BCH451 EXAM 3 QUESTIONS AND ANSWERS WITH
COMPLETE SOLUTIONS VERIFIED
pyruvate carboxylase
converts pyruvate to oxaloacetate via carboxylation
requires Acetyl CoA as a positive effector
first step in gluconeogenesis
lactate to pyruvate
fermentation by lactate dehydrogenase converts lactate to pyruvate, yielding NADH
export of reducing equivalents (malate) unnecessary
makes use of lactate produced by glycolysis in erythrocytes or anaerobic muscle
Fructose-1,6-bisphosphatase
converts fructose 1,6-bisphosphate to fructose 6-phosphate
promotes essentially irreversible hydrolysis of C-1 phosphate (/not/ phosphorus group
transfer to ADP)
Mg+ dependent
,penultimate step in gluconeogenesis
malate dehydrogenase
reduces oxaloacetate to malate so it can be exported to cytosol (mitochondrial
membrane has no oxaloacetate transporter)
required NADH
reversible reaction in gluconeogenesis
malate
reoxidised in the cytosol to oxaloacetate in gluconeogenesis
Phosphoenolpyruvate carboxykinase
converts oxaloacetate to phosphoenolpyruvate
Mg+ dependent
requires GTP
reversible reaction in gluconeogenesis
phosphoenolpyruvate
(PEP) readily consumed in other reactions so concentration always remains relatively
low
, metabolic intermediate in glycolysis and gluconeogenesis
Glucose-6-phosphatase
hydrolysis (dephosphorylation) of phosphate ester in glucose-6-phosphate to produce
glucose
Mg+ dependent
active role in glycolysis and gluconeogenesis
glucogenic
Describes amino acids that can be converted into intermediates that feed into
gluconeogenesis; all amino acids except leucine and lysine
gluconeogenesis
occurs primarily in the liver to produce glucose for export to other tissues when
glycogen stores are exhausted and no dietary glucose is available
hexokinase
regulatory enzyme which catalysed the entry of glucose into the glycolytic pathway
phosphorylates glucose to generate glucose-6-phosphate
hexokinase II
high affinity for glucose
muscle enzyme that acts at or near its Vmax
COMPLETE SOLUTIONS VERIFIED
pyruvate carboxylase
converts pyruvate to oxaloacetate via carboxylation
requires Acetyl CoA as a positive effector
first step in gluconeogenesis
lactate to pyruvate
fermentation by lactate dehydrogenase converts lactate to pyruvate, yielding NADH
export of reducing equivalents (malate) unnecessary
makes use of lactate produced by glycolysis in erythrocytes or anaerobic muscle
Fructose-1,6-bisphosphatase
converts fructose 1,6-bisphosphate to fructose 6-phosphate
promotes essentially irreversible hydrolysis of C-1 phosphate (/not/ phosphorus group
transfer to ADP)
Mg+ dependent
,penultimate step in gluconeogenesis
malate dehydrogenase
reduces oxaloacetate to malate so it can be exported to cytosol (mitochondrial
membrane has no oxaloacetate transporter)
required NADH
reversible reaction in gluconeogenesis
malate
reoxidised in the cytosol to oxaloacetate in gluconeogenesis
Phosphoenolpyruvate carboxykinase
converts oxaloacetate to phosphoenolpyruvate
Mg+ dependent
requires GTP
reversible reaction in gluconeogenesis
phosphoenolpyruvate
(PEP) readily consumed in other reactions so concentration always remains relatively
low
, metabolic intermediate in glycolysis and gluconeogenesis
Glucose-6-phosphatase
hydrolysis (dephosphorylation) of phosphate ester in glucose-6-phosphate to produce
glucose
Mg+ dependent
active role in glycolysis and gluconeogenesis
glucogenic
Describes amino acids that can be converted into intermediates that feed into
gluconeogenesis; all amino acids except leucine and lysine
gluconeogenesis
occurs primarily in the liver to produce glucose for export to other tissues when
glycogen stores are exhausted and no dietary glucose is available
hexokinase
regulatory enzyme which catalysed the entry of glucose into the glycolytic pathway
phosphorylates glucose to generate glucose-6-phosphate
hexokinase II
high affinity for glucose
muscle enzyme that acts at or near its Vmax
