Presentation on theme: "Chapter 9: Cellular Respiration"— Presentation transcript:
1Chapter 9: Cellular Respiration 9-1 Chemical Pathways
2Chemical Energy and Food Cellular respiration happens slowly and in many steps.If all the energy was release in one step Most would be lost as light and heat!Cellular respiration breaks down glucose molecules and banks their energy in ATP
3Chemical Energy and Food PHOTOSYNTHESIS___________ + _________ + ___________ →_______________ + __________6 CO26 H2OC6H12O66O2CELLULAR RESPIRATIONC6H12O66 CO2_____________ + _________ →________ + __________ + __________6O26 H2OThe two equations are exact opposites!
4Chemical Energy and Food Amount of heat it takes to raise 1 gram of water 1o Celsius = calorieUnit for measuring energy in food = Calorie1 Calorie = 1,000 calories
5Overview of Cellular Respiration Occurs in three main stagesStage 1: GlycolysisOccurs in the cytoplasmBreaks down glucose into pyruvate, producing a small amount of ATPStage 2: The citric acid cycle (Krebs cycle)Takes place in the mitochondriaCompletes breakdown of glucose, produces a small amount of ATPProvides third stage of cell respiration with electronsStage 1Stage 2Stage 3
6Overview of Cellular Respiration Stage 3: Oxidative phosphorylation (ETC)Occurs in the mitochondriaUses the energy released by “falling” electrons to pump H+ across a membraneHarnesses the energy of the H+ gradient through chemiosmosis, producing ATPStage 3
7Understanding Oxidation and Reduction Oxidation is the loss of electrons; electrons are removed from hydrogen atoms contained in glucose.Reduction is the gain of electrons; oxygen atoms accept hydrogen and electrons forming water H2O.Remember OIL RIG (oxidation is loss, reduction is gain)
8Electron Carriers (enzymes) Involved NAD+ (Nicotinamide adenine dinucleotide)Accepts H+ to become NADHFAD (Flavin adenine dinucleotide)Accepts 2H+ to become FADH2
9Overview of Cellular Respiration NADHFADH2GLYCOLYSISGlucosePyruvateCITRIC ACID CYCLEOXIDATIVE PHOSPHORYLATION (Electron Transport and Chemiosmosis)Substrate-level phosphorylationOxidative phosphorylationMitochondrionandHigh-energy electrons carried by NADHATPCO2CytoplasmStage 1Stage 3Stage 2Krebs
10(Glykos = sweet, Lysis = split apart) 9.2 Glycolysis(Glykos = sweet, Lysis = split apart)The first step in cellular respiration = GlycolysisHappens in the CYTOPLASM outside the mitochondriaDoes not require oxygen, BUT it needs some energy to get it started.What molecule is going to supply the energy?ATP
11____________________ + _______________ Glycolysis________↓___________ → → _________________________________ + _______________GLUCOSE2 PYRUVIC ACIDATP ATP ATP ATPNADH NADHPUT IN 2 ATP and GET BACK 4 ATPNet gain of 2 ATP and 2 NADH
12Glycolysis Produces pyruvic acid (pyruvate – a 3 carbon compound) Cell needs to invest some energy to get a higher return (2 ATP gained)Occurs quickly, in miliseconds to respond to increased energy demand
14Mitochondria Structure Has a double membrane, with an intermembrane space between the two layers.Cristae are folds of the inner membraneThe matrix is the innermost compartment, which is filled with a gel-like fluid.Krebs Cycle occurs in the matrix of the mitochondria.
15The Krebs Cycle Pyruvic acid enters the mitochondria matrix Pyruvic acid is converted into an intermediate 2 carbon molecule called Acetyl-CoA before entering the Krebs Cycle.The Krebs cycle breaks down carbon compounds into carbon dioxide (waste), ATP, NADH, and FADH2
16The Krebs CycleThe Krebs Cycle Produces(in one turn)____3114
17The Krebs Cycle Carbon dioxide is lost to the atmosphere as waste ATP can be used directly to supply energy for the cellHigh energy electron carriers move into the ELECTRON TRANSPORT CHAIN
18Electron Transport Chain Electrons from NADH and FADH2 travel down the electron transport chain, between protein complexes to oxygen (final electron acceptor), which picks up H+ to form waterEnergy released by the redox reactions is used to pump H+ into the space between the mitochondrial membranesVirtual Cell ETC AnimationH2ONAD+NADHATPH+Controlled release of energy for synthesis of ATPElectron transport chain2O22e+1
19ChemiosmosisIn chemiosmosis, the H+ diffuses back through the inner membrane through ATP synthase complexes. Driving the synthesis of ATPIntermembrane spaceInner mitochondrial membraneMitochondrial matrixProtein complexElectron flowElectron carrierNADHNAD+FADH2FADH2OATPADPATP synthaseH++PO2Electron Transport ChainChemiosmosis.OXIDATIVE PHOSPHORYLATION+ 212
21Fermentation Pyruvic acid moves to the next step If there is no oxygen = anaerobicIf there is oxygen = aerobic
22FermentationFermentation – process by which cells release energy in the absence of oxygenTwo types of fermentation:Alcoholic FermentationLactic Acid Fermentation
23Alcoholic Fermentation _______ +_____ →__________ + ______ + _____PYRUVIC ACIDALCOHOLCO2NAD+Happens when yeast makes bread dough rise, CO2 bubbles make air spaces in bread.(Alcohol evaporates during cooking)Happens when:Yeast make beer and wine
24Lactic Acid Fermentation _______ +_____ →______________ + ________PYRUVIC ACIDLACTIC ACIDNAD+Happens in muscles during exercise when body can’t get oxygen to tissues fast enough.Lactic acid builds up in muscles causing soreness.Bacteria use lactic acid fermentation to make:yogurt, cheese, sour cream, pickles, sauerkraut, kimchi
26The Totals Cellular Respiration (aerobic: with oxygen) 1 glucose → 36 ATPFermentation (anaerobic: without oxygen)1 glucose → 2 ATP
27Respiration Questions List the reactants and products of respiration2. List the three steps (stages) involved in respiration3. Name two electron carriers involved4. What step produces the most ATP
28Respiration Questions In your group:5. See if you can write the chemical equation for respiration (inputs and outputs)6. What is the organelle in cells that is “releasing” energy during respiration?7. What primary molecule is energy being “released” from?8. How is the sun indirectly involved in respiration?
29Fermentation Questions List two types of fermentationList the reactants for both types of fermentationList the products for fermentation used to brew beerList the products for fermentation used to make yogurtWhat important molecule cycles back from fermentation to keep glycolysis going?What process starts fermentation?