1. The Krebs Cycle & Electron Transport

2. Cellular Respiration Cellular Respiration: energy- releasing pathways within a cell. Because the pathways require oxygen, they are aerobic.

3. History of Krebs Cycle The cycle is named after Hans Krebs, a British scientist who demonstrated its existence. The cycle is also known as the citric acid cycle because citric acid is the first compound formed.

4. The Krebs Cycle Pyruvate from glycolysis passes to the Krebs Cycle. Pyruvate is broken down into CO 2. High-energy electrons are passed to NADH & FADH 2. The electrons pass to the electron transport chain. The electron transport chain converts ADP to ATP. H 2 O & CO 2 are produced as wastes.

5. How much energy is produced from a glucose molecule? Glycolysis: 2 ATP Electron Transport: 34 ATP Total: 36 ATP

6. Efficiency of Cycle The 36 ATP is 38% of glucose's total energy. The remaining 62% is released as heat. This is more efficient than a car’s engine.

7. ATP in Cells Cells store a small amount of ATP. When more energy is needed, ATP is produced by lactic acid fermentation. (in a race or exercising) Lactic acid is a by-product, which causes sore muscle.

8. Photosynthesis & Cellular Respiration Photosynthesis: deposits energy. Cellular respiration: withdraws energy.

9. Comparing Photosynthesis and Cellular Respiration PhotosynthesisCellular Respiration Function Capture EnergyRelease Energy Location ChloroplastsMitochondria Reactants CO 2 and H 2 OC 6 H 12 O 6 and O 2 Products C 6 H 12 O 6 and O 2 CO 2 and H 2 O Equation 6CO 2 + 6H 2 O → C 6 H 12 O 6 + 6O 2 ↑ ENERGY C 6 H 12 O 6 + 6O 2 → 6CO 2 + 6H 2 O ↓ ENERGY