MCB 450 Exam 4 Review UPDATED
ACTUAL QUESTIONS AND CORRECT
ANSWERS
Gluconeogenesis - CORRECT ANSWER formation of glucose from noncarbohydrate sources
occurs in liver
sends out of liver to supply tissue and raise blood glucose
opposite of glycolysis
location of gluconeogenesis - CORRECT ANSWER mitochondria of liver cells
The unique enzymes of gluconeogenesis are used to circumvent specific irreversible steps of glycolysi
- CORRECT ANSWER pyruvate carboxylase and phosphoenolpyruvate carboxykinase
fructose-1.6-bisphosphatase
glucose-6-phosphatase
lactate to pyruvate - CORRECT ANSWER lactate dehydrogenase
pyruvate to oxaloacetate - CORRECT ANSWER pyruvate carboxylase
other sources for glycolosis - CORRECT ANSWER alanine, other AAs
glycerol by phosphorylation from fatty acids
pyruvate dehydrogenase complex - CORRECT ANSWER deactivated by glucagon by
phosphorylation
activated by insulin
converts pyruvate into Acetyl CoA for TCA cycle, inactive lets gluconeogenesis occur
, regulation of PDC - CORRECT ANSWER Fed state:
-Negative modifiers: ATP, Acetyl CoA, NADH
Fasting state:
-Positive modifiers: Pyruvate, ADP, NAD+
activators override inhibitors
Biotin use - CORRECT ANSWER active site of pyruvate carboxylate enzyme, dual function
enzyme to pick up CO2 and move it.
Arm grabs CO2 and swings to other section of a dimer enzyme to donate CO2 to pyruvate ->
oxaloacetate
Carboxykinase - CORRECT ANSWER removes CO2 and adds phosphate
Lys, Arg hold Oxygen atoms in ATP and COO- group. Withdrawing effect achieved with Mn2+ and
Mg2+.
Electron withdrawal snaps off CO2 and the oxyanion attacks ATP phosphate.
ADP and phosphorylated PEP released
Pyruvate kinase regulation - CORRECT ANSWER Phosphorylating deactivates
only Liver has glucagon control with PKA
Allosteric regulation by all cells; PEP activates, ATP or Acetyl CoA deactivates
Fructose-2,6-bisphosphatase - CORRECT ANSWER removes a phosphate group from
Fructose 2, 6 forming Fructose 6 Phosphate
dual acting enzyme;
PFK2 inactive by PKA due to phosphorylation
FBP2 activated by conformational change to perform gluconeogenesis
Glucose-6-phosphatase - CORRECT ANSWER in ER, dephosphorylates to glucose
Glucose exits liver into blood
Not present in muscle, G6P used for energy
ACTUAL QUESTIONS AND CORRECT
ANSWERS
Gluconeogenesis - CORRECT ANSWER formation of glucose from noncarbohydrate sources
occurs in liver
sends out of liver to supply tissue and raise blood glucose
opposite of glycolysis
location of gluconeogenesis - CORRECT ANSWER mitochondria of liver cells
The unique enzymes of gluconeogenesis are used to circumvent specific irreversible steps of glycolysi
- CORRECT ANSWER pyruvate carboxylase and phosphoenolpyruvate carboxykinase
fructose-1.6-bisphosphatase
glucose-6-phosphatase
lactate to pyruvate - CORRECT ANSWER lactate dehydrogenase
pyruvate to oxaloacetate - CORRECT ANSWER pyruvate carboxylase
other sources for glycolosis - CORRECT ANSWER alanine, other AAs
glycerol by phosphorylation from fatty acids
pyruvate dehydrogenase complex - CORRECT ANSWER deactivated by glucagon by
phosphorylation
activated by insulin
converts pyruvate into Acetyl CoA for TCA cycle, inactive lets gluconeogenesis occur
, regulation of PDC - CORRECT ANSWER Fed state:
-Negative modifiers: ATP, Acetyl CoA, NADH
Fasting state:
-Positive modifiers: Pyruvate, ADP, NAD+
activators override inhibitors
Biotin use - CORRECT ANSWER active site of pyruvate carboxylate enzyme, dual function
enzyme to pick up CO2 and move it.
Arm grabs CO2 and swings to other section of a dimer enzyme to donate CO2 to pyruvate ->
oxaloacetate
Carboxykinase - CORRECT ANSWER removes CO2 and adds phosphate
Lys, Arg hold Oxygen atoms in ATP and COO- group. Withdrawing effect achieved with Mn2+ and
Mg2+.
Electron withdrawal snaps off CO2 and the oxyanion attacks ATP phosphate.
ADP and phosphorylated PEP released
Pyruvate kinase regulation - CORRECT ANSWER Phosphorylating deactivates
only Liver has glucagon control with PKA
Allosteric regulation by all cells; PEP activates, ATP or Acetyl CoA deactivates
Fructose-2,6-bisphosphatase - CORRECT ANSWER removes a phosphate group from
Fructose 2, 6 forming Fructose 6 Phosphate
dual acting enzyme;
PFK2 inactive by PKA due to phosphorylation
FBP2 activated by conformational change to perform gluconeogenesis
Glucose-6-phosphatase - CORRECT ANSWER in ER, dephosphorylates to glucose
Glucose exits liver into blood
Not present in muscle, G6P used for energy
