Bio 8 - Gluconeogenesis Flashcards
What enzymes are involved in turning pyruvate back up to phosphoenolypyruvate?
Pyruvate carboxylase + biotin): converts pyruvate to oxaloacetate. PEP carboxykinase: converts oxaloacetate to Phosphoenolpyruvate.
Where does gluconeogenesis take place? When does it take place?
Hepatocytes, kidney, and intestinal epithelium. Starts to take place when blood glucose is low. Hepatocytes starts doing 2 things: It shares its glycogen stores and starts converting other molecules (Odd chains FAs generating propionyl CoA, TCA cycle molecules, AA) into pyruvate, and using that pyruvate to make glucose.
What is the formula for Gibbs free energy?
Delta G = Delta H - T Delta S.
G: Gibbs free energy. H: energy/enthalpy (heat change in constant pressure rxns). S: entropy. T: temperature.
What is the rate-limiting enzyme of De novo pyrimidine synthesis?
Carbomyl phosphate synthase 2.
What is the rate-limiting enzyme of de novo purine synthesis?
Glutamine PRPP amidotransferase.
What is the rate-limiting enzyme of glycolysis?
Phosphofructokinase-1.
What is the rate-limiting enzyme of gluconeogenesis?
Fructose-1,6-bisphosphatase.
What is the rate-limiting enzyme of glycogen synthesis?
Glycogen synthase.
What is the rate-limiting enzyme of glycogenolysis?
Glycogen phosphorylase.
What is the rate-limiting enzyme of TCA cycle?
Isocitrate dehydrogenase.
What is the rate-limiting enzyme of hexose monophosphate shunt?
Glucose-6-phophate dehydrogenase.
What irreversible enzymes are involved in gluconeogenesis?
Pyruvate carboxylase + biotin. PEP carboxykinase. Fructose-1,6-bisphosphatase. Glucose-6-phosphatase.
What enzyme catalyzes the rate-limiting step in gluconeogenesis?
Fructose-1,6-bisphosphatase.
Order the following molecules by how much energy they contain that can be available to fuel endergonic reactions: pyruvate, adenosine monophosphate, glucose, adenosine, adenosine triphosphate.
Highest to lowest: glucose, pyruvate, ATP, AMP, adenosine.
What is the rate-limiting enzyme of gluconeogenesis? What are the substrates that inhibit this enzyme and which one stimulate it?
Fructose-1,6-bisphosphatase. Stimulated by ATP. Inhibited by AMP, fructose-2,6-bisphosphate.
