Exam 3: Gluconeogenesis Flashcards
What are the major precursors for Gluconeogenesis?
- Lactate
- Amino Acids
- Glycerol
What is gluconeogenesis?
- The synthesis of glucose from noncarbohydate precursors.
- A pathway that converts pyruvate into glucose.
What are the three reactions in glycolysis that are “irreversible”?
- Hexokinase Step
- Phosphofructokinase Step
- Pyruvate Kinase Step
What are the four enzymes that are used to “by-pass” the irreversible steps of glycolysis
- Pyruvate Carboxylase
- Phosphoenolpyruvate Carboxykinase
- Fructose 1,6-bisphosphatase
- Glucose 6-phosphatase
Approx how many ATP are required to conver two pyruvate to Glucose?
6
Where is Pyruvate Carboxylase found?
In the mitochondria.
How is Mitochondrial oxaloacetate shuttled to the cytoplasm?
Via a malate shuttle
Explain how the Malate Shuttle works to move oxaloacetate (OAA) to the cytosol from the mitochondira.
OAA is reduced to malate by mitochondrial malate dehydrogenase. Then malate can be transported to the cytosol where it is reoxidized to OAA by cytosolic malate dehydrogenase as NAD+ is reduced to NADH.
Where is glucose 6-phosphatase located in the cell?
In the liver, it is in the Endoplasmic reticulum lumen
How does glucose 6-phosphate get in the ER?
A specific protein (T1) transports it in and another protein (T3) transports the glucose back to the cytoplasm.
What determins if gluconeogenesis or glycolysis will be active?
ATP/ADP ratio
T/F, Glycolysis generates ATP, Gluconeogenesis consumes ATP.
True
With a high level of ATP which process is more favorable to run?
Gluconeogenesis
In the liver _________ strongly stimulates phosphofructosekinase and inhibits fructose 1,6-bisphosphatase.
Fructose 2,6-bisphosphate
What two enzymes regulate the concentration of fructose 2,6-bisphosphate?
- Phosphofructokinase 2 (PFK2)
- Fructose Bisphosphatase 2 (FBPase2)
