The document discusses cellular respiration, which is how cells acquire energy from breaking down nutrients. It has three main stages: glycolysis, the citric acid cycle, and the electron transport chain. Glycolysis occurs in the cytoplasm and produces 2 ATP per glucose molecule. The citric acid cycle occurs in the mitochondria and produces 2 more ATP plus electron carriers. The electron transport chain also occurs in the mitochondria and produces the majority of ATP, around 32-34 molecules per glucose. The overall process of cellular respiration produces about 36 ATP.

1. Chapter 7 Deriving Energy From Food

3. Both plants and animals perform cellular respiration. The waste products of cellular respiration, CO 2 and H 2 O, are used in photosynthesis.

4. Storing and Releasing Energy Where Does The Energy Come From? Figure 7.1

5. Redox Reactions – pg. 125 Oxidation-reduction (redox) reactions: Electrons pass from one molecule to another The molecule that loses an electron is oxidized The molecule that gains an electron is reduced Both take place at same time One molecule accepts the electron given up by the other

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7. Cellular Respiration – pg. 127 Cellular respiration is the process by which cells acquire energy by breaking down nutrient molecules chemical energy is harvested from food and converted to ATP. Consumes oxygen and produces carbon dioxide Is an aerobic process (pg. 127)

8. Cellular Respiration Overview Stages of Cellular Respiration: Glycolysis (“sugar splitting”) 2. Citric Acid Cycle (Krebs Cycle) 3. Electron Transport Chain (ETC)

9. Stage 1: Glycolysis Glycolysis means “splitting of sugar” Takes place in the cytoplasm A molecule of glucose (C 6 ) is split into two molecules of pyruvate (pyruvic acid C 3 ). 2 ATP produced per glucose six-carbon glucose Three-carbon pyruvic acid

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11. Stage 2: Krebs Cycle Occurs in the mitochondria – aerobic process Turns twice per glucose molecule (one for each pyruvate) Forms coenzymes NADH and FADH 2 which serve as electron carriers = 2 ATP (one per acetic acid) Also known as the Citric Acid Cycle

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13. Stage 3: Electric Transport Chain (ETC) Electron transport releases the energy your cells need to make most of their ATP Occurs in the mitochondria Creates a H + gradient = As the electrons are passed between carrier proteins through the chain, energy is released in the form of ATP Oxygen serves as the final electron acceptor Movement of electrons = 32 – 34 ATP

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15. Cellular Respiration Overview Stages of Cellular Respiration: Glycolysis Occurs in the cytoplasm Glucose to 2 pyruvate = 2 ATP Krebs Cycle (Citric Acid Cycle) Occurs in the mitochondria Coenzymes NADH and FADH 2 = 2 ATP Electron Transport Chain (ETC) Occurs in the mitochondria Movement of electrons = 32 – 34 ATP

17. ATP from Cellular Respiration

18. Overall Energy Yield Net yield per glucose: From glycolysis – 2 ATP From citric acid cycle – 2 ATP From electron transport chain – 32 or 34 ATP Energy content: Energy yield (36 ATP) 263 kcal Efficiency is 39% The rest of the energy from glucose is lost as heat

19. Fermentation: Anaerobic Respiration If O 2 is not available to the cell, fermentation , an anaerobic process , occurs in the cytoplasm. During fermentation, glucose is incompletely metabolized to lactate, or to CO 2 and alcohol (depending on the organism). – pg. 130 Yields 2 ATP

20. FERMENTATION Lactic Acid Fermentation Happens in muscle cells Lactic acid Alcohol Fermentation Happens in some bacteria and YEAST brewing, wine making, and baking ethyl alcohol & CO2 http://videos.howstuffworks.com/discovery/34874-howstuffworks-show-episode-5-fermentation-video.htm

22. Metabolic Pool Foods are sources of energy rich molecules such as carbohydrates, fats, and proteins Degradative reactions ( catabolism ) break down molecules Tend to be exergonic (release energy) Synthetic reactions ( anabolism ) build molecules Tend to be endergonic (consume energy)

24. Comparing Aerobic & Anaerobic Cellular Respiration Pathways **NOTICE – Aerobic respiration is more efficient!! 2 36 Net ATP production: Ethanol + CO 2 or lactic acid 6 CO 2 + 6 H 2 O 1 glucose makes: Mostly yeast and bacteria Most organisms Occurs in: Anaerobic Aerobic

25. Comparing Photosynthesis & Respiration C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O 6CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 2 Equation CO 2 and H 2 O C 6 H 12 O 6 and O 2 Products C 6 H 12 O 6 and O 2 CO 2 and H 2 O Reactants Mitochondria Chloroplasts Location Energy Release Energy Storage Function Cellular Respiration Photosynthesis