Week 14: Gluconeogenesis Flashcards
What is gluconeogenesis?
Synthesis of glucose within the body from non-carbohydrate precursors
i.e ran out of glycogen
When does gluconeogenesis occur?
prolonged starvation, new glucose has to be synthesized
What are precursors for gluconeogenesis?
lactate
amino acids
glycerol
Where does the energy come from in gluconeogenesis?
oxidation of fatty acids released from adipose tissue
from the liver & kidneys
How many enzymes are needed in gluconeogenesis?
4 from liver
What is the intermediate compound in gluconeogenesis?
oxaloacetate in mitochondria
What is a anaplerotic reaction?
important for accepting acetyl groups from fat breakdown
Is gluconeogensis energy consuming?
YES only use when really need
What are the 4 enzymes used in gluconeogenesis?
glucose-6-phosphotase
fructose-1,6 bisphosphotase
Pyruvate carboxylate
PEP carboxylkinase
How much ATP is invested?
6ATP plus 2x NADH (5ATP)
for 1 molecule glucose
What is the process called that converts lactate to glucose?
Cori cycle
When is lactate formed?
formed in fast-twitch muscle under conditions of heavy exercise
What transports lactate to liver?
blood
What does the liver do to lactate?
Liver converts lactate back to glucose into bloodstream
What are amino acid precursors that can directly drive the formation of glucose called?
glycogenic amino acids
What are amino acids called that don’ directly drive formation of glucose?
ketogenic amino acids
form ketone bodies, breakdown of fat, relate to fat metabolism
What does level of glucose 6 phosphate mean?
high in fed state
low in starved state
What does presence of citrate, alanine & acetyl-CoA mean?
high when intermediates or building blocks are abundant
What does glucagon positively regulate?
fructose-1,6 bisphosphatase
What does glucagon negatively regulate?
FFK
What does insulin positively regulate?
FFK, breakdown glucose whilst we have plenty of it
What does insulin negatively regulate?
fructose-1,6 bis-phosphatase
What does fructose-1,6 biohosphatase enzyme convert?
converts fructose-1,6 bis-phosphate to fructose-6 phosphate (gluconeogenesis- pyruvate to glucose)
What does FFK enzyme convert?
converts fructose-6 phosphate to fructose-1,6 biphosphate (glycolysis- glucose to pyruvate)
