The Four Stages in Aerobic Respiration
- Glucose is the main respiratory substrate used by cells
- Aerobic respiration is the process of breaking down a respiratory substrate in order to produce ATP using oxygen
- The process of aerobic respiration using glucose can be split into four stages
- Each stage occurs at a particular location in a eukaryotic cell:
- Glycolysis takes place in the cell cytoplasm
- The Link reaction takes place in the matrix of the mitochondria
- The Krebs cycle takes place in the matrix of the mitochondria
- Oxidative phosphorylation occurs at the inner membrane of the mitochondria
Four Stages of Respiration Table
| Stage | Description | Location |
| 1. Glycolysis | Phosphorylation and splitting of glucose | Cell cytoplasm |
| 2. Link reaction | Decarboxylation and dehydrogenation of pyruvate | Mitochondrial matrix |
| 3. Krebs cycle | Cyclical pathway with enzyme-controlled reactions | Mitochondrial matrix |
| 4. Oxidative phosphorylation | Production of ATP through oxidation of hydrogen atoms | The inner membrane of mitochondria |
Examiner Tip
It’s important to know the exact locations of each stage. It is not enough to say the Krebs cycle takes place in the mitochondria, you need to say it takes place in the matrix of the mitochondria.
