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Cellular Respiration ch 8 Slide 2 Cellular Respiration Have you ever wondered why exactly you need to breathe? What happens when you stop breathing? Slide 3 Cellular respiration is the set of the metabolic reactions and processes that take place in the cells of organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products. Mitochondria! Slide 4 C 6 H 12 O 6 + 6O 2 -->6 CO 2 + 6H 2 O + 36 ATP Slide 5 How are they connected? glucose + oxygen carbon + water + energy dioxide C 6 H 12 O 6 6O 2 6CO 2 6H 2 O ATP +++ Heterotrophs + water + energy glucose + oxygen carbon dioxide 6CO 2 6H 2 O C 6 H 12 O 6 6O 2 light energy +++ Autotrophs making energy & organic molecules from light energy making energy & organic molecules from ingesting organic molecules Where s the ATP? oxidation = exergonic reduction = endergonic Slide 6 O 2 or no O 2 Aerobic Respiration: requires oxygen (air) (breathing) Anaerobic Respiration: does not need oxygen (no air) (breathing) Slide 7 AEROBIC = with oxygen, occurs in the presence of oxygen - in mitochondira Without oxygen, another path is taken....this path is called fermentation, or Anaerobic = without oxygen, in cytosol Slide 8 There are three stages 1. Glycolysis 2. Kreb's Cycle (Citric Acid Cycle) 3. Electron Transport Chain Slide 9 net yield of 2 ATP per glucose molecule net yield of 2 NADH per glucose molecule GLYCOLYSIS GLYCOLYSIS = "glyco - lysis " is the splitting of a 6 carbon glucose into two pyruvates, each having 3 carbons can occur without oxygen Slide 10 QOD 1.What does cellular respiration produce? 2.Does it need light? 3.What does anaerobic mean? 4.What does aerobic mean? 5.What is the equation for cellular respirations? Slide 11 Stage 1: Glycolysis: Anaerobic = no O 2 needed Occurs in cytoplasm Occurs in all organisms Net of 2ATP Products: 2 ATP 2 NADH 2 Pyruvic Acids Slide 12 Stage 1: Glycolysis: Anaerobic = no O 2 needed Occurs in cytoplasm Occurs in all organisms Net of 2ATP Products: 2 ATP 2 NADH 2 Pyruvic Acids Slide 13 Equation for Cellular Respiration: oxidation & reduction REDOX reactions in respiration release energy as breakdown organic molecules break C-C bonds strip off electrons from C-H bonds by removing H atoms C 6 H 12 O 6 CO 2 = the fuel has been oxidized electrons attracted to more electronegative atoms in biology, the most electronegative atom? O 2 H 2 O = oxygen has been reduced couple REDOX reactions & use the released energy to synthesize ATP C 6 H 12 O 6 6O 2 6CO 2 6H 2 O 36ATP +++ oxidation reduction or 38 *Need mitochondria and enzymes to make this happen! Slide 14 Mitochondria: power house Label on your paper Slide 15 2. Citric Acid or Krebs Cycle - occur ONLY if oxygen is present and the cell has mitochondria. - In this stage of cellular respiration, the oxidation of glucose to CO 2 is completed. (this is why we exhale carbon dioxide) It is not necessary to know the individual steps Hans Krebs 1900-1981 Slide 16 Pre Krebs: The pyruvic acid (C 3 ) loses a C to CO 2 and use a H + to form NADH and becomes Acetyl Co-A (C 2 ). Simple put: Pyruvate is converted to Acetly CoA releases 2 CO 2 reduces 2 NAD 2 NADH (moves e - ) produces 2 acetyl CoA Acetyl CoA enters Krebs cycle Slide 17 Citric acid Krebs Cycle Overview Products (per glucose) 2 ATP 6 CO2 8 NADH 2 FADH 2. These energy carriers now enter the electron transport chain (ETC). Aerobic Occurs in the matrix (inner compartment) Slide 18 4C6C4C 2C6C5C4C CO 2 citrate acetyl CoA Count the C & electron carriers! 