In the Cori cycle, when glucose is degraded by glycolysis to lactate in muscle,
ID: 495827 • Letter: I
Question
In the Cori cycle, when glucose is degraded by glycolysis to lactate in muscle, the lactate is excreted into the blood and returns to the liver where it is converted back into glucose by gluconeogenesis. For each enzyme below, identify whether it is involved in the glycolysis pathyway, gluconeogenesis pathway, both pathways or neither pathway. 1. triose phosphate isomerase 2. phosphoenolpyruvate carboxykinase 3. glucose-6-phosphate dehydrogenase 4. pyruvate carboxylase
1. triose phosphate isomerase O glycolysis O gluconeogenesis O both O neither 2. phosphoenolpyruvate carboxykinase O glycolysis O gluconeogenesis O both O neither 3. glucose-6-phosphate dehydrogenase O glycolysis O gluconeogenesis O both neither 5. phosphofructokinase- O glycolysis O gluconeogenesis O both O neither 6. phosphoglycerate kinase O glycolysis O gluconeogenesis O both neither 7. hexokinase O glycolysis O gluconeogenesis O both O neitherExplanation / Answer
1. Triose phosphate isomerase is key enzyme in glycolysis.
2.phosphoenolpyruvate carboxykinase is a lyase enzyme in the metabolic pathway of gluconeogenesis.
3.glucose 6 phosphate dehydrogenase is used in neither of these two. It is an enzyme in pentose phosphate pathway.
4.pyruvate carboxylase is again used in neither of these 2 reactions. It catalyses conversion of pyruvate into oxaloacetic acid OAA.