logging in or signing up cellular respiration unitbiokmns Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: Embed: Flash iPad Dynamic Copy Does not support media & animations Automatically changes to Flash or non-Flash embed WordPress Embed Customize Embed URL: Copy Thumbnail: Copy The presentation is successfully added In Your Favorites. Views: 487 Category: Education License: All Rights Reserved Like it (0) Dislike it (0) Added: September 12, 2012 This Presentation is Public Favorites: 0 Presentation Description No description available. Comments Posting comment... Premium member Presentation Transcript Respiration: Respiration Respiration is a metabolic process of breaking complex macromolecule (catabolism) to simple carbon compound (CO 2 , lactate, ethanol) that occurs in cells to yield ATPPowerPoint Presentation: How would this possibly happened?PowerPoint Presentation: Ability to do work . Essential for the 7 characteristics of life: M ovement R eproduction G rowth R espiration E xcitability E xcretion N utrition EnergyPowerPoint Presentation: How do living organisms get energy? Food (e.g:carbohydrate) Digestion (enzyme) Glucose Cellular respiration begins energyProduction of Energy: Production of Energy http://www.google.com.my/imgres?q=production+of+energy,+cellular+respiration+and+photosynthesis&start=196&hl=en&gbv=2&biw=1280&bih=587&tbm=isch&tbnid=zJjNfHrlQAc6BM:&imgrefurl=http://studio17.com.ua/wp-content/uploads/2012/cellular-respiration-cycle-diagram&docid=PjIlwv176b4ONM&imgurl=http://studio17.com.ua/wp-content/uploads/2012/cellular-respiration-cycle-diagram-PowerPoint Presentation: Role of Respiration To produce ATP, (energy currency of the cell)What is ATP: What is ATP Adenosine triphosphate. Comprises of an adenosine molecule bonded to 3 phosphate groups. Each phosphate bond contains energy especially the bond between the second and third phosphate. The unstable bonds can be hydrolyzed in an exergonic reaction that releases energy. ATP + H 2 O ADP + H 2 OThe bond that stores very high energy: The bond that stores very high energy ATP build by: # Nucleotide with unstable phoshate bonds that the cell hydrolyzes for energy to drive endergonic reactions. -Adenine, a nitrogenous base -Ribose, five carbon sugar -Chain of three phosphate group STRUCTURE OF ATP http://www.google.com.my/imgres?q=structure+of+atp&num=10&hl=en&gbv=2&biw=1280&bih=587&tbm=isch&tbnid=QnIjLzVx4aa0iM:&imgrefurlPowerPoint Presentation: ATP cycle http://www.google.com.my/imgres?q=atp+cycle&num=10&hl=en&gbv=2&biw=1280&bih=587&tbm=isch&tbnid=_v74UFRjvDnv9M:&imgrefurl This energy is used by cell to do workRespiration: Respiration Categories of RespirationPowerPoint Presentation: RESPIRATION CELLULAR RESPIRATION EXTERNAL RESPIRATION Involves the exchange of oxygen & carbon dioxide at the respiratory surface Internal/cell/tissue respiration. a sequence of enzyme controlled biochemical reactions. Aerobic respiration : if oxygen is used Anaerobic respiration : if oxygen is not requiredTypes of Respiration: A metabolic process that does not require O 2 in the breakdown of glucose. 2 types: Alcohol fermentation (plant) Lactate fermentation / Muscle respiration (animal) Anaerobic respiration Types of Respiration Aerobic respiration A metabolic process requires oxygen ( O 2 ) in the breakdown of glucose.PowerPoint Presentation: CELLULAR RESPIRATION AEROBIC Requires oxygen 1.Glycolysis 2.Krebs Cycle 3. Oxidative phosphorylation Does not require oxygen ANAEROBIC 1.Alcohol fermentation 2.Lactate fermentation RespirationAerobic Respiration: Aerobic Respiration C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O + Glucose 38 ATP http://www.google.com.my/imgres?q=aerobic+respiration+equation&hl=en&gbv=2&biw=1280&bih=587&tbm=isch&tbnid=aThSoPUZPeLyYM:&imgrefurAnaerobic Respiration: Plant C 6 H 12 O 6 2C 2 H 5 OH + 2CO 2 + ATP Animal C 6 H 12 O 6 2C 3 H 6 O 3 + ATP Ethanol (2C) Lactic acid (3C) Anaerobic RespirationPowerPoint Presentation: http://www.google.com.my/imgres?q=simple+cellular+respiration+diagram&hl=en&sa=X&gbv=2&biw=1280&bih=587&tbm=isch&tbnid=aT8vP93rIDC62M:&imgrefurlCellular Respiration: Cellular Respiration With the presence of O 2 Cells “split” sugar into a few chemical substances/molecules through a series of chemical reactions. Energy is released throughout the process Water and CO 2 are released as by products.PowerPoint Presentation: Oxidation of glucose which involves : Aerobic Respiration 1. Glycolysis , which occurs as in the cytosol. 