5Question… Why do we breathe? 4th grade answer: “so we don’t die” 7th grade answer: “to take in oxygen, and breathe out carbon dioxide”10th grade answer: TO FUEL CELL RESPIRATION!
6Basic ideasBreaking down high energy, large molecules into lower energy, smaller molecules.If this process stops, cells DIE!!!!Requires oxygen to fully occur.Three step process;Step 1 occurs in the cytoplasm of the cellSteps 2 & 3 occur in the mitochondria of the cell
8This is the equation!C6H12O6 +6O2 -> 6CO2 + 6H2O + energy (ATP& heat)How does this look familiar?Where do the “ingredients” (reactants) come from?What happens to each of the “leftovers” (products)
9WHAT’S ATP GOT TO DO WITH IT? Adenosine TriphosphateChemical energy source for the cellThink of it as cellular “money”
10Three Stages of Cellular Respiration STEP 1: Glycolysis (“GLUCOSE SPLITTING”)1st stage of ALL energy releasing pathways.Occurs in cytoplasmA couple of ATP “coins” madeIf you’re fermenting, stop here!STEP 2: Krebs Cycle (citric acid cycle)Occurs in the mitochondriaA few more ATP “coins” madeSTEP 3: Electron Transport Chain (phosphorylation)Occurs in the mitochondria (membranes)ATP JACKPOT!!!!!!!!!!!!!!
11CELL RESPIRATION OVERVIEW Convert glucose to ATPAccomplished in 3 steps:Glycolysisin cytoplasmKrebs Cyclein mitochondriaElectron Transport Chainin mitochondriaRemember: this requires Oxygen
12GlycolysisFood must have been transported to cells via the bloodstreamdigested food gets into the bloodstream by diffusing through the intestinal walls into the capillaries.1st stage in energy release from foodInput = glucose,Outputs = small amount of ATP and pyruvatesThese outputs are the inputs for the next stage
13Krebs Cycle Series of chemical reactions ATP (energy) released CO2 (waste) released
14Electron Transport Chain Series of reactionsReleases LOTS more ATP
15CASHING IN…Total energy released from 1 GLUCOSE MOLECULE DURING CELL RESPIRATION:38 ATP
16CELL RESPIRATION OVERVIEW Convert glucose to ATPAccomplished in 3 steps:Glycolysisin cytoplasmKrebs Cyclein mitochondriaElectron Transport Chainin mitochondriaRemember: this requires Oxygen
17UH, OH…PROBLEM 1.) What if you don’t have mitochondria? 2.) What if there isn’t much oxygen around?
18FERMENTATION TO THE RESCUE! 2 KINDS:AlcoholicLactic AcidThese are ANAEROBIC processesLittle to no oxygen required
19BIG PICTURE: When are these used? CELL RESPIRATIONEukaryotes with mitochondriaAdequate oxygenEx.AnimalsPlantsPRODUCES LOTS OF ATP!FERMENTATIONProkaryotes (no mitochondria) AND/ORInadequate or no oxygen availableEx.YeastBacteriaOverworked Human muscles (no, your brain is not a muscle!)Produces very little ATP, but hey, some is better than none!