Gluconeogenesis Flashcards
What is the starting input for gluconeogenesis and what is the final output?
Pyruvate from a non-carbohydrate source is the input required for the
gluconeogenesis to begin, whereas the output is glucose.
Where does the input required for gluconeogenesis come from?
Pyruvate from a non-carbohydrate source needed to begin gluconeogenesis comes from amino acid metabolism of alanine and aspartate, the conversion of
oxaloacetate to pyruvate and the conversion of lactate into pyruvate (in the liver).
What is the final output of gluconeogenesis used for?
For what purpose?
The glucose produced in gluconeogenesis is then moved from the cell into the
blood.
Once in the blood the glucose can be trafficked to where it is required. The glucose can be taken to glucose dependent organs such as the brain
and the kidney.
Once glucose reaches these organs, glycolysis and the common metabolic pathway are used to generate a lot of ATP from the glucose.
Why is it necessary for us to perform the gluconeogenesis?
Why is it important?
Gluconeogenesis is required in times where carbohydrate intake is restricted. The
body needs to maintain the blood glucose between 4-7.8 mmol/L.
Having a constant
supply of glucose in the blood allows it to be taken to cells and organs that required
glucose to derive ATP.
Gluconeogenesis is under the control of enzymatic regulation at several steps throughout the reaction.
Why is enzymatic regulation of the gluconeogenesis required?
Enzymatic control of gluconeogenesis allows gluconeogenesis to be performed when more glucose is required to either increase the blood glucose or generate ATP or both.
In contrast, when glucose is abundant after an individual has ingested a carbohydrate rich meal, no more glucose needs to be made so enzymes regulation is
used to stop gluconeogenesis.
Why do some of the reactions of gluconeogenesis use the exact same enzymes as
those used in glycolysis?
Gluconeogenesis and glycolysis are essentially metabolic reactions that are the reverse of one another. Gluconeogenesis uses a non-carbohydrate source of
pyruvate as the input to produce glucose (output), whereas glycolysis uses glucose to produce pyruvate.
Which steps of glycolysis can not be reversed by using the identical enzymes in
gluconeogenesis?
Three of the glycolysis reactions can not be reversed in gluconeogenesis using the
same enzymes.
The irreversible reactions of glycolysis are step 1, 3 and 10.
How does gluconeogenesis bypass the non-reversible steps of glycolysis?
Gluconeogenesis uses different enzymes to bypass the irreversible reactions of
glycolysis.
