Glycolysis Flashcards
What is glycolysis?
- It is the splitting of sugar
- It is the breakdown of glucose to produce energy in the form of ATP & NADH
- This metabolic pathway occurs in the cytosol of the cell
- It converts glucose –> pyruvate, which feeds into the TCA/Krebs Cycle
- It involves 2 phases: Energy Investment Phase and the Energy Generation Phase
It is an aerobic or anaerobic pathway?
It generates ATP anaerobically and provides fuel for aerobic generating pathways
What is glucose coverted to via glycolysis?
1 molecule of Glucose (6C compound) is converted to 2 molecules of Pyruvate (3C compound)
Energy Investment Phase: RXN 1
Conversion of glucose –> glucose-6-phosphate
Phosphorylation RXN
Hexokinase
Mg2+ required
1 molecule of phosphate is transferred from ATP to glucose
ATP converted to ADP+H+
Irreversible RXN
Energy Investment Phase: RXN 2
Conversion of glucose-6-phosphate –> fructose-6-phosphate
Isomerization RXN
Phosphoglucoisomerase
Reversible RXN
Energy Investment Phase: RXN 3
Conversion of fructose-6-phosphate –> fructose-1,6-bisphosphate
Phosphorylation RXN
Phosphofructokinase (PFK) : Allosteric Enzyme
Mg2+ required
Phosphate is added to the first C of the fructose ring
ATP is converted to ADP+H+
Irreversible RXN
Energy Investment Phase: RXN 4
Cleavage of fructose-1,6-bisphosphate into 2 triose sugars
- Glyceraldehyde-3-Phosphate
- Dihydroxyacetone Phosphate
Aldolase
Reversible RXN
Energy Investment Phase: RXN 5
Conversion of Dihydroxyacetone –> Glyceraldehyde-3-Phosphate
Isomerization RXN
Isomerase
Reversible
Energy Generation Phase: RXN 6
Conversion of Glyceraldehyde-3-Phosphate –> 1,3-Bisphosphoglycerate
Phosphorylation & Oxidation
Dehydrogenase
Production of NADH
Reversible RXN
Energy Investment Phase: RXN 7
Conversion of 1-3-Bisphosphoglycerate –> 3-Phosphoglycerate
Substrate level phosphorylation
Phosphoglycerate Kinase
ADP converted to ATP
Mg2+ required
Reversible RXN
Energy Generation Phase: RXN 8
Conversion of 3-Phosphoglycerate –> 2-Phosphoglycerate
Isomerization RXN
Phosphoglycerate Mutase
Mg2+ required
Reversible RXN
Energy Investment Phase: RXN 9
Conversion of 2-Phosphoglycerate –> Phosphoenolpyruvate
Dehydration RXN
Enolase
Mg2+ required
H2O released
Reversible RXN
Energy Generation Phase: RXN 10
Conversion of Phosphoenolpyruvate–> Pyruvate
Substrate level Phosphorylation
Pyruvate Kinase
Mg 2+ required
ADP is converted to ATP
Irreversible RXN
What are the fates of pyruvate?
In well oxygenated cells, most of the pyruvate generated will be converted to Acetyl-CoA and oxidised through the TCA Cycle
How is Pyruvate converted to Acetyl-CoA?
Oxidative Decarboxylation, catalysed by PDH.
