GLYCOLYSIS PATHWAY.
Glycolysis is the metabolic pathway that breaks down glucose to produce energy.
PLACE-
It occurs in the cytoplasm of cells and can function both aerobically and anaerobically.
Here’s a simplified overview of the glycolysis pathway, which consists of ten enzyme-catalyzed reactions:
Overview of Glycolysis:
1.Glucose → Glucose-6-Phosphate
*Enzyme:Hexokinase.
*ATP used: 1
2.Glucose-6-Phosphate → Fructose-6-Phosphate
*Enzyme: Phosphoglucose isomerase.
3.Fructose-6-Phosphate → Fructose-1,6-Bisphosphate
*Enzyme: Phosphofructokinase-1 (PFK-1)
*ATP used: 1 (Key regulatory step).
4.Fructose-1,6-Bisphosphate → Glyceraldehyde-3-Phosphate + Dihydroxyacetone Phosphate
*Enzyme: Aldolase.
5.Dihydroxyacetone Phosphate → Glyceraldehyde-3-Phosphate
*Enzyme: Triose phosphate isomerase.
6.Glyceraldehyde-3-Phosphate → 1,3-Bisphosphoglycerate.
*Enzyme: Glyceraldehyde-3-phosphate dehydrogenase
*NAD+ reduced to NADH
7. 1,3-Bisphosphoglycerate → 3-Phosphoglycerate
*Enzyme: Phosphoglycerate kinase
*ATP produced: 1 (substrate-level phosphorylation)
8. 3-Phosphoglycerate → 2-Phosphoglycerate
Enzyme: Phosphoglycerate mutase.
9. 2-Phosphoglycerate → Phosphoenolpyruvate
Enzyme: Enolase.
10. Phosphoenolpyruvate → Pyruvate
Enzyme: Pyruvate kinase
ATP produced: 1 (substrate-level phosphorylation).
Key Outputs of Glycolysis:
*Net ATP: 2 ATP (4 produced, 2 used)
*NADH: 2 NADH
*Pyruvate: 2 molecules of pyruvate
Importance of Glycolysis:
Energy Production: Provides ATP for cellular processes.
*Precursor for Other Metabolic Pathways: Pyruvate can enter the Krebs cycle (aerobic) or be converted to lactate (anaerobic).
*Regulation: Key enzymes (like PFK-1) are tightly regulated, responding to cellular energy levels.
*Glycolysis is a important step in cellular respiration, providing both energy and intermediates for various biosynthetic pathways.
