Biosynthesis of Glucose Flashcards
Gluconeogenesis
Glucose being synthesized by the body by non-carbohydrate sources.
When does the body make glucose?
When there is not a steady supply of glucose in the blood.
Ex: after fasting, levels decline. Glucose needs to be maintained at 70-100 mg/dL at all times.
Gluconeogensis occurs mainly where
Liver. Lesser extent in the kidneys and small intestine.
Non carbohydrate sources used in gluconeogenesis
Lactacte (produced during fermentation, and transported to the liver to be converted to pyruvate) - converted to pyruvate.
Glycogenic amino acids- converted to pyruvate or intermediaries of krebs cycle (which are eventually be converted to oxaloacetate)
Pyruvate
Pathway of gluconeogenesis. Exceptions of how it differs from the reversal of glycolysis?
Begins with pyruvate or oxaloacetate and is the reverse of glycolysis with 3 exceptions.
Since we dont have energy to expend, we must use different enzymes during step 10, 3, and 1 of glycolysis.
Step 10- 2 different enzymes, and an intermediary (oxaloacetate)
Step 3- 1 enzyme
Step 1- 1 enzyme
Gluconeogenesis is the reversal of ___
Glycolysis.
Begins with pyruvate or oxaloacetate and ends with glucose.
How do you drive exergonic reactions in reverse in gluconeogenesis? what does this mean?
3 exergonic reactions occurs during glycolysis, meaning the release of energy.
To do these steps in reverse, we would need to input a lot of energy. But we dont have energy.. we didn’t eat. So what do you do?
The last step of glycolysis (step 10) is an exergonic reaction, releases energy.
This step is the first step in gluconeogenesis. How does this process differ?
2 different enzymes are used and the intermediate, oxaloacetate is used.
Why do you need oxaloacetate for gluconeogensis to occur?
Oxaloacetate is needed as an intermediary to power moving backwards through step 10 in glycolysis, an exergonic reaction.
