UNE CHEM 1005 MIDTERM STUDY
GUIDE QUESTIONS AND ANSWERS
What enzyme is used by the gluconeogenic pathway but NOT in the glycolytic pathway? -
answer Phosphoenolpyruvate Carboxykinase PEPCK
Newborn screening results show a biotinidase deficiency in a 2 day old infant. The deficiency
impairs the infant's ability to reuse and recycle biotin. Due to the enzymatic deficiency, the
activity of what enzyme is likely impaired? - answer Pyruvate carboxylase
If unregulated, which of the following pairs of enzymes would represent a futile cycle? - answer
Fructose 1,6 -bisphosphate and phosphofructokinase-1
When cortisol binds to its receptor, which of the following events occur top stimulate
gluconeogenesis? - answer Enhanced transcription of regulatory enzymes
What compound allosterically activates pyruvate carboxylase - answer Acetyl-CoA
When the insulin to glucagon ratio is low, glycogenolysis is activated in the liver. Which of the
following is primary fate of the glucose 6-phosphate released under these conditions? - answer
Dephosphorylated and released into the blood to maintain blood glucose
What are the two major contributors to maintaining blood glucose levels during fasting? -
answer Hepatic glycogenolysis and gluconeogenesis
Pyruvate dehydrogenase complex is highly regulated. The enzyme that will be most active when
which of the following compounds is high? - answer Pyruvate
, A deficiency in thiamine can reduce the activity of the pyruvate dehydrogenase complex. Under
these conditions, you would expect a higher than normal blood concentration of which of the
following metabolites? - answer Pyruvate
A-ketoglutarate dehydrogenase is the enzyme responsible for one of the irreversible reactions in
the TCA cycle, What conversion does it catalyze? - answer A-ketoglutarate to succinyl-CoA
A 10-year old girl is swimming in a local competition. The intense exercise will increase
intracellular calcium levels which in turn will increase flux thru the TCA cycle by stimulating the
activity of all of the following enzymes EXCEPT - answer Succinate Thiokinase
TCA Cycle intermediates are always being removed for various reasons but the cycle does not
run out of intermediates and stop. This is because the TCA cycle can replenish intermediates
thru - answer Using anaplerotic reactions
A 10-year old boy is playing soccer and is sprinting after the ball. Under these anaerobic
conditions, glucose oxidation primarily results in an increase in - answer Lactate
Which of the following best describes the net effect of the 8 steps of the TCA cycle? - answer
This process completely oxidizes an acetyl group to carbon dioxide
Which of the following reactions is commonly used to replenish intermediates of the TCA cycle -
answer Glutamate to A-ketoglutarate
Within the red blood cell, NADPH is used - answer to re-reduce glutathione
In the non-oxidative portion of the pentose phosphate pathway, 2-carbon fragments of keto-
sugar can be transferred to other sugars to generate a larger sugar molecule. The reaction is
catalyzed by which of the following enzymes? - answer Transketolase
GUIDE QUESTIONS AND ANSWERS
What enzyme is used by the gluconeogenic pathway but NOT in the glycolytic pathway? -
answer Phosphoenolpyruvate Carboxykinase PEPCK
Newborn screening results show a biotinidase deficiency in a 2 day old infant. The deficiency
impairs the infant's ability to reuse and recycle biotin. Due to the enzymatic deficiency, the
activity of what enzyme is likely impaired? - answer Pyruvate carboxylase
If unregulated, which of the following pairs of enzymes would represent a futile cycle? - answer
Fructose 1,6 -bisphosphate and phosphofructokinase-1
When cortisol binds to its receptor, which of the following events occur top stimulate
gluconeogenesis? - answer Enhanced transcription of regulatory enzymes
What compound allosterically activates pyruvate carboxylase - answer Acetyl-CoA
When the insulin to glucagon ratio is low, glycogenolysis is activated in the liver. Which of the
following is primary fate of the glucose 6-phosphate released under these conditions? - answer
Dephosphorylated and released into the blood to maintain blood glucose
What are the two major contributors to maintaining blood glucose levels during fasting? -
answer Hepatic glycogenolysis and gluconeogenesis
Pyruvate dehydrogenase complex is highly regulated. The enzyme that will be most active when
which of the following compounds is high? - answer Pyruvate
, A deficiency in thiamine can reduce the activity of the pyruvate dehydrogenase complex. Under
these conditions, you would expect a higher than normal blood concentration of which of the
following metabolites? - answer Pyruvate
A-ketoglutarate dehydrogenase is the enzyme responsible for one of the irreversible reactions in
the TCA cycle, What conversion does it catalyze? - answer A-ketoglutarate to succinyl-CoA
A 10-year old girl is swimming in a local competition. The intense exercise will increase
intracellular calcium levels which in turn will increase flux thru the TCA cycle by stimulating the
activity of all of the following enzymes EXCEPT - answer Succinate Thiokinase
TCA Cycle intermediates are always being removed for various reasons but the cycle does not
run out of intermediates and stop. This is because the TCA cycle can replenish intermediates
thru - answer Using anaplerotic reactions
A 10-year old boy is playing soccer and is sprinting after the ball. Under these anaerobic
conditions, glucose oxidation primarily results in an increase in - answer Lactate
Which of the following best describes the net effect of the 8 steps of the TCA cycle? - answer
This process completely oxidizes an acetyl group to carbon dioxide
Which of the following reactions is commonly used to replenish intermediates of the TCA cycle -
answer Glutamate to A-ketoglutarate
Within the red blood cell, NADPH is used - answer to re-reduce glutathione
In the non-oxidative portion of the pentose phosphate pathway, 2-carbon fragments of keto-
sugar can be transferred to other sugars to generate a larger sugar molecule. The reaction is
catalyzed by which of the following enzymes? - answer Transketolase
