Glucogenesis Flashcards
What is gluconeogenesis?
The production of glucose from non-carbohydrate sources
It involves precursors like glycerol, glucogenic amino acids, and lactate.
When does gluconeogenesis take place?
Occurs due to starvation for 12 hours or prolonged exercise
Where does gluconeogenesis primarily occur in the body?
In the liver, kidney cortex, and intestines
What are the key differences between gluconeogenesis and glycolysis?
- Gluconeogenesis is not a simple reversal of glycolysis
- Bypasses three irreversible reactions of glycolysis
What is the main precursor for gluconeogenesis derived from lactate?
Pyruvate
What is the Cori Cycle?
Lactate from anaerobic glycolysis in muscle is transported back to the liver and converted to pyruvate
Which amino acids are considered important glucogenic amino acids?
- Alanine
- Glutamine
What is a key intermediate in gluconeogenesis?
Pyruvate
How is pyruvate converted to oxaloacetate during gluconeogenesis?
In the mitochondrion using the enzyme pyruvate carboxylase
What is the energy requirement for the conversion of pyruvate to phosphoenolpyruvate?
Requires energy input from ATP and GTP
What is the ΔG value for the conversion of phosphoenolpyruvate to pyruvate?
-54.8 kJ/mol
True or False: Gluconeogenesis is energetically cheaper than glycolysis.
False
What enzyme catalyzes the hydrolysis of fructose 1,6 bisphosphate in gluconeogenesis?
Fructose 1,6 bisphosphatase
Fill in the blank: Glycogenesis is the formation of _______ from glucose.
glycogen
What regulates the conversion of glucose into glycogen?
The presence of insulin and the demand for ATP and glucose
What is the overall ΔG’ for gluconeogenesis?
-9 kJ/mol
What happens to blood glucose levels during prolonged exercise?
They need to be maintained through gluconeogenesis
What is the significance of gluconeogenesis outside of animals?
It is also used in plants and microorganisms
What metabolic fate does pyruvate have in adipose tissue?
Converted to fat, not glucose
What is the main purpose of gluconeogenesis?
To maintain stable blood sugar levels
