Biology / Unit 3: Cellular Energy
3.4 Cellular Respiration
Notes
Cellular respiration breaks down glucose to make ATP. Plants and animals both do it.
- Equation: $\text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2 \rightarrow 6\text{CO}_2 + 6\text{H}_2\text{O} + \text{ATP}$
- Glycolysis (cytoplasm): splits glucose into 2 pyruvate, making 2 ATP. Does not need oxygen.
- Krebs cycle (mitochondrial matrix): breaks pyruvate down, releasing $\text{CO}_2$.
- Electron transport chain (inner mitochondrial membrane): makes most of the ATP. Oxygen is the final electron acceptor and forms water.
- Aerobic respiration makes about 36 to 38 ATP per glucose.
Practice
Where does glycolysis take place?
Glycolysis is the first step and happens outside the mitochondria.
Which stage of cellular respiration makes the most ATP?
The electron transport chain produces most of the roughly 36 to 38 ATP.
When you breathe out, you release carbon dioxide. Where in your cells was that CO2 made?
The Krebs cycle releases carbon from pyruvate as CO2.
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