3C pyruvate reduction of electron carriers This happens twice for each glucose molecule x2x2 CO 2 NADH FADH 2 ATP Slide 19 Oxidative Phosphorylation: process in which ATP is formed as a result of the transfer of electrons from NADH or FADH 2 to O 2 by a series of electron carriers. As opposed to photophosphorylation. ETC 3. Electron Transport System: Slide 20 Does this picture look familiar? You've seen this before in photosynthesis. Animation of the ETCAnimation of the ETC McGraw Hill AnimationMcGraw Hill Animation Products: 34 ATP Slide 21 McGraw Hill Animation Slide 22 NAD dehydrogenase Coenzyme Q Coenzyme c Bc complex Cytochrome c oxidase complex ATP synthase FADH NADH ADP Slide 23 McGraw Hill Animation NAD dehydrogenase Coenzyme Q Coenzyme c Bc complex Cytochrome c oxidase complex ATP synthase FADH NADH H2OH2O ADP Slide 24 McGraw Hill Animation NAD dehydrogenase Coenzyme Q Coenzyme c Bc complex Cytochrome c oxidase complex ATP synthase FADH NADH H2OH2O ADP Slide 25 -net yield of 32 or 34 ATP per glucose molecule - 6 H 2 O are formed when the electrons unite with O 2 * at the end of electron transport chain. * We breath because we need oxygen as the final electron acceptor! The resulting ATP is able to leave the mitochondria by the ATP transport protein in the membrane. It goes to wherever it is needed in the cell. Without oxygen to serve as the final electron acceptor, the process shuts down. Slide 26 Breakdown of One Glucose Molecule Calculations from each: NADH= 2 or 3 ATP can be made FADH 2 = 2 ATP can be made 1. Glycolysis Produces: 2 ATP2 NADH 2. Krebs Cycle (including pre-Kreb s ) - Produces: 2 ATP 8 NADH 2FADH 2 Total:4ATP10 NADH 2 FADH 2 3. ETC - Produces:x 3 x 2 30 ATP 4 ATP = 34 ATP Total: 4ATP + 34 ATP + a grand total of 38 ATP ! Theoretical Yield http://www.youtube.com/watch?v=j7gPtASv0SQ http://www.youtube.com/watch?v=0IJMRsTcwcg For simplicity, however, we look at the theoretical maximum yield of ATP per glucose molecule oxidized by aerobic respiration. Slide 27 Determining the exact yield of ATP for aerobic respiration is difficult for a number of reasons. - bacteria may differ in their carriers in the ETC - the number of ATP generated per reduced NADH or FADH2 is not always a whole number. For every pair of electrons transported to the electron transport chain by a molecule of NADH, between 2 and 3 ATP are generated. For each pair of electrons transferred by FADH2, between 1 and 2 ATP are generated. For simplicity, however, we look at the theoretical maximum yield of ATP per glucose molecule oxidized by aerobic respiration. Slide 28 Slide 29 1 2 6net 5 2 3 2 8NADH Cellular Respiration Summary 4 9 10 2 7net 34 11 - Each NADH produces 3 ATP - Each FADH 2 produces 2 ATP Slide 30 2 NADH 2 ATP net 2 ATP 2 NADH 6 NADH 8 NADH Cellular Respiration Summary 2 FADH 2 6 CO 2 2 ATP net 34 ATP possible - Each NADH produces 3 ATP - Each FADH 2 produces 2 ATP Slide 31 What happens if you dont get enough oxygen? Fermentation: use of pyruvate to make minimal ATP when there is no O 2 = anaerobic By products of fermentation include lactic acid and alcohol Lactic Acid in muscle cells can cause muscle cramps. This happens when the Krebs cycle cannot occur due to lack of oxygen Slide 32 Two Types: 1.Lactic Acid Fermentation: in animals, turns pyruvate into lactic acid 2.Alcoholic Fermentation: in yeast and bacteria, turns pyruvate into ethyl alcohol Slide 33 Lactic Acid Fermentation Alcoholic Fermentation Slide 34 Byproducts of fermentation include lactic acid and alcohol Lactic Acid in muscle cells can cause muscle cramps. This happens when the Krebs cycle cannot occur due to lack of oxygen Slide 35 Fermentation is used in making food products and alcohol products. Applications of fermentation http://www.dnatube.com/video/5784/What-Exactly-is- Fermentation Byproducts of fermentation include lactic acid and alcohol Lactic Acid in muscle cells can cause muscle cramps. This happens when the Krebs cycle cannot occur due to lack of oxygen Slide 36 Oxidative Phosphorylation: (aka ETC of cellular respirations) process in which ATP is formed as a result of the transfer of electrons from NADH or FADH 2 to O 2 by a series of electron carriers. Pre Kreps = Prep Reactions Kreb Cycle= Citric Acid Cycle Why? Substrate Level ATPsynthase= glycolysis and Kreb cycle together Aka/ Other Vocab: GTP: Guanosine-5'-triphosphate- GTP is involved in energy transfer within the cell, a GTP molecule is generated by one of the enzymes in the citric acid cycle. This is leads to the generation of one molecule of