CELLULAR RESPIRATION IICELLULAR RESPIRATIONCELLULAR RESPIRATION BEGINS IN THE CYTOPLASMTHE GLYCOLYTIC PATHWAYSlide 5SUMMARY OF GLYCOLYSISSlide 7TWO PATHWAYS FOLLOWING GYLCOLYSISFERMENTATIONTWO PATHWAYS AFTER GLYCOLYSISAEROBIC RESPIRATION OCCURS IN MITOCHONDRIATHE TRANSITION REACTIONSSlide 13Slide 14OVERVIEW SO FAR…SUMMARY OF AEROBIC RESPIRATIONSUMMARY OF AEROBIC RESPIRATION SO FAR…..ELECTRON TRANSPORT CHAINELECTRON TRANSPORT CHAINSlide 20ELECTRON TRANSPORT CHAINSlide 22Slide 23Slide 24Slide 25Slide 26CONCLUSIONS: CELLULAR RESPIRATIONSlide 28CELLULAR RESPIRATION IIHow Cells Obtain Energy to Sustain LifeCELLULAR RESPIRATIONThree Major Phases:1. Glycolysis2. Krebs Cycle 3. Electron Transport ChainCELLULAR RESPIRATION BEGINS IN THE CYTOPLASM Glucose Metabolism (first part of respiration):–Starts in cytoplasm of cells of all organisms»Aerobic & Anaerobic–Glycolosis »Lysis = break down»Glyco = prefix for sugarTHE GLYCOLYTIC PATHWAYEnergy Input: ATPTHE GLYCOLYTIC PATHWAYEnd product: 2 pyruvate molecules(Energy Output) ATP Reduced Helper NADHSUMMARY OF GLYCOLYSIS•Glycolysis:–One Glucose molecule (6 C) is transformed into two (3 C) organic molecules called “pyruvate”SUMMARY OF GLYCOLYSISAdditionally, the Enzyme Mediated Reactions of Glycolysis Yield:–ATP molecules –Reduced Helper (NADH)(NAD+ + H & 2e-  NADH)***NOTE: NADH is a high energy e- carrier that will become important later!***TWO PATHWAYS FOLLOWING GYLCOLYSIS•In Absence of Oxygen:•Anaerobic Respiration•In Presence of Oxygen:•Aerobic RespirationFERMENTATION In Absence of Oxygen: • Energy production occurs through Fermentation•Occurs in cytoplasm•Only yields 2 ATP per glucose but occurs fastTWO PATHWAYS AFTER GLYCOLYSISIn Presenc e of Oxygen:•Aerobic RespirationAEROBIC RESPIRATION OCCURS IN MITOCHONDRIATransition Reactions:–Mitochondrial membraneKrebs Cycle:–Mitochondrial matrixElectron Transport Chain:–Inner membrane of mitochondriaTHE TRANSITION REACTIONSTransition Reaction:•Pyruvate converted into Acetyl-CoA•Reduced helper (NADH) produced•CO2 producedKREBS CYCLE•We Continue a Series of Redox Reactions During Krebs CycleSUMMARY OF KREB’S CYCLEKreb’s Cycle:•2 acetyl Co A produce:• Reduced helpers• ATP • CO2OVERVIEW SO FAR…During Glycolysis, Transition Reactions & Krebs:–Organic molecules are oxidized–Eventually all C in glucose is found in CO2–Helper Molecules Reduced–NAD+  NADH–FAD  FADH2–Very little ATP producedSUMMARY OF AEROBIC RESPIRATIONSUMMARY OF AEROBIC RESPIRATION SO FAR…..ELECTRON TRANSPORT CHAIN•In the last phase of cellular respiration, electrons are donated to proteins in the mitochondrial inner membraneELECTRON TRANSPORT CHAIN•ETC occurs at mitochondrial inner membrane•Helper molecules donate e-s to proteins embedded in membranee-ETC: • Series of Redox Reactions where: • Proteins pass e-s down chain•Ea. protein is more electronegative than preceding• Oxygen is final e- acceptor•Water forms when Oxygen combines with electrons & 2 H+ ELECTRON TRANSPORT CHAINe-ELECTRON TRANSPORT CHAINSome Proteins:•Carry electrons (only) •Carry electrons while pumping protons: H+–H+ pumped from matrix  inter- membrane space–Creates electrochem. gradientELECTRON TRANSPORT CHAINElectrochemical Gradient:•Source of power for ATP synthesis!High H+Low H+ELECTRON TRANSPORT CHAINATP SYNTHESIS:•ATP synthesis is coupled to diffusion of H+ through ATP SynthaseELECTRON TRANSPORT CHAINATP Synthesis:•H+ returns to matrix (moving down its gradient)•ATP synthase attaches inorganic phosphate to ADP •“Oxidative Phosphorylation”•ATP produced!ELECTRON TRANSPORT CHAINCELLULAR RESPIRATION•Most ATP is Synthesized During the ETCCONCLUSIONS: CELLULAR RESPIRATIONCellular (aerobic) Respiration:–Involves series of redox reactions that release energy for ATP synthesis–Begins with breakdown of sugar and ends with ATP synthesis through ATP Synthase–By products include: »H2O & CO2In absence of carbs, other molecules can be used to produce chemical energy:•Proteins•FatsMETABOLISM OF MACROMOLECULES IS TIED TO CELLULAR