Cellular Respiration Overview Lecture 1 ___________ use energy from sunlight or chemicals to make their own food AUTOTROPHSIn the last chapter green plants used ________________ trap energy from __________ and make ______________ sunlight food (glucose) PHOTOSYNTHESIS We get our energy from the __________ plants made during _______________ when we eat plants or eat animals that ate the plants. GLUCOSE In this chapter we will learn how ______________ get their energy by consuming other organisms. Image from:HETEROTROPHSPHOTOSYNTHESIS In this chapter, we will learn how this glucose is ____________ by organisms and the _______ is stored as _______ What kind of organisms do this? energy broken down ATP Animals (Including humans) ALL LIVING THINGS NEED ENERGY! All organisms burn glucose for fuel fungi bacteria plants PHOTOSYNTHESIS ___________ + _________ + ___________ _______________ + __________ 6 CO 2 6 H 2 OC 6 H 12 O 6 6O 2 _____________ + _________ ________ + __________ + __________ ______________________________________________________________ CELLULAR RESPIRATION C 6 H 12 O 6 6O 2 6 CO 2 6 H 2 O The two equations are exact opposites! CELLULAR RESPIRATION happens __________ in ________________. If all the energy was released in one step most would be lost as ____________________!slowly many steps light and heat See why cells use cellular respiration Prevents energy release in 1 explosive step Allows energy to be released slowly in steps and captured as ATP Electron route: food NADH ETC oxygen Similar to photosynthesis ETC, just different electron acceptor ELECTRON TRANSPORT CHAIN MITOCHONDRIA = cell power plant Surrounded by ___________ membrane Outer membrane & Inner membrane (called _______________ ) Space between inner membrane & outer membrane = ____________________ Space inside cristae folds = _________________ INTERMEMBRANE SPACE DOUBLE MATRIX CRISTAE FAD FADH 2 NAD + NADH HIGH ENERGY ELECTRON CARRIERS Steps of Cellular Respiration Lecture 2 See glycolysis movie The first step in cellular respiration = _______________ happens in the ________________ outside the mitochondria occurs _________________________ GLYCOLYSIS CYTOPLASM with or without oxygen Glycolysis (GLYKOS = ________ LYSIS= ___________ ) Requires ____________to get it started. Split apartsweet ENERGY Evolutionary Significance Most widespread metabolic pathway suggests ancient prokaryotes probably used glycolysis to make ATP before oxygen was present Earliest fossil bacteria present 3.5 billion years ago but large amounts of oxygen not present until 2.7 billion years ago Glycolysis happens in cytoplasm without membrane bound organelles suggests it was found in early prokaryotic cells since eukaryotes appeared 1 billion years after prokaryotes (Endosymbiotic theory) MITOCHONDRION = using energy from breaking a chemical bond to add a P directly from a phosphorylated molecule to ADP without a proton gradient SUBSTRATE LEVEL PHOSPHORYLATION PYRUVIC ACID MOVES TO NEXT STEP IF THERE IS NO OXYGEN (______________) IF THERE IS OXYGEN (_____________) = ANAEROBIC = AEROBIC Cellular respiration Glycolysis: cytosol; glucose pyruvate Krebs Cycle: mitochondrial matrix; pyruvate CO 2 NADH made Electron Transport Chain: cristae; NADH & FADH 2 donate electrons oxygen Pyruvate is transported into mitochondrion and Acetyl CoA produced For each pyruvate converted into acetyl CoA 1 molecule of CO 2 is released; NAD+ ---> NADH; Coenzyme A (from B vitamin) Krebs Cycle AnimationKrebs Cycle Animation- Krebs Cycle = Citric Acid Cycle OAA CITRIC ACID Krebs Cycle Animation Krebs Cycle Oxaloacetate (OAA) combines with 2 Cs from Acetyl CoA to make Citric acid CoA recycles 2 C atoms from pyruvate exit as CO 2 For each pyruvate