Flashcards in 1.11 Gluconeogenesis Deck (40):
Four main precursors for Gluconeogenesis
Most amino acids
When does gluconeogenesis occur?
When our blood glucose is depleted
Which three steps of Glycolysis are not reversable steps in GNG?
Glucose to G-6-P
F-6-P to F-1,6-P
PEP to Pyruvate
Lactate is made to Glucose during the Cori Cycle in what body structure?
Cori Cycle involves what two body structures
In GNG, What enzyme converts Pyruvate to Oxaloacetate
What is the pathway from Pyruvate to PEP in GNG
Pyruvate --> Oxaloacetate --> PEP
What enzyme is used to convert Oxaloacetate to PEP
What substrates are needed to convert Pyruvate to Oxaloacetate other than the enzyme?
ATP and HCO3 (carboxyl group to add a carbon)
What other substrates are involved in converting oxaloacetate to PEP other than its enzyme
What part of GNG occurs in the mitochondria
Pyruvate to Oxaloacetate
How does Oxaloacetate leave the mitochondria?
It is converted to Malate and transported across the mitochondrial membrane. In the cytosol it is converted back to Oxaloacetate.
What is used directly in the malate dehydrogenase enzyme
NAD and NADH
High levels of what stimulate the reaction of Pyruvate to Oxaloacetate
How is Acetyl CoA concentration regulatory?
Depending on Acetyl CoA concentration, Pyruvate will either proceed to Acetyl CoA or reverse to Oxaloacetate and PEP by GNG
What is the net products of Glunoneogenesis
What coenzyme is attached to Pyruvate Carboxylase during Gluconeogenesis
Why is the transport of Oxaloacetate by Malate Dehydrogenase considered a Circuitous?
The production of NAD+ for Mitochondria
The production of NADH for Cytosol
Where is the major site of GNG
Liver but also takes place somewhat in the kidney
Is NADH produced in the mitochondrial matrix or in the cytosol during the malate dehydrogenase
Cytosol, NAD+ --> NADH
At what point does CO2 leave during the conversion of Pyruvate to PEP
CO2 leaves during the conversion of Oxaloacetate to PEP by PEP Carboxykinase
The conversion of Lactate to Pyruvate yields what?
What enzyme catalyzes Lactate to Pyruvate
What enzyme catalyzes the GNG reaction of F 1,6-P to F 6-P
F 6-P is formed by hydrolysis of the phosphate group at what Carbon
What enzyme catalyzes Glucose 6-Phosphatase to Glucose
Glucose 6 phosphatase
Where is G-6-Phosphatase NOT PRESENT?
In the Brain and muscle it is not present so glucose cannot be formed by these organs
Where is Glucose 6-Phosphatase located?
In the membrane of ER
Where does Glycerol enter the Gluconeogenesis cycle to be used as a precursor to Glucose
At the point of the two 3 carbon intermediates of Glycolysis
How many high energy phosphate bonds are used during Gluconeogenesis
6 (4x ATP, 2x GTP)
Pyruvate Carboxylase is stimulated by what?
Describe the process when the energy needs of the cell have been met?
NADH accumulates which inhibits the citric acid cycle and levels of Acetyl CoA go up
Do levels of Acetyl CoA regulate Pyruvate Dehydrogenase
Yes, High levels of Acetyl CoA inhibit Pyruvate dehydrogenase and activate Pyruvate Carboxylase
When does the reaction move towards Fructose 1,6-phosphatase
When Low Energy charge are present
High concentration of Fructose 2,6 bisphosphate
Elevated levels of AMP and depressed levels of citrate and ATP do what?
Move reaction towards Fructose 1,6-phosphate
High energy charge and low concentration of Fructose 2,6 bisphosphate do what?
Move the reaction towards Fructose 6 phosphate
In response to starvation the pancreas releases what?
When glucagon is released, the level of Fructose 2,6 bisphosphate does what?
The decreased levels of Fructose 2,6 bisphosphate causes what?
decreased activity of PFK1 and increases activity of Fructose 1,6-phosphatase