1.11-GlucoNeoGenesis Flashcards
Do you find GlucoNeoGenesis in other organisms?
YES! A universal pathway…Anlimals, Plants, Fungi, and Microorganisms!
What are the four starting materials/precursors for Glucose?
- Lactate 2.Pyruvate 3. Glycerol 4. Amino Acids (18 out of 20)
When is GNG most active?
Inbetween meals, so during sleep and builds before breakfast, lunch, dinner
What are some of the main tissues that mainly depend on GNG? Think low blood supply again!
Brain, RBCs, Kidney, Testes
What is the cycle that Muscles break down glucose to lactate and Liver builds lactate to Glucose?
The Cori Cycle
What does the Cori Cycle do for blood pH?
It helps keep pH normal by getting Lactate (acidic) out of the blood
What two organs perform GNG? Which one does the Lion’s Share?
Liver & Kidney. Liver does the lions share
Is GNG simply a reversal of Glycolysis? What atet the 3 bypasses?
Nope, there are 3 irreversible steps that we will have to bypass! 1. Pyruvate–>PEP (Pyruvate Carboxylase) 2. Fructose-1,6-BisPhosphatase 3. Glucose-6-Phospatase
Are the Bypasses reversible?
No, they only go to GNG!
Where does each of the four starting materials enter GNG?
1.Lactate-Enters by being converted to Pyruvate before the first step 2. Amino Acids-a.some are converted to pyruvate b. some are converted to Oxaloacitate for step 2 3. Pyruvate-first step of GNG 4. Glycerol-enters late, in part 2 go GNG
What is the first step in the MAJOR pathway for Pyuvate to PEP? What Enzyme is used? Where does it happen? Is there ATP used?
1st step: Pyruvate–>Oxaloacetate Enzyme: Pyruvate Carboxylase. Occurs in the mitochondrial matrix. 1 ATP used
What is PC? What is it controlled by? What “type” of reaction does it catalyze?
Pyruvate Carboxylase. Controlled by HIGH Acetyl-CoA. ANA-PLE-ROTIC reaction
What is the Second step in the MAJOR pathway for pyruvate to PEP? What enzyme? Where?
2nd step: Oxaloacetate–>Malate. Enzyme: NADH Malate Dehydrogenase. Occurs in mitochondria (but now malate can exit!)
What is the third step in the MAJOR pathway (pyruvate to PEP? What enzyme? Where?
3rd Step: Malate –> Oxaloacetate Enzyme: NAD+ Malate Dehydrogenase. In cytosol
What is the simultaneous final step (so 3rd/4th step) of Pyruvate to PEP? What KEY enzyme is used? What form of energy is used?
3rd/4th step: Oxaloacetate–>PEP (Phospho-Enol-Pyruvate). KEY enzyme: PEP Carboxy-Kinase. Energy: 1 GTP
Why is the bypass shorter if lactate is the starting material?
It is more energetically favorable! (low NADH/NAD+ Ratio)
What is Bypass #2? When is it in the grand scheme of things?
Fructose-1,6-Bisphosphate–>Fructose-6-Phospahte USING: Fructose-1,6-BisPhosphatase…3rd to LAST step of GNG
What is Bypass #3? When is it in the grand scheme of things?
Glucose-6-Phosphate—> Glucose USING: Glucose-6-Phosphatase…LAST step of GNG
What is the distribution of AAs that enter GNG via Pyruvate vs entering via CAC?
6 enter via pyruvate, the remaining 12 enter via CAC
What are the two easy steps to introduce Glycerol into GNG?
- Glycerol–>Glycerol-3-Phosphate 2. Glycerol-3-Phosphate–>DHAP
In terms of ATP: which is harder to do: GNG or Glycolysis?
GNG 6ATP investment (2NADH) vs Glycolysis: 2ATP investment
How does Pyruvate Decarboxylation regulate GNG?
Lots of Acetyl CoA inhibits Pyruvate DeHydrogenase AND Stimulates Pyruvate Carboxylase
What are the two regulators of GNG?
Pyruvate Carboxylase & PFK1/Fructose-1,6-BisPhospatase
What is the GENERAL theme of PFK1/Fructose-1,6-BisPhosphatase regulation? What happens with presence of Low energy molecules? High energy molecules?
LOW energy molecules=Glycolysis! High energy mols present=GNG!
