an NADH. is a representative example of isocitrate dehydrogenase. Isocitrate
dehydrogenase oxidatively decarboxylates isocitrate to alpha-ketoglutarate and produces
NADH and CO2. The other options were drawn from related module concepts, but each
illustrates a different biochemical feature. Matching the defining feature to the example is
the most reliable way to solve this type of problem.
Question 2.
A student encounters this situation: A biochemical reaction with Delta G = -25 kJ/mol.
Which term should the student select?
A. aldolase
B. negative Delta G
C. alpha-ketoglutarate dehydrogenase
D. metabolic flux
Correct Answer: B. negative Delta G
Explanation: The correct interpretation is that the clue points to negative Delta G. A
reaction with a negative Delta G is thermodynamically favorable in the stated conditions
and can proceed spontaneously in the forward direction. The example given - A
biochemical reaction with Delta G = -25 kJ/mol. - is a direct application of that definition.
The alternative terms describe different structures, processes, or roles and therefore do
not fit the clue as closely.
Question 3.
A learner wants an example of net ATP from glycolysis. Which choice is best?
A. A balance sheet showing 4 ATP made minus 2 ATP used.
B. Counting ten reactions from glucose to pyruvate.
C. ATP being used by hexokinase and phosphofructokinase-1.
D. Two NAD+ molecules being reduced during glycolysis of one glucose.
Correct Answer: A. A balance sheet showing 4 ATP made minus 2 ATP used.
Explanation: Biochemically, A balance sheet showing 4 ATP made minus 2 ATP used. is a
representative example of net ATP from glycolysis. Glycolysis produces four ATP but
,consumes two, giving a net gain of two ATP per glucose. The other options were drawn
from related module concepts, but each illustrates a different biochemical feature.
Matching the defining feature to the example is the most reliable way to solve this type of
problem.
Question 4.
A student is distinguishing negative Delta G from metabolic flux. Which statement
correctly describes negative Delta G?
A. Flux is the rate at which material passes through a metabolic pathway.
B. Pyruvate dehydrogenase converts pyruvate to acetyl-CoA while producing NADH and
releasing carbon dioxide.
C. A reaction with a negative Delta G is thermodynamically favorable in the stated
conditions and can proceed spontaneously in the forward direction.
D. Isocitrate dehydrogenase oxidatively decarboxylates isocitrate to alpha-ketoglutarate
and produces NADH and CO2.
Correct Answer: C. A reaction with a negative Delta G is thermodynamically
favorable in the stated conditions and can proceed spontaneously in the forward
direction.
Explanation: For this module, remember that negative Delta G should be defined as
follows: A reaction with a negative Delta G is thermodynamically favorable in the stated
conditions and can proceed spontaneously in the forward direction. This differs from
metabolic flux, which is described by a separate set of properties. The distinction matters
because substituting one term for the other can change the predicted structure, location,
or biochemical outcome. The correct option therefore preserves the specific meaning of
negative Delta G.
Question 5.
Which example is most consistent with pyruvate dehydrogenase products?
A. Direct nucleotide triphosphate formation as succinyl-CoA becomes succinate.
B. One pyruvate yielding acetyl-CoA, CO2, and NADH.
C. Formation of a thioester between a fatty acid and coenzyme A.
D. ATP and citrate inhibiting an important glycolytic control enzyme.
Correct Answer: B. One pyruvate yielding acetyl-CoA, CO2, and NADH.
Explanation: Biochemically, One pyruvate yielding acetyl-CoA, CO2, and NADH. is a
representative example of pyruvate dehydrogenase products. Pyruvate dehydrogenase
converts pyruvate to acetyl-CoA while producing NADH and releasing carbon dioxide. The
other options were drawn from related module concepts, but each illustrates a different
biochemical feature. Matching the defining feature to the example is the most reliable way
to solve this type of problem.
,Question 6.
A student encounters this situation: A red blood cell converting glucose to pyruvate in the
cytoplasm. Which term should the student select?
A. glycolysis location
B. glycolytic payoff phase
C. glycolytic NADH production
D. net ATP from glycolysis
Correct Answer: A. glycolysis location
Explanation: This choice is correct because the clue points to glycolysis location.
