TYPES OF CELLULAR RESPIRATION
| Type of Cellular Respiration |
Description |
Oxygen Requirement |
Key Steps/Processes |
ATP Yield (per Glucose) |
| Aerobic Respiration |
Most common and efficient form of respiration. |
Requires Oxygen |
1. Glycolysis 2. Citric Acid Cycle (Krebs Cycle) 3. Electron Transport Chain |
Up to 38 ATP |
| Anaerobic Respiration |
Occurs in the absence of oxygen or in low-oxygen environments. |
Oxygen Not Required |
1. Glycolysis 2. Fermentation (e.g., lactic acid or alcoholic fermentation) |
Fewer than 38 ATP |
| Lactic Acid Fermentation |
Anaerobic process in which pyruvate is converted to lactic acid. |
No Oxygen Required |
1. Glycolysis 2. Lactic Acid Formation |
2 ATP (per glucose) |
| Alcoholic Fermentation |
Anaerobic process in which pyruvate is converted to ethanol and CO2. |
No Oxygen Required |
1. Glycolysis 2. Ethanol and CO2 Formation |
2 ATP (per glucose) |
NET GAIN OF ATP IN GLYCOLYSIS
| Glycolysis Step |
Substrate/Reactants |
Products |
ATP Produced |
ATP Consumed |
Net ATP |
| Step 1: Phosphorylation |
Glucose (1 molecule) |
Glucose-6-phosphate (2 molecules) |
2 ATP (2 ATP used) |
0 ATP |
2 ATP |
| Step 2: Isomerization |
Glucose-6-phosphate (2 molecules) |
Fructose-6-phosphate (2 molecules) |
0 ATP |
0 ATP |
2 ATP |
| Step 3: Phosphorylation |
Fructose-6-phosphate (2 molecules) |
Fructose-1,6-bisphosphate (2 molecules) |
2 ATP (2 ATP used) |
0 ATP |
2 ATP |
| Step 4: Cleavage |
Fructose-1,6-bisphosphate (2 molecules) |
Dihydroxyacetone phosphate (2 molecules) and Glyceraldehyde-3-phosphate (2 molecules) |
0 ATP |
0 ATP |
2 ATP |
| Step 5: Isomerization |
Dihydroxyacetone phosphate (2 molecules) |
Glyceraldehyde-3-phosphate (2 molecules) |
0 ATP |
0 ATP |
0 ATP |
| Step 6: Oxidation and ATP Formation |
Glyceraldehyde-3-phosphate (2 molecules) |
1,3-Bisphosphoglycerate (2 molecules) |
4 ATP (2 ATP produced, 2 ATP used) |
0 ATP |
4 ATP |
| Step 7: Phosphorylation |
1,3-Bisphosphoglycerate (2 molecules) |
3-Phosphoglycerate (2 molecules) |
0 ATP |
0 ATP |
4 ATP |
| Step 8: Isomerization |
3-Phosphoglycerate (2 molecules) |
2-Phosphoglycerate (2 molecules) |
0 ATP |
0 ATP |
4 ATP |
| Step 9: Dehydration |
2-Phosphoglycerate (2 molecules) |
Phosphoenolpyruvate (2 molecules) |
0 ATP |
0 ATP |
4 ATP |
| Step 10: Phosphorylation |
Phosphoenolpyruvate (2 molecules) |
Pyruvate (2 molecules) |
4 ATP (2 ATP produced, 2 ATP used) |
0 ATP |
4 ATP |
| Net ATP Produced in Glycolysis |
- |
- |
Total ATP Produced: 10 ATP |
Total ATP Used: 4 ATP |
Net ATP: 6 ATP |
Please note that glycolysis produces a total of 10 ATP molecules through substrate-level phosphorylation (direct ATP production) and consumes 4 ATP molecules (2 ATP used in Steps 1 and 3, and 2 ATP produced in Steps 6 and 10), resulting in a net gain of 6 ATP molecules per molecule of glucose metabolized during glycolysis.
