Carbs 4 Flashcards
Where does Gluconeogenesis occur ?
In the hepatocytes in the Liver
How many irreversible and reversible reactions are there in Glycolysis ?
Irreversible: 3
Reversible: 7
Where in the cell does Gluconeogenesis take place ?
In the cytosol & the mitochondria
How many bypass reactions are there in Gluconeogenesis ?
4 Bypass reactions
What does Pyruvate turn into within the mitochondria in the first bypass reaction of Gluconeogenesis ?
Pyruvate -> Oxaloacetate -> Malate
What are the enzymes that catalyze these reactions ?
Pyruvate -> Oxaloacetate = Pyruvate Carboxylase
Oxaloacetate -> Malate = Malate Dehydrogenase
Once Malate has left the mitochondria what does Malate turn into ?
Malate -> Oxaloacetate -> PEP
What enzymes catalyze these reactions ?
Malate -> Oxaloacetate = Malate Dehydrogenase
Oxaloacetate -> PEP = PEP Carboxylase
When Lactate is the substrate what occurs ?
Lactate -> Pyruvate via Lactate Dehydrogenase
What happens within the mitochondria when lactate is the substrate ?
Pyruvate -> Oxaloacetate ->PEP
What enzymes catalyze these reactions ?
Pyruvate -> Oxaloacetate = Pyruvate Carboxylase
Oxaloacetate -> PEP = PEP Carboxylase
What happens outside the mitochondria when lactate is the substrate ?
PEP leaves the mitochondria & this is the final step
What is the 3rd bypass reaction in Gluconeogenesis ?
Fructose-1,6-Bisphosphate -> F-6-P
What is the catalyst in the 3rd bypass reaction ?
F-1,6-P is the catalyst in this reaction
What is the 4th bypass reaction in Gluconeogenesis ?
G-6-P -> Glucose
What is the catalyst in the 4th bypass reaction ?
G-6-P
How does the body metabolize Fructose & Galactose ?
The body does not have a specific pathway for these carbohydrates, they can enter glycolysis at any point.
How is Fructose broken down ?
Fructose -> F-1-P -> Glyceraldehyde + Dihydroxyacetone phosphate -> Glyceraldehyde -3- P
What enzymes catalyze the breakdown of Fructose into Glyceraldehyde-3-P ?
Fructose -> F-1-P = Fructokinase
F-1-P -> Glyceraldehyde = F-1-P Adolase
Glyceraldehyde -> Glyceraldehyde-3-P = Triose Kinase
How is Galactose broken down ?
Galactose -> G-1-P
What catalyses the breakdown of Galactose ?
UDP (Sugar nucleotide derivative)
What is the purpose of the pentose phosphate pathway ?
Production of NADPH for all organisms & produces pentoses for synthesis of RNA & DNA
What is the starting substrate of the Pentose Phosphate pathway ?
G-6-P
What are the two phases in the pentose phosphate pathway & which is reversible & irreversible ?
Oxidative (irreversible) & Non-oxidative (reversible)
What does the Oxidative phase of the Pentose Phosphate pathway consist of ?
G-6-P -> 6-Phosphogluconate -> Ribulose -5-Phosphate ->Ribose-5-Phosphate -> Nucleotides,RNA,DNA & Co-enzymes
What does the on-oxidative phase of the Pentose Phosphate pathway consist of ?
G-6-P -> 6-Phosphogluconate -> Ribulose -5-Phosphate
