Glycolysis – First Step in Cellular Respiration
(Also known as the breakdown of glucose)
Location: Cytoplasm
Main Purpose: To break down glucose and produce ATP, NADH, and pyruvate
Steps (Simplified)
1. Glucose → Glucose-6-phosphate (uses 1 ATP)
2. Glucose-6-phosphate → Fructose-6-phosphate
3. Fructose-6-phosphate → Fructose-1,6-bisphosphate (uses 1 ATP)
4. Fructose-1,6-bisphosphate → G3P (x2)
5. G3P → 1,3-Bisphosphoglycerate + NADH (x2)
6. 1,3-BPG → 3-Phosphoglycerate + ATP (x2)
7. 3-Phosphoglycerate → 2-Phosphoglycerate
8. 2-Phosphoglycerate → Phosphoenolpyruvate (PEP)
9. PEP → Pyruvate + ATP (x2)
Key Outputs (per glucose)
✅ 2 Pyruvate
✅ 2 ATP (Net Gain : 4 produced - 2 used)
✅ 2 NADH
Fact:
Glycolysis doesn’t require oxygen and is the only ATP source in anaerobic
conditions. It's the foundation of both aerobic and anaerobic respiration
(Also known as the breakdown of glucose)
Location: Cytoplasm
Main Purpose: To break down glucose and produce ATP, NADH, and pyruvate
Steps (Simplified)
1. Glucose → Glucose-6-phosphate (uses 1 ATP)
2. Glucose-6-phosphate → Fructose-6-phosphate
3. Fructose-6-phosphate → Fructose-1,6-bisphosphate (uses 1 ATP)
4. Fructose-1,6-bisphosphate → G3P (x2)
5. G3P → 1,3-Bisphosphoglycerate + NADH (x2)
6. 1,3-BPG → 3-Phosphoglycerate + ATP (x2)
7. 3-Phosphoglycerate → 2-Phosphoglycerate
8. 2-Phosphoglycerate → Phosphoenolpyruvate (PEP)
9. PEP → Pyruvate + ATP (x2)
Key Outputs (per glucose)
✅ 2 Pyruvate
✅ 2 ATP (Net Gain : 4 produced - 2 used)
✅ 2 NADH
Fact:
Glycolysis doesn’t require oxygen and is the only ATP source in anaerobic
conditions. It's the foundation of both aerobic and anaerobic respiration
