Gluconeogenesis Flashcards
muscle gluconeogenesis
used ONLY to replenish muscle glycogen for contraction when needed
gluconeogenesis is most active in _
hepatocytes
gluconeogenesis uses _ as starting substrates
glycolysis and TCA intermediates from degradation of glucose and other sugars, amino acids, and fats
Cori cycle
lactate is transported to liver and made into glucose through gluconeogenesis and then exported back to peripheral tissues
Glc-Ala cycle
muscle shunts pyruvate (in the form of alanine) into the liver for gluconeogenesis and then the liver will transport the glucose back to the muscle
triacylglycerol degradation
degradation of TAGs produces glycerol which can enter gluconeogenesis after conversion to DHAP in the liver (glycerol kinase in the liver for conversion)
Why can’t even chain fatty acids be used to make glucose?
because when even chain fatty acids are degraded, they will form acetyl-CoA, which can not go through a reverse reaction to form pyruvate
odd chain fatty acids
degradation will form propionyl-CoA, which can be converted to succinyl-CoA for gluconeogenesis (succinyl-CoA can form oxaloacetate, a substrate in the process)
Which amino acids can not be used as substrates for gluconeogenesis?
leucine and lysine because they produce acetyl-CoA
irreversible gluconeogenesis steps
- pyruvate –> PEP
- fructose-1,6-bisphosphate –> fructose-6-phosphate
- glucose-6-phosphate –> glucose
pyruvate –> PEP
pyruvate –> oxalaoacetate (by pyruvate carboxylase) –> PEP (by PEP carboxy kinase)
pyruvate carboxylase requires _
ATP –> ADP
PEPCK requires _
GTP –> GDP
What is added to pyruvate to make OAA?
a CO2 from biotin
What happens to OAA to make PEP?
decarboxylation (removing previous CO2) and phosphorylation