Glycolysis occurs in the cytosol and does not require a mitochondrial enzyme system. The
example given - A red blood cell converting glucose to pyruvate in the cytoplasm. - is a
direct application of that definition. The alternative terms describe different structures,
processes, or roles and therefore do not fit the clue as closely.
Question 7.
Which option provides the strongest example of glyceraldehyde-3-phosphate
dehydrogenase?
A. A six-carbon glucose yielding two three-carbon pyruvates.
B. Fermentation maintaining glycolysis by restoring oxidized nicotinamide cofactor.
C. Formation of NADH and 1,3-bisphosphoglycerate from glyceraldehyde-3-phosphate.
D. A C16 acyl chain becoming C14 after one cycle while acetyl-CoA is released.
Correct Answer: C. Formation of NADH and 1,3-bisphosphoglycerate from
glyceraldehyde-3-phosphate.
Explanation: Biochemically, Formation of NADH and 1,3-bisphosphoglycerate from
glyceraldehyde-3-phosphate. is a representative example of glyceraldehyde-3-phosphate
dehydrogenase. Glyceraldehyde-3-phosphate dehydrogenase oxidizes
glyceraldehyde-3-phosphate while reducing NAD+ and adding inorganic phosphate. The
other options were drawn from related module concepts, but each illustrates a different
biochemical feature. Matching the defining feature to the example is the most reliable way
to solve this type of problem.
Question 8.
A student encounters this situation: Two NAD+ molecules being reduced during glycolysis
of one glucose. Which term should the student select?
A. net ATP from glycolysis
B. glycolytic investment phase
C. ten-step glycolysis
D. glycolytic NADH production
Correct Answer: D. glycolytic NADH production
Explanation: The correct interpretation is that the clue points to glycolytic NADH
production. Oxidation of glyceraldehyde-3-phosphate produces two NADH per glucose
, because two three-carbon molecules are processed. The example given - Two NAD+
molecules being reduced during glycolysis of one glucose. - is a direct application of that
definition. The alternative terms describe different structures, processes, or roles and
therefore do not fit the clue as closely.
Question 9.
Which situation most directly reflects glycolytic payoff phase?
A. A red blood cell converting glucose to pyruvate in the cytoplasm.
B. Four ATP and two NADH being produced after the cleavage stage.
C. A six-carbon glucose yielding two three-carbon pyruvates.
D. A balance sheet showing 4 ATP made minus 2 ATP used.
Correct Answer: B. Four ATP and two NADH being produced after the cleavage
stage.
Explanation: The underlying principle is that Four ATP and two NADH being produced
after the cleavage stage. is a representative example of glycolytic payoff phase. The later
phase of glycolysis generates ATP and NADH from two three-carbon intermediates formed
from one glucose. The other options were drawn from related module concepts, but each
illustrates a different biochemical feature. Matching the defining feature to the example is
the most reliable way to solve this type of problem.
Question 10.
A student is distinguishing pyruvate dehydrogenase location from metabolism. Which
statement correctly describes pyruvate dehydrogenase location?
A. Metabolism is the complete network of chemical reactions that transform matter and
energy in a living system.
B. Pyruvate dehydrogenase converts pyruvate to acetyl-CoA while producing NADH and
releasing carbon dioxide.
C. The pyruvate dehydrogenase complex operates in the mitochondrial matrix in
eukaryotic cells.
D. The early phase of glycolysis consumes two ATP per glucose to phosphorylate and
prepare the six-carbon sugar for cleavage.
Correct Answer: C. The pyruvate dehydrogenase complex operates in the
mitochondrial matrix in eukaryotic cells.
Explanation: For this module, remember that pyruvate dehydrogenase location should be
defined as follows: The pyruvate dehydrogenase complex operates in the mitochondrial
matrix in eukaryotic cells. This differs from metabolism, which is described by a separate
set of properties. The distinction matters because substituting one term for the other can
change the predicted structure, location, or biochemical outcome. The correct option
therefore preserves the specific meaning of pyruvate dehydrogenase location.