2. The Krebs cycle , which takes place within the mitochondrial matrix. 3. Oxidative phosphorylation : take palace inner mitocondrial membranes.PowerPoint Presentation: Production of ATP Oxidative phosphorylation - because it is powered by the redox reaction that transfer an electron from organic compound to oxygen . - Through an electron transport chain . - 90% of the ATP generated by respiration. - Occurs in the inner mitochondrial membrane. ii. Su bstrate-level phosphorylation. - an enzyme transfers a phosphate group from an organic molecule to ADP, forming ATP - reaction of glycolysis and the Krebs cycle - A smaller amount of ATP - occurs in the cytosol and mitochondia matrix.Stage 1: Glycolysis : Stage 1: Glycolysis http://www.google.com.my/imgres?q=glycolysis+energy+investment+phase&start=123&num=10&hl=en&gbv=2&biw=1280&bih=587&addh=36&tbm=isch&tbnid=INFfLn3qO3U4YM:&imgrefurlContinue…: Continue… The first stage of cellular respiration “Splitting” of sugar Metabolic conversion of glucose into pyruvate Accompanied by production of ATP. Occurs in cytoplasmStage 2: Krebs Cycle: Stage 2: Krebs Cycle http://www.google.com.my/imgres?q=krebs+cycle&start=24&num=10&hl=en&gbv=2&biw=1280&bih=587&addh=36&tbm=isch&tbnid=LLNJ50p_F7U5nM:&imgrefurlContinue…: Continue… Series of chemical reactions Acetyl coenzyme A is completely degraded to CO 2 and water. With release of metabolic energy The energy used to produce ATP Occurs in the matrix of mitochondriaStage 3: Electron Transport Chain: Stage 3: Electron Transport Chain http://www.google.com.my/imgres?q=glycolysis+energy+investment+phase&start=123&num=10&hl=en&gbv=2&biw=1280&bih=587&addh=36&tbm=isch&tbnid=INFfLn3qO3U4YM:&imgrefurlContinue…: Continue… A series of chemical reactions Hydrogen or their electrons are passed along an electron transport chain Electron is passed along carrier molecules to oxygen to form water and ATP (energy) Occurs in inner mitochondrial membranesGLYCOLYSIS (splitting of glucose): GLYCOLYSIS (splitting of glucose) It breaks down glucose (6C) into two molecules of pyruvate (3C)PowerPoint Presentation: Glucose 2NADH 2 ATP Plasma membrane Cytoplasm Pyruvate Glycolysis MitochondriaPowerPoint Presentation: The location of glycolysis Glycolysis takes place in the cell cytoplasm ( in the cytosol ). The necessary enzymes are not found in the mitochondria. It is the first stage of both aerobic and anaerobic respiration and therefore takes place with or without oxygen.During these reactions there is a net gain of two ATP molecules plus four hydrogen atoms, the latter being taken up by two molecules of a coenzyme called NAD (nicotinamide adenine dinucleotide). : During these reactions there is a net gain of two ATP molecules plus four hydrogen atoms, the latter being taken up by two molecules of a coenzyme called NAD (nicotinamide adenine dinucleotide). 