BIOL 1441 1st Edition Lecture 17 Outline of Last Lecture I Substrate level phosphorylation II Glycolysis III Citric acid cycle IV Electron transport chain V Cellular Respiration VI Chemiosmosis VII ATP synthase multisubunit complex Outline of Current Lecture I Hydrogen gradient II ATP production III Fermentation IV Fermentation vs cellular respiration V Facultative anaerobes VI Versatility of catabolism VII Photosynthesis VIII Plant anatomy IX Redox reaction X Respiration vs photosynthesis These 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 XI Sunlight Current Lecture I II III H Gradient a Energy sources i Electrons ii The gradient itself b ETC uses exergonic flow of electrons to pump H across the membrane i Low H in matrix basic environment high pH ii High H in inner membrane space acidic environment low pH c How are H being moved i They are actively being pumped to intermembrane space ii Then they diffuse into the matrix 1 ATP MADE IN THE MATRIX iii Energy release e moves from less electronegative to more electronegative molecule iv Proton motive force force drives H back across the membrane through ATP synthase channels 1 DIFFUSION ATP Production a 32 34 ATP not exact number i DURING OXIDATIVE PHOSPHORYLATION b FADH2 transports enough H for 1 5 2 ATP i FADH2 COMES IN AT A LOWER ENERGY LEVEL c TOTAL ATP PRODUCTION 36 38 ATP 2 MORE FROM SUBSTRATE PHOSPHORYLATION Fermentation no oxygen a Glycolysis can produce ATP without O2 SAME IN AEROBIC RESPIRATION i Anaerobic respiration b Fermentation generates ATP by substrate level phosphorylation glycolysis i Problem needs sufficient supply of NAD to accept electrons during glycolysis 1 Mechanism is needed to recycle NAD to NADH no ETC ii Solution transfer electrons to pyruvate 1 GIVES ELECTRONS TO PYRUVATE TO REGENERATE NAD c Fermentation reactions that regenerate NAD which can be reused by glycolysis i ATP produced from glycolysis only d Fermentation pyruvate reduction e PURPOSE OF FERMENTATION OXIDIZE NADH INTO NAD TO KEEP GLYCOLYSIS GOING FORWARD f FERMENTATION IS INEFFICIENT BECAUSE MOST OF THE ENERGY IS IN PYRUVATE AND THEY DON T USE PYRUVATE IV V VI g Different Types i Alcohol fermentation 1 Releases a CO2 2 Convers pyruvate into acetaldehyde a NADH GIVES ELECTRONS TO ACETALDEHYDE 3 Acetaldehyde is REDUCED into ETOH ethanol 4 OXIDIZING AGENT ACETALDEHYDE 5 REDUCING AGENT NADH ii Lactic acid fermentation 1 Pyruvate is reduced by NADH forming lactate as an end product with no release of CO2 2 Lactic acid fermentation by some fungi and bacteria is used to make cheese and yogurt 3 Human muscle cells use lactic acid fermentation to generate ATP when O2 is scarce a When at peak exertion enzymes cant keep up with cycle formation of lactic acid 4 STEPS a NADH gives electrons directly to pyruvate Pyruvate is reduced to lactic acid Fermentation vs Cellular Respiration a Both use glycolysis to oxidize glucose to pyruvate b Both use NAD as an oxidizing agent it oxidizes glucose c Difference mechanism for oxidizing NADH back to NAD i Different final electron acceptors pyruvate or acetaldehyde in fermentation and O2 in cellular Rs d Cellular Rs much more efficient produces more ATP releases stored energy in pyruvate i Cellular Rs 36 38 ATP ii Fermentation 2 ATP Facultative Anaerobes a Use either fermentation or cellular Rs i CAN DO BOTH SURVIVE ON BOTH b Yeast many bacteria are facultative anaerobes c PROKARYOTES USE PLASMA MEMBRANE Versatility of Catabolism a Catabolic pathways funnel electrons from many kinds of organic molecules into cellular Rs b Don t usually obtain calories in form of glucose i Fats proteins sucrose starch ii Proteins are NOT a good source of energy not a lot of hydrogen 1 Broken down into amino acids VII VIII IX 2 Amino groups must be removed deamination ammonia ureaexcreted in urine 3 Amino acids can be turned into pyruvate glycolysis acetyl CoA and citric acid cycle iii Fats good source of energy 1 Glycerol is converted to glyceraldehyde 3 phosphate glycolysis 2 Fatty acids are broke down by beta oxidation enter into citric acid cycle as acetyl CoA Photosynthesis Ps Converts solar energy into chemical energy food sugar a Anabolic rxn building organic molecules i Needs Sunlight CO2 H2O b Directly or indirectly Ps nourishes almost the entire living world c Autotroph self feeders i Produce their own organic molecules from inorganic materials d Heterotroph other feeder i Unable to make their own food consumers humans e Photoautotrophs i Most plants photoautotrophs use energy of sunlight to make organic molecules from water CO2 ii Only materials they require water CO2 minerals from soil iii Ps occurs in algae protists prokaryotes f Two Stages of Photo synthesis i Light rxns photo part converts solar energy to chemical energy 1 Occur in thylakoids 2 Split water release O2 produce ATP form NADPH 3 Light energy initially converted into chemical energy in form of NADPH ATP ii Calvin cycle synthesis part synthesizes sugar 1 Occurs in stroma 2 Forms sugar from CO2 using ATP NADPH from light rxn 3 Sugar is produced in Calvin cycle a Can only do so with NADPH and ATP produced in light rxn 4 Dark rxn s do not require light directly Plant Anatomy a Chloroplasts where photosynthesis happens b Located in all green parts of plant leaves stem unripened fruit c Leaves major locations of Ps i million chloroplasts per sq millimeter of leaf surface d Green color is from chlorophyll green pigment within chloroplasts e Chloroplasts i Light energy absorbed by chlorophyll drives synthesis of organic molecules in chloroplast X XI XII ii Chloroplasts found mainly in cells of the mesophyll tissue in the interior of the leaf iii Stroma a dense fluid do not confuse with stomata iv Thylakoids interconnected membrane sacs 1 CHLOROPHYLL LOCATED IN THE THYLAKOID MEMBRANES f Stomata i CO2 enters O2 exits leaf through microscopic pores stomata ii Water absorbed by roots delivered to leaves in veins 1 Roots breath Absorb O2 iii Veins export sugar to roots Photosynthesis Redox Reactions a Chloroplasts split water into hydrogen oxygen b Incorporate electrons of hydrogen into sugar molecules put hydrogen electrons on CO2 i Hydrogen is oxidized loses electrons ii CO2 molecule is reduced gains electrons iii Oxygen from water releases as molecular O O2 1 Oxygen we breath Respiration vs Photosynthesis a Rs energy released from sugar oxidize glucose i Electrons