The Process of Cellular Respiration

1. The Process of Cellular Respiration

2. Learning Objectives • Describe what happens during glycolysis. • Describe what happens during the Krebs cycle. • Explain how high-energy electrons are used by the electron transport chain. • Identify how much ATP cellular respiration generates.

3. Photosynthesis and Cellular Respiration Photosynthesis and cellular respiration can be thought of as opposite processes. Why?? What do you think Goes in and comes out? Where in the cell do you Think cellular respiration takes place?

4. Cellular Respiration The chemical summary of cellular respiration is: What does the equation look like expressed in symbols?

5. Energy Storing Molecules: ATP, NADPH (NAD+), FADH (FAD+), FADH2 ATP supplies most of the energy that drives metabolism in living things ATP releases energy when converted into ADP Energy Review

6. Living things get most of the energy they need from glucose. Autotrophs make glucose using photosynthesis Heterotrophs get glucose from food they eat Cellular Respiration The process that releases energy by breaking down glucose and other food molecules in the presence of oxygen. Cellular Respiration OverviewChapter 9

7. Figure 9–2 Cellular Respiration: An Overview Mitochondrion Electrons carried in NADH Electrons carried in NADH and FADH2 Pyruvic acid Glucose Electron Transport Chain Krebs Cycle Glycolysis Mitochondrion Cytoplasm

8. 3 Stages of Cellular Respiration Glycolysis Krebs cycle Electron transport Main source of energy produced= ATP!!!!

9. Glycolysis • Glyco = Glucose • lysis = Breakdown • Occurs in the cytoplasm of the cell • One molecule of glucose is converted to two molecules of pyruvic acid.

10. Glycolysis: ATP and NADH Production Cell must use (invest) 2 ATP Produces Energy Carrier Molecules 4 ATP 2 NADH And 2 Pyruvic acid

11. The End Result of Glycolysis 4 ATP molecule used for energy 2 NADH molecules Electron carriers to ETC 2 Pyruvic Acid Krebs Cycle

12. After step 1 • After this step there is a fork in the road • If oxygen is present…. • If no oxygen…. • Lets explore one option today

13. The Krebs Cycle Pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions. • Aerobic Process = Only occurs if oxygen is present!! • Occurs in the MATRIX of the mitochondria (the maze)

14. The Krebs Cycle Pyruvic acid from glycolysis is used to make NADH, ATP, and FADH2, with carbon dioxide as a by-product. 1 ATP 3 NADH 1 FADH2 CO2

15. The Krebs Cycle: Energy Extraction For each turn of the cycle, a molecule of ADP is converted to a molecule of ATP.

16. The End Result of the Krebs Cycle 1 ATP molecule used for energy 3 NADH molecules Electron carriers to ETC 1 FADH2 molecule Electron carrier CO2 Byproduct

17. Electron Transport Products from the Krebs cycle and glycolysis feed into the last step of cellular respiration- NADH and FADH2 • Occurs in the folds of the Inner Membrane of the Mitochondria • The electrons are passed down a chain of proteins until they reach the final electron acceptor…..oxygen! • So this step is aerobic (requires oxygen)

18. Electron Transport Electron transport chain is composed of a series of electron carriers located in the inner membrane of the mitochondrion.

19. Electron Transport Electron transport uses the high-energy electrons from glycolysis and the Krebs cycle to synthesize ATP from ADP.

20. Total ATP from Cellular Respiration Glycolysis, the Krebs cycle, and the electron transport chain release about 36 molecules of ATP per molecule of glucose. 2 Total ATP? 2 30 to 42 CO2 32