Lecture #69

  1. Gluconeogenisis
    • use metabolic preurosor fo new synthesis of glucose
    • reverse of glycolysisi
  2. why is glucose homeostatis  imp
    • for RBc because they have no mitochondria 
    • brain does not have gltcogen storage
    • biosynthesis of ribose for nucleic acids
    • glucose can be used to modify other proteins
    • important of homeosotatesof other molecules
  3. where does glucose product happen the most?
    • the liver 90%
    • kidney makes the rest but are selfish and only makes it for itself
  4. where does gluconeogenisis take place
    both cytosol and mtichon
  5. what are the precursors of gluconeogenisis
    • lactatepyruvate
    • glycerol
    • a-ketoacid
  6. what are the 4 enzymes that can reverse the 3 irreversible steps in the glycolysis
    • Pyruvate Carboxylase
    • PEPCK   phosphopenol pyruvate carboxykinase)
    • Fructise 1,6 bisphosphatase
    • G-6-P
  7. Which enzyme reverses step 10 in glycolysis for gluconeogensis ?
    • Pyruvate carboxylase
    • PEPCK ( in this order)
  8. Which enzyme reverses step 3 in glycolysis for gluconeogensis ?
    Fructose 16 bisphophatase
  9. Which enzyme reverses step 1 in glycolysis for gluconeogensis ?
  10. what are the similarities of gluconeogenisis and glycolsysis
    They share 7 reversible reactions
  11. Step1 gluconeogensis
    • change pyruvate to Oxaloacetate (OAA)  via pyruvate carboxylase 
    • this step isirreversible and allosterically activated ny acetyl coA
    • carboxyl group is added
  12. where foes steo 1 happen og vluconeo
  13. what does pyruvate carboxylase require to function
    biotin and ATP
  14. Step 2 of GNG
    • oAA changes to PEP vis PEPCK
    • irreversible
    • require GTP
    • carboxyl group is removed
  15. where does Step 2 of GNG take place
    1/2 in the mitochondria and 1/2/ cytosol
  16. Step 3 of GNG
    • f16bisphosphate changes to F-6-P  via F16bisphosphatase 
    • irreversible
  17. what inhibts step 3 of GNG
    F26BP and AMP
  18. what does the F26BP inhibit and activate
    • PFK1 is activated 
    • inhibti F1-6 bisphosphatatse
  19. step 4 of GNG
    • turn G6P to Glucose via glucose 6 phosphattase 
    • irreversible
  20. where does step 4 of GNG take place
    ER membrance
  21. what are the only organs that release glucoes?
    liver and kidney
  22. the enzyme G6Ptas only exists in which organs?
    liver and kidney
  23. how much ATp does GNG comsume ?
    6 ATP  and 2 NADh which leads to a total 12 ATP
  24. what are the precursors of GNG?
    • Lactate
    • Alanina
    • Glycerol
  25. how is lactate produces
    • from anerobic glycolysis 
    • primarily from RBC or excercising muscle cells
  26. how is alanine produced?
    • pyruvate transaimated in muscle
    • alanine exported from liver
    • alanine can transanimate back to pyruvate 
    • Glucose alanine cycle
  27. how to pyruvate created from lactate to enter the GNG
    lactate dehydrogenase
  28. what is the glucose alanine cycle?
    cycle btw the muscle and the liver where alanine is convereted to pyruvate pro
  29. what is a glucogenic amino acid
    aa that it can be utilized for GNG
  30. what is a ketogenic amino acid
    • aa that can only be utilized to make acetyl coa ad thus keton bodies 
  31. how is glycerol produced for GNG
    • when tricglycerides are hydrolyzes
    • fat cells
  32. how is Glycerol encorporated into GNG
    • used the enzymes glycroal kinas and glycerol 3 phosphate dehydrogenase to produce dihydroxyacetone phosphate (DHP) 
    • which is used ot create glucose in GNG
  33. when is GNG upregulated ?
    • Acetyl-coA
    • Fasting
    • prolong excercise
    • high protein, low carb
    • stress and injury 
    • plenty substrate available
    • Glucagon
    • activated (dephosphorylated ) FB-2
  34. when is GNG downregulated ? & why
    • alchol impariment
    • F26bisphosphate 
    • AMP
    • Insulin
    • well fed
    • eating
  35. where does energy for GNG come from during afsting ?
    Beta oxidation
  36. purpose of PPP
    • generate 5C sugar for nucleic acid synthesis 
    • NADH used for variety of pathways
  37. wwhat is the starting product for PP P
  38. the PPP can be broken down into
    oxidative and non oxidative
  39. oxidative PPP produces?
    NADPH and ribose 5 phosphate
  40. non-oxidative PPP produces?
    fructose 6 phosphate to fluel the glycolysis pathway
  41. what are the uses of NADPH ?
    • reduction of glutathione
    • reduction of 02 toform ROS
    • reductive biosynthesis 
    • create Ribose 5 phosphate 
    • to make nucleic acids
  42. what are the oxidative stesp of PP
    G6P >6phosphoglucono -δ-lactone> 6 phosphogluconate> ribose 5 phosphate
  43. what is the produce of  the oxidative of PP
    2X NaDPH
  44. in regards to reversibility is how do the nonaxidative and oxidative portions of PPP differ?
    non-oxidative is reversible while ox is not.
  45. hows does transketolase work and what does it need to function ?
    • move a ketone group around.
    • creates 3c and 5c  molecules within this transfer 

    it need TPP thiamine pyrophosphate to funtion.
  46. hows does transaldolase work and what does it need to function ?
    transfer 3 carbon unit
  47. what cause hemolytic anemia and G5PD deficiency ?
    • RBc generate alot oft ROs reactive oxygen species and this this can damge HB
    • usually the NADPH in the PPP reduce GSH ( glutathione and reduce the ROS  thus repairing and preventing BY damage. When the PPP is down this causes an increase in the ROS and the RBC start to get lysed by the ROS 
    • Heinz bodies form in RBC and RBC membrance becomes very fragile
  48. whatis glutathione
    an antioxidant produces by the PPP
  49. what is significant about glucose 6 phosphate dehydrogenase ?
    It is the first enzyme in both PPP and glycolysis
  50. what population does the G6PD deficieny affect?
    10% African american man

    • there is a G6PD mutation that correlated around the malarial belt 
    • people with sickle cell anemia
    • Thalassemia
Card Set
Lecture #69
Gluconeogenesis and Pentose Phosphate Pathway