module 3- gluconeogenesis Flashcards
primary function of gluconeogenesis in animals
maintaining adequate glucose levels in the blood
primary function of gluconeogenesis in plants
use glucose to synthesize starch, cellulose & sucrose
where does gluconeogenesis occur?
liver (mostly) and kidney
gluconeogenesis pathway
pyruvate into glucose
3 precursors of gluconeogenesis
lactate, amino acids & glycerol
lactate is converted back to pyruvate by ( ) and enters gluconeogenesis pathway
lactate dehydrogenase
amino acids are metabolized into ( )
intermediates
glycerol is derived from ( ) and converted into ( )
triacylglycerols, DHAP
what enzymes drives pyruvate -> oxaloacetate
pyruvate carboxylase
T or F: acetyl CoA is an obligate allosteric activator
T
where does pyruvate -> oxaloacetate reaction begin?
mitochondria
what enzyme drives fructose 1,6-BP -> fructose 6-P?
fructose 1,6-bisphosphatase
how is fructose 1,6-bisphosphatase regulated?
allosterically
what enzyme drives fructose 6-P -> glucose 6-P?
phosphoglucose isomerase
inputs & outputs of gluconeogenesis
inputs- 2 pyruvate, 4 ATP, 2 GTP, 2 NADH, 2 H, 6 H2O
outputs- 1 glucose, 4 ADP, 2 GDP, 6Pi, 2 NAD
glucose & gluconeogenesis are ( ) regulated
reciprocally
what pathway is favoured when glucose is abundant?
glycolysis
what pathway is favoured when glucose is scare?
gluconeogenesis
what is the major regulatory reaction of gluconeogenesis & what enzyme?
fructose 6-P -> fructose 1,6-BP
enzyme: fructose 1,6 bisphosphatase
what is the major regulatory reaction of glycolysis & what enzyme?
fructose 6-P -> fructose 1,6-BP
enzyme: PFK
AMP (inhibits/activates) PFK & stimulates (glycolysis/gluconeogenesis) = fructose 1,6 BP is ( ) and gluconeogenesis is ( )
activates, glycolysis
inhibited, slowed
citrate (activates/inhibits) PFK & stimulates (enzyme?) = activation of (gluconeogenesis/glycolysis)
inhibits, PFK, gluconeogenesis
pyruvate & PEP interconversion are ( ) regulated
reciprocally
increased ADP = ( ) conversion of pyruvate -> PEP = favours (glycolysis/gluconeogenesis) & (ADP/ATP) production
inhibits, glycolysis, ATP
allosteric regulator effect is highly dependent on its ( )
concentration
T or F: lactate produced by muscles is converted to glucose in the liver via the cori cycle
T
fructose 2,6-BP (activates/inhibits ) PFK = (glycolysis/gluconeogenesis) activation = (inhibits/activates) fructose 1,6 BP = (activates/deactivates) gluconeogenesis
activates, glycolysis, inhibits, deactivates
low glucagon = ( ) insulin = favours which pathway
increased, glycolysis
what pathway is present during starvation
gluconeogenesis
what pathway is present in the fed state
glycolysis
insulin resistance
excess glucose levels
What is the terminal enzyme?
Glucose 6-P
increased ATP = what pathway
increased AMP = what pathway
gluconeogenesis, glycolysis
increased fructose 2,6 BP = what pathway
glycolysis
increased citrate = what pathway
gluconeogenesis
increased acetyl CoA = what pathway
gluconeogenesis
increased insulin = what pathway
glycolysis
increased glucagon = what pathway
gluconeogenesis
Main 3 enzymes in gluconeogenesis
pyruvate decarboxylase, fructose 1,6-bisphosphatase, glucose 6-phosphatase