that enters: 2 CO 2 released 3 NAD + reduced to 3 NADH; 1 FAD + reduced to 1 FADH 2 (riboflavin, B vitamin); 1 ATP molecule Electron transport chain More on Making ATP 3 places in the chain make ATP NADH FADH 2 Electrons from NADH start higher in the waterfall, so they generate more ATP than FADH 2 electrons, which start lower in the waterfall and miss one ATP-generating step. Electron transport chain ETC includes Cytochromes Ubiquinone (Q) NADH & FADH 2 pass electrons pass down ETC Energy from moving electrons concentrates H + ions in __________________ ________________: harnesses the flow of H + back into the matrix make ATP (oxidative phosphorylation) ________ is final electron acceptor ________ intermembrane space ATP synthase Oxygen H2OH2O Cellular Respiration Grand Total Glycolysis: 2 ATP (substrate-level phosphorylation) Krebs Cycle: 2 ATP (substrate-level phosphorylation) Electron transport & oxidative phosphorylation: 2 NADH (glycolysis) 6ATP 2 NADH (acetyl CoA) 6ATP 6 NADH (Krebs) 18 ATP 2 FADH 2 (Krebs) 4 ATP 38 TOTAL ATP from 1 molecule of glucose (-2 ATP to transport 2 pyruvate into mitochondria) NET of 36 ATP CHEMIOSMOSIS= Generation of ATP from a proton gradient. It occurs in all living things Chloroplasts do it to make ATP in light reactions Mitochondria do it to make ATP following ETC Prokaryotes create gradient across cell membrane to make ATP to pump nutrients & waste and move flagella PHOTOPHOSPHORYLATION = Using hydrogen gradient generated by thylakoid membrane during the light reactions of photosynthesis to make ATP CHLOROPLAST MITOCHONDRION = using proton gradient created by electron transport chain in cristae membrane to make ATP OXIDATIVE PHOSPHORYLATION In cellular respiration, decoupling oxidative phosphorylation from electron transport is involved in thermoregulation ADD MORE DETAILS Fermentation WHAT IF THERE IS NO OXYGEN? IF THERE IS NO OXYGEN (______________) IF THERE IS OXYGEN (_____________) = ANAEROBIC = AEROBIC Related metabolic processes Fermentation: alcohol~ pyruvate ethanol lactic acid~ pyruvate lactate _______ + _____ __________ + ______ + _____ ALCOHOLIC FERMENTATION PYRUVIC ACID ALCOHOL Happens when yeast makes bread dough rise CO 2 bubbles make air spaces in bread Alcohol evaporates during cooking CO 2 NAD + _______ + _____ __________ + ______ + _____ ALCOHOLIC FERMENTATION PYRUVIC ACID ALCOHOL Used to make alcoholic beverages CO 2 NAD + _______ + _____ ______________ + ________ LACTIC ACID FERMENTATION PYRUVIC ACID LACTIC ACID Happens in muscles during exercise when body cant get oxygen to tissues fast enough. Lactic acid builds up in muscles causing soreness NAD + _______ + _____ ______________ + ________ LACTIC ACID FERMENTATION PYRUVIC ACID LACTIC ACID Happens when bacteria are used to make foods and beverages like yogurt, cheese, buttermilk, sauerkraut, kimchi NAD + WITHOUT OXYGEN, PYRUVIC ACID ___________ and all the _______ carriers get full. Eventually glycolysis will WHY DO FERMENTATION? WHY NOT JUST KEEP MAKING ATP USING GLYCOLYSIS? builds up NAD + _______ + _____ __________ + ______ + _____ FERMENTATION HAPPENS so cells can ____________________ needed to keep glycolysis going PYRUVIC ACID ALCOHOL CO 2 NAD + REGENERATE the NAD + LACTIC ACID NAD + You get the NAD + carriers back ______ __________________________ = organisms that can make ATP using either fermentation or cellular respiration Ex: yeast and many bacteria With oxygen pyruvate Krebs cycle Without oxygen fermentation FACULTATIVE ANAEROBES Organisms can use a variety of molecules for fuel __________________= breakdown of fatty acids into 2 carbon fragments that enter Krebs cycle as acetyl CoA 1 g of fat twice as much ATP as 1 g of carbohydrate Beta oxidation=