2. Chap 9. Cell Respiration

3. Why is cell respiration so necessary ? Living cells need a constant supply of energy Examples: heart cells beating, muscle cells contracting, cells being made and repaired, etc. Organisms take food & break it down into glucose (mostly in the small intestine) cell respiration – process of breaking down glucose in the presence of O 2 to release energy - Done by eukaryotes!

4. Equation for Cell Resp. 6O 2 + C 6 H 12 O 6 → 6CO 2 + 6H 2 O + energy The energy that is released is used to make ATP

5. How Does It Happen? Glucose – simple sugar (C 6 H 12 O 6 ) Glucose is present in food Food is broken down by our digestive systems The chemical bonds in food are broken & the energy is released (Exergonic!) 2 major types of organisms getting energy: 1. aerobic respiration. – with O 2 2. anaerobic fermentation – without O 2

6. Review of ATP-ADP Cycle

7. Cell Respiration Step 1 – Glycolysis: Takes place in Cytoplasm A.Process of 1 molecule of glucose broken in half B.Two 3-carbon compounds produced; each called pyruvic acid C.4 ATP molecules are produced D.2 ATP molecules are used for the reaction to occur E. Net gain of ATP molecules = 2

8. Glycolysis – Cont. Each electron carrier (NAD+ or uncharged battery) accepts high- energy electrons from H & carries them to the next reaction NADH is now the charged battery

9. Review of Glycolysis Glycolysis Converts 1 glucose (C6) to 2 pyruvic acids (C3) Produces : 2 pyruvic acids 2 NADH 2 ATP (net) Occurs in cytoplasm [anaerobic] –all organisms do glycolosis

10. Aerobic Respiration Needs Mitochondria! The Krebs Cycle and Electron Transport chain take place here!

11. Cell Respiration AEROBIC! Step 2 – Krebs Cycle (Citric Acid Cycle) A.Pyruvic acid is broken down in a series of reactions B.Also called the citric acid cycle b/c citric acid is the 1 st compound produced C.CO 2, 8NADH, 2FADH 2 & 2 ATPs are produced Takes place in the mitochondria matrix The matrix is inside the inner membrane http://highered.mheducation.com/sites/0072507470/student_view0/cha pter25/animation__how_the_krebs_cycle_works__quiz_1_.htmlhttp://highered.mheducation.com/sites/0072507470/student_view0/cha pter25/animation__how_the_krebs_cycle_works__quiz_1_.html

13. Cell Respiration AEROBIC! Step 3 – Electron Transport Chain Takes place in the mitochondria inner membrane Uses high-energy electrons carried from NADH + FADH2 in the Krebs Cycle The ETC produces 32 ATP molecules, H2O, and un-charges electron carriers

14. Electron Transport Chain (ETC) - Uses high-energy electrons from the Krebs cycle to convert ADP into ATP. -Occurs along the inner membrane of the mitochondria. -The electrons from NADH & FADH 2 are passed along a series of proteins. -This movement of electrons pumps H + ions into the inner membrane space.

15. -The H + ions will move from high to low concentration through the enzyme ATP Synthase. -This movement causes the enzyme to move like a turbine and bind ADP to P forming ATP. http://highered.mheducation.com/olcweb/cg i/pluginpop.cgi?it=swf::535::535::/sites/d l/free/0072437316/120071/bio11.swf::Elec tron%20Transport%20System%20and%2 0ATP%20Synthesis

16. Why does it need oxygen? Oxygen is the final electron acceptor!

17. Electron Transport Chain

18. Where are the electrons moving?__________________ Where are the H+ ions in a high concentration?_______ When the electrons are finished going through the chain, what is the final electron acceptor?________, with H+ ions, it turns into ________. The enzyme that make ATP is _________________.

19. Totals of Aerobic Respiration - With aerobic respiration, a total of 36 ATPs are produced per glucose.

20. Comparing Photo & Cell Respiration PhotosynthesisCell Respiration Energy goes in and is stored Energy comes out Occurs in chloroplastsOccurs in mitochondria Raw materials – CO 2 & H 2 O Raw materials – glucose & O 2 Products – glucose & O 2 Products – ATP, CO 2 & H 2 O

21. Review of Glycolysis Glycolysis Converts 1 glucose (C6) to 2 pyruvic acids (C3) Produces : 2 pyruvic acids 2 NADH 2 ATP (net) Occurs in cytoplasm [anaerobic]

22. Cell Respiration When O 2 is not present gylcolysis is followed by a different path A. Fermentation The release of energy from food in the absence of O 2 – It allows the cells to continue glycolysis because it frees up NAD+ (NADH -> NAD+) B.Two types: C. alcoholic fermentation D. lactic acid fermentation

23. Types of Fermentation 1. Alcoholic Fermentation A. NADH is converted back to NAD+ and energy B. Occurs in yeast cells; used in baking bread (CO 2 makes bread rise) & in making alcohol equation: pyruvic acid + NADH → alcohol + CO 2 + NAD+

24. Types of Fermentation 2. Lactic Acid Fermentation – A.Occurs in muscle cells when they run out of O 2 B.Causes pain & soreness equation : pyruvic acid + NADH → lactic acid +NAD+ Also occurs in bacteria cells, we use it to make yogurt, sauerkraut, and kimchi

25. One more thing! The only way to get rid of your lactic acid after a hard workout is through a pathway that requires extra oxygen. That is why you breathe heavy after working out – to repay the oxygen debt.