1 Chapter 8 Cellular Respiration: Harvesting Chemical Energy Harvesting Chemical Energy

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<ul><li> Slide 1 </li> <li> 1 Chapter 8 Cellular Respiration: Harvesting Chemical Energy Harvesting Chemical Energy </li> <li> Slide 2 </li> <li> 2 Aerobic metabolism - When enough oxygen reaches cells to support energy needs - Maximum energy production - Maximum energy production Anaerobic metabolism When the demand for oxygen outstrips the bodys ability to deliver it Low energy production Aerobic &amp; Anaerobic Metabolism </li> <li> Slide 3 </li> <li> 3 Cellular respiration is the main way that chemical energy is harvested from food and converted to ATP for cellular work Cellular respiration is an aerobic process requiring oxygen AEROBIC HARVEST OF FOOD ENERGY </li> <li> Slide 4 </li> <li> 4 The Versatility of Cellular Respiration Cellular respiration can burn other kinds of molecules besides glucose: Diverse types of carbohydrates FatsProteins </li> <li> Slide 5 </li> <li> 5 A common fuel molecule for cellular respiration is glucose This is the overall equation for what happens to glucose during cellular respiration The Overall Equation for Cellular Respiration GlucoseOxygenCarbon dioxideWaterEnergy </li> <li> Slide 6 </li> <li> 6 But Remember Cellular Respiration is a metabolic pathway, not a single reaction Many chemical reactions, both aerobic and anaerobic, are involved in the process of cellular respiration Lots of enzymes are required for the process to occur </li> <li> Slide 7 </li> <li> 7 Cellular respiration and breathing are closely related Cellular respiration requires a cell to exchange gases with its surroundings Breathing exchanges these gases between the blood and outside air The Relationship Between Cellular Respiration and Breathing </li> <li> Slide 8 </li> <li> 8 During cellular respiration, hydrogen and its bonding electrons change partners Hydrogen and its electrons go from sugar to oxygen, forming water The Role of Oxygen in Cellular Respiration </li> <li> Slide 9 </li> <li> 9 Comparison RespirationPhotosynthesis Occurs in all organisms Occurs in only chlorophyll containing organisms Breaks down glucose Stores light energy as chemical energy in the bonds of glucose Releases carbon dioxide, water, &amp; ATP Produces glucose and oxygen Exergonic Reaction Endergonic reaction </li> <li> Slide 10 </li> <li> 10 All of the reactions involved in cellular respiration can be grouped into three main stages Glycolysis occurs in cytoplasm The Krebs cycle occurs in matrix of mitochondria Electron transport occurs across the mitochondrial membrane The Metabolic Pathway of Cellular Respiration </li> <li> Slide 11 </li> <li> 11 A Road Map for Cellular Respiration Cytosol Mitochondrion High-energy electrons carried by NADH High-energy electrons carried mainly by NADH Glycolysis Glucose 2 Pyruvic acid Krebs Cycle Electron Transport </li> <li> Slide 12 </li> <li> 12 Glycolysis Stage One </li> <li> Slide 13 </li> <li> 13 Glycolysis takes place in the cytoplasm Oxygen NOT required Process breaks a six-carbon glucose into two, three-carbon molecules Process breaks a six-carbon glucose into two, three-carbon molecules A molecule of glucose is split into two molecules of pyruvic acid These molecules then donate high energy electrons to NAD+, forming NADH Stage 1: Glycolysis </li> <li> Slide 14 </li> <li> Glycolysis 14 Glucose 2 Pyruvic acid METABOLIC PATHWAY </li> <li> Slide 15 </li> <li> 15 CoA Pyruvic acid Acetic acid Coenzyme A Acetyl-CoA (acetyl-coenzyme A) CO 2 Glycolysis </li> <li> Slide 16 </li> <li> Krebs Cycle Stage Two 16 </li> <li> Slide 17 </li> <li> 17 Stage 2: The Krebs Cycle The Krebs cycle completes the breakdown of sugar It occurs inside the mitochondria In the Krebs cycle, pyruvic acid from glycolysis is first prepped into a usable form by combining it with enzyme Co-A to make Acetyl-CoA </li> <li> Slide 18 </li> <li> Input Acetic acid ADP 3 NAD FAD Krebs Cycle Output 2 CO 2 1 2 3 4 5 6 ACETYL Co-A </li> <li> Slide 19 </li> <li> Electron Transport Stage 3 </li> <li> Slide 20 </li> <li> 20 Stage 3: Electron Transport Electron transport releases the energy your cells need to make the most of their ATP The molecules of electron transport chains are built into the inner membranes of mitochondria </li> <li> Slide 21 </li> <li> 21 Stage 3: Electron Transport The chain functions as a chemical machine that uses energy released by the fall of electrons to pump hydrogen ions across the inner mitochondrial membrane These ions store potential energy </li> <li> Slide 22 </li> <li> 22 Electron transport chain Cytochromes carry electron carrier molecules (NADH &amp; FADH 2 ) down to oxygen Chemiosmosis: energy coupling mechanism ATP synthase: produces ATP by using the H+ gradient (proton-motive force) pumped into the inner membrane space from the electron transport chain; this enzyme harnesses the flow of H+ back into the matrix to phosphorylate ADP to ATP (oxidative phosphorylation) </li> <li> Slide 23 </li> <li> 23 Protein complex Electron carrier Inner mitochondrial membrane Electron flow Electron transport chain ATP synthase </li> <li> Slide 24 </li> <li> 24 Food Polysaccharides FatsProteins SugarsGlycerolFatty acidsAmino acids Amino groups Glycolysis Acetyl- CoA Krebs Cycle Electron Transport </li> <li> Slide 25 </li> <li> 25 Adding Up the ATP Figure 6.14 Cytosol Mitochondrion Glycolysis Glucose 2 Pyruvic acid 2 Acetyl- CoA Krebs Cycle Electron Transport by direct synthesis by direct synthesis by ATP synthase Maximum per glucose: </li> <li> Slide 26 </li> <li> 26 FERMENTATION: ANAEROBIC HARVEST OF FOOD ENERGY Some of your cells can actually work for short periods without oxygen (anaerobic respiration) For example, muscle cells can produce ATP under anaerobic conditions Called Fermentation Involves The anaerobic harvest of food energy </li> <li> Slide 27 </li> <li> 27 Human muscle cells can make ATP with and without oxygen They have enough ATP to support activities such as quick sprinting for about 5 seconds A secondary supply of energy (creatine phosphate) can keep muscle cells going for another 10 seconds To keep running, your muscles must generate ATP by the anaerobic process of fermentation Fermentation in Human Muscle Cells </li> <li> Slide 28 </li> <li> 28 Glycolysis is the metabolic pathway that provides ATP during fermentation Pyruvic acid is reduced by NADH, producing NAD+, which keeps glycolysis going In human muscle cells, lactic acid is a by-product </li> <li> Slide 29 </li> <li> 29 2 ADP+ 2 Glycolysis Glucose 2 NAD 2 Pyruvic acid + 2 H 2 NAD 2 Lactic acid Lactic acid fermentation </li> <li> Slide 30 </li> <li> Various types of microorganisms perform fermentation Yeast cells carry out a slightly different type of fermentation pathway This pathway produces CO 2 and ethyl alcohol Fermentation in Microorganisms </li> <li> Slide 31 </li> <li> 31 2 ADP+ 2 2 ATP Glycolysis Glucose 2 NAD 2 Pyruvic acid 2 CO 2 released + 2 H 2 NAD 2 Ethyl alcohol Alcoholic fermentation </li> <li> Slide 32 </li> <li> 32 The food industry uses yeast to produce various food products </li> <li> Slide 33 </li> <li> 33 Related metabolic processes Fermentation: alcohol~ pyruvate to ethanol lactic acid~ pyruvate to lactate Facultative anaerobes (yeast/bacteria) </li> <li> Slide 34 </li> <li> 34 Review: Cellular Respiration Glycolysis: 2 ATP (substrate-level phosphorylation) Krebs Cycle: 2 ATP (substrate-level phosphorylation) Electron transport &amp; oxidative phosphorylation: 2 NADH (glycolysis) = 6ATP 2 NADH (acetyl CoA) = 6ATP 6 NADH (Krebs) = 18 ATP 2 FADH2 (Krebs) = 4 ATP 38 TOTAL ATP/glucose </li> <li> Slide 35 </li> <li> 35 </li> <li> Slide 36 </li> <li> 36 Sunlight energy Ecosystem Photosynthesis (in chloroplasts) Glucose Oxygen Carbon dioxide Cellular respiration (in mitochondria) Water Cellular energy Heat energy Sunlight supplies the energy! Bonds of Glucose, made in chloroplasts, contain the stored energy Raw materials for photosynthesis Raw materials for cellular respiration Glucose broken down to release energy for cellular work </li> </ul>

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