ATP, since GTP is readily converted to ATP. Slide 37 Why is it called the citric acid cycle? Slide 38 Is the Mitochondrial Genome Still Functional? Evidence of Endosymbiosis: Mitochondrial genomes are very small and show a great deal of variation as a result of divergent evolution. Mitochondrial genes that have been conserved across evolution include rRNA genes, tRNA genes, and a small number of genes that encode proteins involved in electron transport and ATP synthesis. The mitochondrial genome retains similarity to its prokaryotic ancestor, as does some of the machinery mitochondria use to synthesize proteins. In fact, mitochondrial rRNAs more closely resemble bacterial rRNAs than the eukaryotic rRNAs found in cell cytoplasm. In addition, some of the codons that mitochondria use to specify amino acids differ from the standard eukaryotic codons. Slide 39 Mitochondrial Disease In school, children with mitochondrial disease often seem to work in spurts and then peter out, becoming lethargic and finding it difficult to concentrate. It ranges from intermittent difficulty thinking, remembering, moving and acting, to severe handicaps. Some results may be fatigue, muscle weakness and diabetes. What do you think, at the molecular level, is causing these symptoms? Slide 40 What are the 3 stages of cellular respiration? 1. 2. 3. Slide 41 Food for thought 1. What is the purpose of cellular respiration? 2. Where does cellular respiration occur within the cell? 3. What is the waste product of cellular respiration? Would you go to an oxygen bar? Slide 42 Slide 43 4. Compare Photosynthesis to Respiration a. Where does each occur? b. What are the products of each? c. What compounds are needed to start the processes? d. What is the function of the electron transport chain in each process e. Describe the role of ATPase in both processes. Slide 44 Photosynthesis Respiration Cycle Slide 45 Photophosphorylation vs Oxidative Phosphorylation: Slide 46 Self Test 1. In order to produce energy, cells start with glycolysis. If oxygen is NOT present after glycolysis, what process occurs next? a) Electron Transport Chain b) Krebs Cycle c) Fermentation 2. If oxygen IS present after glycolysis, what process occurs next? a) Electron Transport Chain b) Krebs Cycle c)Fermentation 3. A process that does NOT require oxygen is known as what? a) Aerobic b) Anaerobic 4. In glycolysis, glucose is broken into 2 molecules of __________________ acid 5. Where does the Kreb's cycle occur? _________________ 6. What gas is a waste product produced in the Krebs cycle? ____ Slide 47 7. What enzyme is used in the electron transport chain to create ATP? a. citric acid b. pyruvate c. ATPase 8. Where does glycolyis occur? a. cytoplasm b. mitochondria c. chloroplast 9. Which process produces the largest amount of ATP? a. fermentation b. Krebs Cycle c. ETC 10. The oxygen required by cellular respiration is reduced and becomes part of which molecule? a. ATP b. CO 2 c. H 2 0 Slide 48 The Mystery of the Seven Deaths Case Study: http://sciencecases.lib.buffalo.edu/cs/files/cellular_respiration.pdf http://sciencecases.lib.buffalo.edu/cs/files/cellular_respiration.pdf In this case study, students learn about the function of cellular respiration and the electron transport chain and what happens when that function is impaired. Students play the role of medical examiner as they analyze the autopsy results to determine the cause of the mysterious deaths of these seven victims. Explain the overall purpose of cellular respiration. Describe the intermediate metabolites of cellular respiration. Explain the function and importance of the electron transport chain. Describe the role of oxygen in cellular respiration Slide 49 trophic level: each step in a food chain or food web, feeding level Producer Third level Consumer Secondary Consumers Primary Consumer Slide 50 Tropic levels 10% of the energy at one trophic level is available for organisms at the next trophic level. 90% is used for metabolic activity and is given off as heat. Tropic levels clip 60369