2. 2009-2010 Cellular Respiration Harvesting Chemical Energy ATP

3. Section Objectives: Compare and contrast cellular respiration and fermentation. Explain how cells obtain energy from cellular respiration. Ch.8.3

4. Harvesting energy stored in food Cellular respiration – breaking down food to produce ATP in mitochondria using oxygen – “aerobic” respiration – usually digesting glucose but could be other sugars, fats, or proteins C 6 H 12 O 6 6O 2 ATP6CO 2 6H 2 O  + ++ glucose + oxygen  energy + carbon + water dioxide O2O2 food ATP

5. What do we need to make energy? The “Furnace” for making energy – mitochondria Fuel – food: carbohydrates, fats, proteins Helpers – oxygen – enzymes Product – ATP Waste products – carbon dioxide then used by plants – water O2O2 food ATP Make ATP! Make ATP! All I do all day… And no one even notices! enzymes CO 2 H2OH2O

6. Mitochondria are everywhere!! animal cells plant cells

7. Can’t store ATP  too unstable  only used in cell that produces it  only short term energy storage  carbohydrates & fats are long term energy storage Using ATP to do work? A working muscle recycles over 10 million ATPs per second ATP ADP work Whoa! Pass me the glucose & oxygen! Adenosine DiPhosphate Adenosine TriPhosphate

8. make energy A Body’s Energy Budget eat food synthesis (building) energy needed even at rest activity temperature control { growth reproduction repair { storage glycogen (animal starch) fat { ATP 1 2 3

9. Cellular Respiration The first stage, glycolysis, is anaerobic—no oxygen is required. The last two stages are aerobic and require oxygen to be completed. SUMMARY EQUATION:

10. STAGES OF CELLULAR RESPIRATION Respiration occurs in three main stages GLYCOLYSISKREBS CYCLE ELECTRON TRANSPORT CHAIN High-energy electrons carried by NADH Mitochondrion Cytoplasmic fluid

11. Glycolysis [Glyco=sweet, sugar lysis = to split] s: a series of chemical reactions in the cytoplasm of a cell that break down glucose, a six-carbon compound, into two molecules of pyruvic acid, a three-carbon compound produces only two ATP molecules for each glucose molecule broken down. (4-2=2) 2 molecules of NADH are formed Glucose 2 Pyruvic acid 2ATP2ADP4ADP + 4P 4ATP 2NAD+ 2NADH + 2H+

12. Transition Phase. Before citric acid cycle and electron transport chain can begin, pyruvic acid undergoes a series of reactions in which it gives off a molecule of CO 2 and combines with a molecule called coenzyme A to form acetyl-CoA. Pyruvic acid Acetyl CoA (acetyl coenzyme A) CO2

13. The citric acid cycle also called the Krebs cycle, is a series of chemical reactions in that the molecule used in the first reaction is also one of the end products. For every turn of the cycle, one molecule of ATP and two molecules of carbon dioxide, 3 NADH, 1 FADH 2 are produced. For a total of 2ATP,6 NADH,& 2 FADH 2 Occurs in mitochondrial matrix CO2

14. The electron transport chain In the electron transport chain, the carrier molecules NADH and FADH 2 gives up electrons that pass through a series of reactions. Oxygen is the final electron acceptor forming water. This sets up a H+ (proton) gradient Allow the protons to flow through ATP synthase which synthesizes ATP (ADP + Pi = ATP) the electron transport chain adds 32 ATP molecules to the four already produced during glycolysis & citric acid cycle Occurs in the inner mitochondrial membrane occurs

15. What if oxygen is missing? No oxygen available = can’t complete aerobic respiration Anaerobic respiration – also known as fermentation alcohol fermentation lactic acid fermentation – no oxygen or no mitochondria (bacteria) – can only make very little ATP – large animals cannot survive O2O2 yeast bacteria

16. Anaerobic Respiration Fermentation – alcohol fermentation yeast – glucose  ATP + CO 2 + alcohol – make beer, wine, bread – lactic acid fermentation bacteria, animals – glucose  ATP + lactic acid – bacteria make yogurt – animals feel muscle fatigue O2O2 Tastes good… but not enough energy for me!

17. Alcoholic fermentation used by yeast cells and some bacteria to produce CO 2 and ethyl alcohol glucose -> pyruvic acid-> 2 ethyl alcohol + 2 CO2 2ATP 2ATP GLYCOLYSIS FERMENTATION GLYCOLYSIS FERMENTATION

18. Lactic acid fermentation Glucose->pyruvic acid -> 2 lactic acid 2ATP GLYCOLYSIS FERMENTATION used to make cheese and yogurt ~ in humans during strenuous exercise not enough oxygen from blood “oxygen debt” ~ lactic acid accumulates in muscle; leads to fatigue and pain Will be converted back to pyruvic acid in liver

19. Got the energy… Ask Questions!!

20. Compare & Contrast Photosynthesis & Cell Respiration Photosynthesis Cell Respiration