Define Cellular Respiration.

1. Define Cellular Respiration. • The process in which biomolecules, like sugar, are converted into an energy form that living things can use (ATP).

2. How many types of Cellular Respiration are there? • Two Types: Aerobic or Anaerobic • Distinguish between these. • With or without oxygen • How much ATP does each yield? • Aerobic yields 36 or 38 ATP • Anaerobic yields only 2, but gives NAD back to glycolysis to keep the process going.

3. What do cells do with the energy they get from food? • Store it as ATP or • Release as heat

4. Chemical Equations Photosynthesis: light energy converted to chemical energy • CO2 + H2O = O2 + glucose Cellular Respiration: biomolecules converted to ATP • O2 + glucose = CO2 + ATP

5. Where is the energy stored in biomolecules like sugars, carbs, lipids, etc.? • In the bonds between the atoms

6. Where in the bonds is energy stored in ATP? • In the bond between the second and third phosphate

7. How do living things access and convert the energy stored in biomolecules? • Break existing bonds and form new ones

8. What is the name for the series of reactions that converts the stored energy in biomolecules into molecules of ATP? • Cellular Respiration

9. What is the first stage of cellular respiration called? • Glycolysis • Where does this step occur? • In the Cytoplasm • Is this aerobic or anaerobic? • Anaerobic • What are the products of this step? • ATP, NADH, and 2 3-C Pyruvate molecules • What is the net production of ATP in this step? • 2 ATP’s

10. If oxygen is available where do the pyruvates go? • To the Mitochondria • What type of Cellular Respiration is this? • Aerobic

11. What happens in the Prep Step? • The pyruvates are transported into the mitochondria. • They lose a carbon (CO2 given off) • 2 carbon acetates are formed—they use NAD and Co enzyme A to become… • acetyl Co A

12. Diagram and describe the events of the prep step (pyruvate conversion) • 2 3-C pyruvate molecules are converted to… • 2 2-C acetate molecules with the production of… • 2 molecules of NADH and 2 molecules of CO2

13. Diagram the events of the Kreb’s Cycle indicating the number of NADH, FADH2, ATP, and CO2 molecules produced • The Krebs Cycle produces electron carriers a CO2 is released leaving… • 6 NADH, 2 FADH2, 2 ATP, 4 CO2

14. What is the significance of the four CO2 molecules produced in the Kreb’s Cycle? • The four carbons in the four CO2 molecules plus the two carbons in the two CO2 molecules from the prep step are evidence that the initial six carbon sugar molecule is completely broken down

15. Describe what the electron transport chain is and where it is located in the mitochondria. • The ECT is a series of protein molecules embedded on the inner membrane of the mitochondria that each have a higher attraction for electrons than the previous one.

16. What is the source of electrons to the electron transport chain? • The co-enzymes NADH and FADH2

17. Every time an electron is accepted and released by a protein in the electron transport chain –a redox reaction releases a small amount of energy used to do what? • Actively transport a H+ ion from the matrix into the outer compartment

18. What happens when a molecule is reduced? • It accepts electrons. • What happens when a molecule is oxidized? • It loses electrons. • What is this reaction called? • A Redox Reaction.

19. Mnemonic Strategy • LEO the lion says GER • Lose Electrons=Oxidize • Gain Electrons=Reduce

20. Where do H+ ions become highly concentrated? • In the Outer compartment • Are these ions freely permeable to the membrane? • No, so…how can they diffuse through the membrane into the outer compartment? • Through ATP Synthetase transport proteins.

21. Is the diffusion of H+ ions energy releasing or energy requiring? • Releasing • Is the formation of ATP from ADP energy releasing or energy requiring? • Requiring • Link these two statements in explaining the formation of ATP. • The energy released in the diffusion of H+ is required to form ATP.

22. How many ATP molecules can be created from the electrons delivered by NADH? • 3/NADH • How many ATP molecules can be created from the electrons delivered by FADH2? • 2/FADH2

23. What serves as the final electron acceptor in aerobic respiration? • Oxygen • What happens to pyruvates if oxygen is not available? • Pyruvates stay in the cytoplasm and participate in Lactic Acid Fermentation pathways.

24. Diagram the lactic acid anaerobic respiration pathway that occurs in animals • 2 3-C Pyruvates-->2 3-C Lactic Acid • 2 NAD+ molecules are produced in this step

25. What products from lactic acid fermentation are re-cycled in the respiration pathways? • NAD+ to re-start glycolysis

26. How many ATP molecules per glucose are formed in lactic acid fermentation? • 2 ATP’s/glucose

27. What kind of fermentation do yeasts and bacteria undergo? • Alcoholic fermentation

28. Why do you “feel the burn” when you are exercising strenuously? • Lactic acid fermentation • There is a build up of lactic acid in the muscles due to anaerobic lactic acid fermentation.

29. Give two reasons why muscles can’t contract well when fatigued during strenuous exercise. • 1. Only get 2 ATP per glucose due to anaerobic respiration. • 2. Lactic acid molecules build up in muscles and interfere with muscle contractions.

30. Why is it valuable that animals can respire anaerobically? • It allows animals to exert energy at a high intensity for a short period of time– times of stress for fighting or fleeing. • If we were not able to do anaerobic respiration, we would pass out when we had a decrease of oxygen

31. Compare: Photosynthesis and Cellular Respiration • Location: Where does each take place? • Photosynthesis happens on the thylakoid membrane. • Cellular respiration happens on the inner membrane of the mitochondria. • Both build up a concentration of hydrogen to power the transformation of ADP into ATP.

32. Compare -- Photosynthesis vs. Cellular respiration • Source of electrons: • Photosynthesis gets electrons from—breakdown of water molecules (photolysis). • Cellular respiration gets electrons from—FADH2 and NADH from Krebs cycle. • Final electron acceptors= NADP+ in photosynthesis and Oxygen in aerobic respiration.

33. Cycles • Photosynthesis has Calvin cycle…. adds carbon to make sugar. • Cellular Respiration has the…. • Krebs cycle--creates source of electrons and ATP for larger production of ATP

34. Compare--- Organisms that do photosynthesis and cellular respiration. • Photosynthesis happens …only in plants. • Cellular respiration in both plants and animals.

35. Review • Cellular respiration –Two basic stages: • Glycolysis and Krebs Cycle • Glycolysis yields 2 ATP • Aerobic respiration (Krebs and ECT) yields: • 36 0r 38 ATP • If no oxygen is available.. • Fermentation begins and NAD+ is recycled back into.. • Glycolysis which continues until… • Oxygen is available.

36. Review • Two kinds of fermentation: • Alcoholic and Lactic Acid • Alcoholic fermentation is done by: • Yeast, bacteria, fungus and creates foods like • Beer, wine, cheese, bread • Lactic acid fermentation happens in • animals and some fungi. It causes.. • Sore muscles after anaerobic exercise.

37. The End • Good Luck!