BIOL 1411 1st Edition Lecture 12 Outline of Last Lecture I. Enzymatic inhibitionII. BioenergeticsOutline of Current Lecture I. Bioenergeticsa. Pyruvate Oxidationb. Citric Acid Cyclec. Oxidative Phosphorylationd. ChemiosmosisII. Fermentationa. Lactic Acidb. Alcohol fermentationLecture- Glycolysis Step 6: redox reaction- Pyruvate Oxidation (also called decarboxylation)o Links glycolysis (in cytoplasm) and the citric acid cycle (in mitochondria)o Occurs in the liquid mitochondrial matrix- Pyruvate (3C)  acetate (C2) + CO2o CO2 released as wasteo NAD+ is reduced to NADH, capturing energyo Some energy is stored by combining acetate and Coenzyme A to for acetyl CoA- Citric Acid Cycle (Krebs)o Eight reactions that begin with acetyl CoAo In a steady state – the concentrations of the intermediates don’t changeo Inputs: acetyl CoA, electron carriers NAD+ and FAD and GDP Energy released is captured by the electron carriers and GDPo Outputs: CO2, reduced electron carriers (NADH, FADH2) and GTP (which convertsADP to ATP)o Strip energy off of citrate o Whenever there is a decrease in C#, CO2 is released- Summary to this pointo Glucose  2 pyruvate  6 CO2o 4 ATP madeThese 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.o 10 NADH, 2 FADH2 – holds energy in the electronso re-oxidation is going to be linked to “lots” more ATP = oxidative phosphorylation- Oxidative Phosphorylation: involves proteins and elctron carrier molecules imbedded in the mitochondrial inner membrane (cristae)o 2 interconnected stages Electron transport chain- e- from NADH and FADH2 pass through a respiratory chain of inner membrane carriers- 4 protein complexes (I,II,III,IV), Ubiquinone (Q), Cytochrome c- Oxygen is the final electron acceptor- ETC makes no ATP directlyo Chemiosmosis Protons (H+) diffuse back into the mitochondria through ATP synthase, a channel protein Diffusion is coupled to ATP synthesis Energy is used to transport protons against their concentration gradient- Protons accumulate in the inter-membrane space- Creates charge difference across membrane- potential energy This Proton-motive force later drives protons back across membrane- The protons move through the ATP synthase channel, providing energy to phosphorylate ADP- ATP synthesis is favored over ATP hydrolysiso ATP leaves the mitochondria once made, keeping the concentration low- ATP synthase: a molecular machineo H+ flows rom inter-membrane space through synthase to matrixo Flow rotates rotor, driving conformation changes in catalytic knob subunitso Shape changes force condensation of ADP + Pi  ATPo Proton gradient!- ATP Generation in absence of oxygen- Fermentationo Lactic acido Ethanol- Anaerobic respiration- respiratory chains that have a different final e- acceptor (nitrate, sulfate, sulfur, metal ions) - Lactic Acido Occurs in microorganisms, some muscle cellso Pyruvate is the electron acceptor- becomes reducedo Oxidizes NADH back to NAD+ so more glycolysis can occuro Lactate is the product and can build upo No additional ATP is made- Alcohol fermentationo Yeasts and some plant cellso Requires 2 enzymes to metabolize pyruvate to ethanolo CO2 is a waste producto The intermediate, acetaldehyde is reduced by NADH + H+, producing NAD+ and glycolysis continues- Cellular respiration yields more energy than fermentationo Neither aerobic respiration or fermentation capture all of the energy released by glucose oxidationo 32 ATP for cellular respirationo Only get 2 ATP for fermentation o AR is 41% efficient, rest lost to heat- Metabolic pathways interrelated and regulatedo An interexchange of molecules occurs between metabolic pathwayso Pathways are interrelated by shared substances - Catabolism and anabolism are integratedo Negative and positive feedback controlso Allosteric inhibitors act on key enzymes- Concentrations of biochemical molecules remain constant (glucose concentration in blood) - *Reoccurring themes of living