BIOMG 3300 Unit 11 Questions with Correct Answers
Why is gluconeogenesis important? Correct Answer-Some tissues
depend almost completely on glucose for energy, but the stores of
glucose are not always sufficient to last in between meals
Where does gluconeogensis mainly take place in? Correct Answer-The
liver
Name 3 noncarbodydrate precursors to glucose? Correct Answer--
Lactate
-Amino acids
-Glycerol
Which steps of glycolysis are essentially irreversible and must be
bypassed? Correct Answer--glucose --> glucose 6-phosphate
-fructose 6-phosphate --> fructose 1,6-bisphosphate
-phosphoenolpyruvate --> pyruvate
Know structures and be able to write out the first of two reactions
converting Pyruvate to PEP Correct Answer-1 Pyruvate + HCO3- +
ATP --> Oxaloacetate + ADP + Pi
What enzyme catalyzes the first bypass of gluconeogenesis? Correct
Answer-Pyruvate carboxylase
, Know structures and be able to write out the second of two reactions
converting Pyruvate to PEP Correct Answer-Oxaloacetate + GTP -->
PEP + GDP + CO2
Why is pyruvate carboxylated to oxaloacetate and then decarboxylated
to PEP? Correct Answer-Carboxylation activates pyruvate to allow it to
be decarboxylated to PEP
What cofactor is used by pyruvate carboxylase and what is its function?
What is the role of ATP? Correct Answer-Biotin, transfers an activated
CO2 group from bicarbonate to one active site to another, allowing it to
be added to pyruvate
ATP activates CO2 for addition to biotin and pyruvate
Why, in the absence of lactate, is oxaloacetate converted to malate in the
mitochondrion and then converted back to oxaloacetate in the
cytoplasm? Correct Answer-1) there is no transport protein for
oxaloacetate
2)Necessary in transport of NADH-->NAD+ out of mitochondria where
it can be re-reduced
Why, in the presence of lactate, is oxaloacetate not converted to malate
then reconverted to oxaloacetate? Why does is the lactate--> pyruvate
reaction for favorable> Correct Answer-Because oxidation of lactate to
oxaloacetate produces NADH in the cytoplasm, so there's no need to
shuttle it out of the mitochondria. saves energy
Why is gluconeogenesis important? Correct Answer-Some tissues
depend almost completely on glucose for energy, but the stores of
glucose are not always sufficient to last in between meals
Where does gluconeogensis mainly take place in? Correct Answer-The
liver
Name 3 noncarbodydrate precursors to glucose? Correct Answer--
Lactate
-Amino acids
-Glycerol
Which steps of glycolysis are essentially irreversible and must be
bypassed? Correct Answer--glucose --> glucose 6-phosphate
-fructose 6-phosphate --> fructose 1,6-bisphosphate
-phosphoenolpyruvate --> pyruvate
Know structures and be able to write out the first of two reactions
converting Pyruvate to PEP Correct Answer-1 Pyruvate + HCO3- +
ATP --> Oxaloacetate + ADP + Pi
What enzyme catalyzes the first bypass of gluconeogenesis? Correct
Answer-Pyruvate carboxylase
, Know structures and be able to write out the second of two reactions
converting Pyruvate to PEP Correct Answer-Oxaloacetate + GTP -->
PEP + GDP + CO2
Why is pyruvate carboxylated to oxaloacetate and then decarboxylated
to PEP? Correct Answer-Carboxylation activates pyruvate to allow it to
be decarboxylated to PEP
What cofactor is used by pyruvate carboxylase and what is its function?
What is the role of ATP? Correct Answer-Biotin, transfers an activated
CO2 group from bicarbonate to one active site to another, allowing it to
be added to pyruvate
ATP activates CO2 for addition to biotin and pyruvate
Why, in the absence of lactate, is oxaloacetate converted to malate in the
mitochondrion and then converted back to oxaloacetate in the
cytoplasm? Correct Answer-1) there is no transport protein for
oxaloacetate
2)Necessary in transport of NADH-->NAD+ out of mitochondria where
it can be re-reduced
Why, in the presence of lactate, is oxaloacetate not converted to malate
then reconverted to oxaloacetate? Why does is the lactate--> pyruvate
reaction for favorable> Correct Answer-Because oxidation of lactate to
oxaloacetate produces NADH in the cytoplasm, so there's no need to
shuttle it out of the mitochondria. saves energy
