Gluconeogenesis Flashcards
In the absence of insulin, most of the body utilises FA for energy, but what does the brain and red blood cells use?
glucose
What happens to glucose levels between meals?
They drop
Whats the solution to decreasing glucose levels
- Synthesises new glucose molecules and release into the blood
- Best solution: convert FA into glucose
- X don’t have the enzymes, although glycerol can be converted
- Simplest way would be to reverse glycolysis
What are the irreversible steps to glycolysis ?
Whats the energy balance?
Irreversible reaction 1 :(PEP –> pyruvate)- can’t do this in 1 step so need an alternative pathway
- Alternative pathway that consumes ATP
- Two-step process: 2 enzymes
What happens in each of the stages?
What happens in the Irreversible reaction 2: (Fructose-1,6-biphosphate –> F6P)
What happens in the Irreversible reaction 3: (G6P –> glucose); occurs in ER
Whats the problem with gluconeogenesis?
Whats a solution?
- no stores of pyruvate to maintain gluconeogenesis
- Solution to this problem:
- Lactate via Cori cycle
- Glucogenic amino acids
What happens in the cori cycle?
What does it occur between?
A cycle between the liver and whatever tissue is producing lactate
The following shows glucogenic AA
- Alanine is quantitively most important
- Muscle catabolism releases ala into blood
- Converted to pyruvate
The following shows the cori and alanine cycle
When glycerol is converted to what ever is needed in the body, what is used?
- 1 ATP consumed
- 1 NADH created= 3 x ATP
- 2x ATP overall
What are the steps to how Galactose produces G6P?
What are the steps to how Fructose and Mannose produce F6P?
Identify the structure of Glucose, Galactose and Mannose
The following shows how glucose is used over the day
Define Glycolysis
Glycolysis is the process of breaking down glucose. Glycolysis can take place with or without oxygen
Define gluconeogenesis
Gluconeogenesis (GNG) is a metabolic pathway that results in the generation of glucose from certain non-carbohydrate carbon substrates
Define Glucogenesis?
The formation of glucose within the animal body from any product of glycolysis
Define Glycogenolysis
Glycogenolysis is the breakdown of glycogen (n) to glucose-1-phosphate and glycogen (n-1)
Define Glycogenesis
The formation of glycogen from sugar
