BIOL 240 1st Edition Lecture 10Outline of Last Lecture Overview: Details of MetabolismI. ATP ProductionII. Redox Reactionsa. Oxidationb. ReductionIII. Oxidation of Fuel MoleculesIV. The Stages of Cellular Respiration: A Previewa. Glycolysis: Glucose 2 pyruvatei. Two major phases:b. Pyruvate Oxidation and Citric Acid Cyclei. Pyruvate Oxidation1. Pyruvate Acetyl CoAii. Citric Acid Cycle1. Acetyl CoA Citric Acid Cycleiii. Energyc. Oxidation Phosphorylationi. Electron transport chainii. ChemiosmosisV. Without Oxygena. Other ways to produce ATPVI. Fermentation vs. Respirationa. Similarb. Different VII. Biosynthesis (Anabolic Pathways)Outline of Current Lecture I. HeterotrophsII. AutotrophsIII. Photosynthesisa. Photosynthesis as a redox reactionb. Two stages of PhotosynthesisThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.c. Photosynthetic Pigmentsi. Reaction-center complexIV. Leaf AnatomyV. Chemiosmosis in Chloroplasts and MitochondriaVI. Calvin Cycle vs. Citric Acid CycleVII. Calvin Cyclea. Three phasesVIII. Photorespiration IX. O2/CO2 CompetitionX. Alternative Mechanisms of Carbon Fixationa. C4 Plantb. CAM PlantCurrent LectureI. Heterotrophsa. Have to eat the food for energyII. Autotrophsa. Make food for energyb. Chloroplast to make foodc. Mitochondria to break down food and make ATPd. Plants, alga, unicellular eukaryotes, cyanobacteria, purple sulfur bacteriai. Bacteria: 50% of autotrophsIII. Photosynthesisa. Making of the food for autotrophsb. Energy from the sun organic form of carbonc. 6 CO2 + 12 H2O + Light energy C6H12O6 + 6 O2 + H2Od. Cellular Respiration: C6H12O6 + 6O2 6 CO2 + 6 H2O + energye. Photosynthesis as a redox reactioni. Photosynthesis is an endergonic processii. Opposite from cellular respirationf. Two stages of Photosynthesisi. Light Reaction (light dependent): changing the energy1. The photo part2. Thylakoids3. Makes ATP and NADPH4. H2O O2ii. Calvin Cycle (light independent): synthesizes glucose1. The synthesis part2. Stroma3. Makes ADP and NADP+4. CO2 CH2O (sugar)g. Photosynthetic Pigmentsi. Light travels as waves and particles (photons)ii. Different pigments absorb different wavelengths of lightiii. Non-absorbed wavelengths are reflectediv. Pigments: chlorophyll and carotenoidsv. Electronsvi. Reaction-center complex1. Reaction-center complex surrounded by light-harvesting complex2. Two photosystems: Photosystem I and Photosystem IIa. Photosystem II: 1st photosystem in light reactioni. Pigment molecules accept light at 680nmii. 2 H+ and O gets releasedb. Electron transport chain cytochrome complex (makes ATP)c. Photosystem I: 2nd Photosystem in the light reactioni. Electron comes inii. Pigment molecule accepts light at 700nmd. Electron transport chain NADP+reductase (makes NADPH)3. Absorb different wavelengths of lightIV. Leaf Anatomya. Stomato: CO2 enters and O2 leaves as wasteb. Chloroplasts are found in the mesophyllc. 30-40 chloroplasts per celld. Chloroplastsi. Thylakoids and granaii. StromaV. Chemiosmosis in Chloroplasts and Mitochondriaa. Different sources of energyb. Mitochondria transfer energy from food to ATPc. Chloroplasts transform light energy into the chemical energy of ATPVI. Calvin Cycle vs. Citric Acid Cyclea. Both regenerate starting material after molecules enter and leave the cellb. Citric acid cycle is catabolic (making energy)c. Calvin cycle is anabolic (taking energy)VII. Calvin Cyclea. Carbon enters cycle as CO2 and leaves as glyceraldehyde 3-phosphate (G3P)b. For synthesis of one G3P, the cycle must take place 3 times with 3 molecules of CO2c. Three phasesi. Carbon fixation: CO2 Organic moleculeii. Reduction: Organic molecule + energyiii. Regeneration of the CO2 acceptord. 9 ATP + 6 NADPHVIII. Photorespiration a. Rubisco is very inefficienti. Major protein of most photosynthetic cellsb. Can bind to O2 instead of CO2c. Photorespiration decreases organic outputi. Consuming ATP and O2ii. No production of ATP or sugarIX. O2/CO2 Competitiona. Rubisco evolved when O2 levels were non-existentb. Now CO2 and O2 competei. Direction of reaction is determined by concentrationc. Global warming and rise of CO2 10% increase in crop yield i. 270 ppm in 1870 to > 400 ppm nowX. Alternative Mechanisms of Carbon Fixationa. Adaptation to dehydration is a problem for land plantsb. On hot, dry days, plants close stromata, which conserves H2Oc. Reduces access to CO2 and causes O2 to build upd. C4 Planti. A different enzyme reacts with CO2 in mesophyll cell1. Where O2 is highii. Exported to bundle-sheath cells, where CO2 is released1. Where CO2 is high because it is just released2. CO2 is then used in the Calvin Cyclee. CAM Planti. Open their stomata at night1. CO2 into acidii. Close their stomata during the day1. CO2 is released and used in the Calvin
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