WK1_1 Gluconeogenesis Flashcards
A patient presented with a bacterial infection that produced an endotoxin that inhibits phosphoenolpyruvate carboxykinase. In this patient, then under theses conditions, glucose production from which of the following precursors would be inhibited?
alanine
a common intermediate in the conversion of glycerol and lactate to glucose is which of the following?
glucose-6-phosphate
gluconeogenesis
synthesis of glucose from non-sugar precursors, including lactate, glycerol and glycogenic aa’s
where does gluconeogeneis take place?
in the liver (primary site) & kidneys (lesser extent)
gluconeogenesis helps maintain the homeostasis of _____ during _____ and _____ which in turn provides a constant supply of glucose for oxidation by RBCs and the brain.
blood glucose levels; fasting; starvation
during fasting, blood glucose is generated by _____ in the liver, and to a lesser extent by _____.
glycogenolysis; gluconeogenesis
during starvation, liver glycogen stores are depleted and _____ is the only pathway for glucose production
gluconeogenesis
T/F gluconeogenesis is a reversal of glycolysis
FALSE. gluconeogenesis is NOT a reversal of glycolysis
do gluconeogenesis and glycolysis have independent or dependent regulation?
independent
T/F gluconeogenesis and glycolysis are competing pathways.
TRUE
why are gluconeogenesis and glycolysis competing pathways?
since the product of gluconeogenesis (glucose) is the substrate for glycolysis
gluconeogenesis is stimulated by _____ and inhibited by _____
glucagon; insulin
in the liver, gluconeogenesis and glycolysis are _____ regulated by insulin and glucagon in order to prevent futile cycling of glucose.
reciprocally
reciprocal regulation of gluconeogenesis and glycolysis:
1) ?
2) ?
1) prevents the oxidation of glucose generated by gluconeogenesis
2) allows the newly synthesized glucose to be deposited into the circulation
insulin and glucagon reciprocally regulate glycogenesis and glycogenolysis in the liver, which prevents:
futile cycling of the glucose produced by glycogenolysis by preventing its incorporation into glycogen
when does gluconeogenesis occur?
during the fasting state and starvation
where (organelle) does gluconeogenesis start?
mitochondria
where does gluconeogenesis go from mitochondria?
cytoplasm
where can you find glycerol kinase?
only in the liver
what are the 3 ways that glycogenic amino acids enter gluconeogenesis?
1) by conversion to pyruvate which then enters gluconeogenesis
OR
2) conversion to intermediates fo the TCA cycle which are then converted to oxaloacetate which enters gluconeogenesis
OR
3) by conversion to oxaloacetate which enters gluconeogenesis
how much % of the glucose produced by gluconeogenesis is derived by glycogenic amino acids produced by the degradation of muscle proteins?
60%
how much % of the glucose produced by gluconeogenesis is derived by lactate via the Cori cycle?
28%
how much % of the glucose produced by gluconeogenesis is derived by glycerol produced by lipolysis in adipose tissue?
12%
