Fermentation, Gluconeogenesis, Pentose Phosphate pathway, Glycogen synthesis Flashcards
What does fermentation in yeasts consist in ?
Two step reduction of pyruvate to alcohol with production of CO2
What does fermentation in humans consist in ?
Reversible lactic acid fermentation because lactate can then be transported into the liver to make glucose
Where does gluconeogenesis usually happen?
In the liver
Is gluconegoenesis thermodynamically stable ?
Yes just like. glycolysis
Steps of gluconeogenesis
Pyruvate»_space; oxaloacetate (pyruvate carboxylase)
oxaloacetate»_space; PEP ( PEP carboxykinase)
PEP can be then transformed into glucose by reverse glycolysis with same enzymes except for the two irreversible step
What are the two enzymes used in gluconeogenesis to bypass the 2 irreversible steps?
- Fructose-1-g-bisphophatase ( from Fruc.1-6-Bisph.»_space; F6P)
2. Glucose-6-Phosphatase ( G6P» GLUCOSE)
Can animals produce glucose from fatty acids?
NO, because product of fatty acid oxidation is Acetyl co A and it cannot be converted to oxaloacetate.
What does gluconeogenesis require?
2 pyruvate
6 atp
2 nadh
Where does pyruvate carboxylase act?
In mitochondria and converts Pyruvate to oxaloacetate.
What is the entry point of Pentose phosphate pathway?
Glucose-6-phosphate
What are the products of Pentose Phosphate Pathway?
NADPH (anabolism)
Ribose-5-phosphate (nucleotides)
What starts a new glycogen chain?
Glycogenin (7 UDP gluc)
Where is UDP originated from?
From glucose-1-phosphate which come from G6P (phosphogluco-mutase)
What is the product of glycogen phosphorylase?
Glucose-1-Phosphate
How does glycogen phosphorylase cleave glucose from glycogen?
It works on non reducing ends and stops only when it reaches 4 glucoses from alpha1-6 branching point. At this pain the debranching enzyme transfers 3 glucose to non reducing end where glyc. phosph. can start working again whereas the one glucose is released
