1. December 5, 2012Caring Requisite: required; necessary Do Now: You will read a news release. In your journal you must write your opinion and provide solid reasoning for your opinion.

2. Cellular Respiration C 6 H 12 O 6 + 6 O 2  6 CO 2 + 6H 2 O + 38 ATP

3. Cellular Respiration: An Overview Process by which cells convert the energy in food (usually glucose) into usable ATP. Terms to Know…  Oxidation = the loss of electrons Compound becomes more positive  Reduction = the gain of electrons Compound becomes more negative  Electrons and protons (H + ) travel TOGETHER  NAD + = coenzyme derived from niacin; acts as a H + and e- acceptor. AN ENERGY CARRIER!

4. Cellular Respiration: An Overview

5. Substrate-Level Phosphorylation An enzyme transfers a phosphate group directly from an organic molecule to ADP to form ATP The ATP produced in Glycolysis & the Krebs Cycle is produced by this method.

6. Oxidative Phosphorylation (ETC + Chemiosmosis) The production of ATP by using energy derived from the redox reactions of the Electron Transport Chain. The enzyme ATP synthase is needed to phosphorylate the ADP to produce ATP. Almost 90% of the ATP produced from cellular respiration is produced this way.

7. Cellular Respiration Glucose Anaerobic Respiration (Fermentation) Aerobic Respiration (Krebs Cycle & ETC) Glycolysis Oxygen AbsentOxygen Present ATP

8. Glycolysis “glucose-splitting” Big Picture:  Glucose (6-C) is broken down into 2 molecules of pyruvate (3-C) Occurs in the cytosol Occurs with or without oxygen Made up of 2 phases:  Energy investment phase  Energy yielding phase

9. Glycolysis: Energy Investment Phase Glucose is converted into 2 G3P (Glyceraldehyde-3- phosphate) Requires 2 ATP

10. Glycolysis: Energy-Yielding Phase  2 G3P are converted into 2 Pyruvate (3C) molecules.  Dehydrogenase enzymes remove H from intermediate compounds and attach them to 2 NAD to produce 2NADH

11. Net Gain in Glycolysis 2 ATP - 2 ATP (Energy investment phase) + 4 ATP (Energy yielding phase) + 2 ATP 2 NADH  Electron carriers  Will be used to make ATP later

12. Choices, Choices! If oxygen is absent, anaerobic respiration occurs  Fermentation Yeast & some bacteria  alcoholic fermentation Animal muscle  lactic acid fermentation If oxygen is present, aerobic respiration occurs  Krebs Cycle and Electron Transport Chain

13. Cellular Respiration Glucose Anaerobic Respiration (Fermentation) Aerobic Respiration Glycolysis Oxygen AbsentOxygen Present ATP

14. Fermentation 2 major types:  Alcoholic and lactic acid fermentation NAD + acts as a hydrogen acceptor during glycolysis  If the supply of NAD + runs out, then glycolysis would have to stop.  Fermentation occurs as simply a means of recycling the NAD+, so that glycolysis can occur again.

15. Alcoholic Fermentation Occurs in some BACTERIA and YEAST 2 step process:  Carbon dioxide is released from pyruvate (3-C), forming acetaldehyde (2-C)  Acetaldehyde is reduced by NADH (gains an electron), forming ethyl alcohol (ethanol)  NAD + is regenerated, thereby allowing glycolysis to continue Used to produce beer and wine

16. Lactic Acid Fermentation Occurs in ANIMALS 1 step process:  Pyruvate is reduced by NADH (gains an electron), forming lactic acid NAD + is regenerated, thereby allowing glycolysis to continue Occurs in muscle cells, causing muscle pain and fatigue

17. Cellular Respiration Glucose Anaerobic Respiration (Fermentation) Aerobic Respiration Glycolysis Oxygen AbsentOxygen Present ATP

18. Aerobic Respiration After glycolysis, most of the energy from glucose remains “locked” in 2 molecules of pyruvate If oxygen is present, the pyruvate enters the mitochondrial matrix to complete the Krebs Cycle Pyruvate (3-C) is converted to Acetyl CoA (2-C)  CO 2 is released as a waste product  NADH is produced

20. The Krebs Cycle Yield per pyruvate molecule:  4 NADH  1 FADH 2  1 ATP  2 CO 2 Yield per glucose molecule (two turns of Krebs Cycle):  8 NADH  2 FADH 2  2 ATP  6 CO2 CO 2 released as a waste product

21. Electron Transport Chain The ETC converts the NADH and FADH 2 from glycolysis and the Krebs Cycle into ATP Occurs in inner membrane of mitochondrion The energy in each NADH molecule moves enough protons (H + ) into the mitochondrial matrix to create 3 ATP 1 FADH 2  2 ATP

22. The Electron Transport Chain The electrons from NADH and FADH 2 are passed from one electron acceptor molecule to another. Each electron acceptor is more electronegative than the last. Oxygen is the final electron acceptor e- ETC oxygen

23. Chemiosmosis Similarly to photosynthesis, the energy the electrons lose along the way moves H + out of the matrix and into the intermembrane space of the mitochondrion As H + ions diffuse through the membrane, ATP synthase uses the energy to join ADP and a phosphate group  ATP

24. Oxidative Phosphorylation: ETC & Chemiosmosis

25. Aerobic Respiration: Total Energy Yield Glycolysis:  2 ATP (Net)  2 NADH  6 ATP Krebs Cycle:  2 ATP  8 NADH  24 ATP (ETC)  2 FADH 2  4 ATP (ETC) TOTAL:  8 ATP + 30 ATP  38 ATP