2 Pyruvate + 2 ATP + 2 NADH + 2H + 1 Glucose + 2 ADP + 2 Pi + 2 NAD +The pathway of glycolisis can be devided into two phases: The pathway of glycolisis can be devided into two phases 1. The energy investment phase 2. The energy payoff phasePowerPoint Presentation: Overall Biochemical pathway of glycolycis http://www.google.com.my/imgres?q=glycolysis+energy+investment+phase&num=10&hl=en&gbv=2&biw=1280&bih=587&tbm=isch&tbnid=fSgUoj9WRtMRDM:&imgrefurlPowerPoint Presentation: Glucose - Glyceraldehyde-3 phosphate / Dihydroxyacetone phosphate pathwayPowerPoint Presentation: Phosphorylation of glucose by ATP Catalyzed by hexokinase. Rearragement by isomerization Phoshorylation of fructose-1,6-biphosphate by ATP Catalyzed by phosphofructokinase The six-carbon molecule is split into two three-carbon molecules-one G3P, another that is cnverted into G3P in another reaction.PowerPoint Presentation: Glucose – Glyceraldehyde - 3 phosphate / Dihydroxyacetone phosphate pathway A phosphate-group transfer from one of the ATP molecules to glucose to form Glucose – 6 - phosphate A phosphate-group transfer from another ATP is used form intermediate fructose-1,6-bisphosphate.PowerPoint Presentation: The intermediate splits at once into two molecules,each with a three- carbon backbone. We can call these two PGAL/G3P. Each PGAL gives up two electrons and a hydrogen atom to NAD + , thus forming two NADH.PowerPoint Presentation: Glyceraldehyde-3-phosphate - Pyruvate pathwayPowerPoint Presentation: Oxidation followed by phosphorylation produces 2 NADH molecules of BPG Formation of 2 ATP molecules and leaves 2 3PG molecules by substrate level phosphorylation. Formation of 2PG by translocation of P-group Removal of water molecule yields 2 PEP molecules. H 2 O Formation of 2 ATP molecules and 2 pyruvate molecules by substrate level phosphorylation Glyceraldehyde-3-phosphate - Pyruvate pathway: Glyceraldehyde-3-phosphate - Pyruvate pathway Each PGAL gives up two electrons and a hydrogen atom to NAD + , thus forming two NADH. Each PGAL also combines with inorganic phosphate (P i ) in the cytoplasm and then makes a phosphate – group transfer to ADP. Thus two ATP have formed by the direct transfer of phosphate from two intermediate molecules that served as substrates for the reactions .PowerPoint Presentation: Formation of two ATP means the original energy investment of two ATP has been paid off. During the next two enzyme-mediated reactions , the two intermediates each release a hydrogen atom and –OH group, which combine to form water.PowerPoint Presentation: Two 3-phosphoenolpyruvate (PEP) molecules result. Each PEP makes a phosphate-group transfer to ADP. Once again two ATP have formed by subtrate-level phosphorylationPowerPoint Presentation: In sum, the net energy yield from glycolysis is two ATP for each glucose molecule entering the reaction. Two molecules of pyruvate the end products may enter the next set of reaction in an energy-releasing pathway.NET: NET Glucose 2 Pyruvate + 2H 2 O 2ADP + 2Pi 2ATP 2NAD 2NADH + 2H +THE LINK REACTION: OXIDATIVE DECARBOXYLATION OF PYRUVATE: THE LINK REACTION : OXIDATIVE DECARBOXYLATION OF PYRUVATE THE FATE OF PYRUVATE Depends upon the presence or absence of oxygen. If present, pyruvate enters the mitochondrion where it is completely oxidized.PowerPoint Presentation: When oxygen is present, the pyruvate moves out of the cytosol in which glycolysis took place and crosses the membrane into the matrix of the mitochondria. There, before entering the Krebs cycle proper, the pyruvate undergoes a transition stage, in which the two pyruvates are converted into two acetyl-coenzyme A (acetyl-CoA), two carbon dioxide molecules, and two NADHPowerPoint Presentation: During the series of eight reactions that make up the Krebs cycle, the two acetyl-coA molecules are oxidized, yielding two more molecules of carbon dioxide and 2 ATP. The carbon dioxide generated in these two processes is the carbon dioxide we exhale when we breathe.BEFORE THE KREBS CYCLE : BEFORE THE KREBS CYCLE After emerging from glycolysis , the two pyruvate are transported into the mitochondria. There, the pyruvate undergo a transition stage before entering the actual Krebs cycle. In this phase the pyruvate is transformed into acetyl-coenzyme A (acetyl-CoA), the starting product in the Krebs cycle. 2 Pyruvate + 2 coenzyme A + 2NAD + -> 2 acetyl-CoA +2CO 2 + 2 NADHPowerPoint Presentation: Source: Campbell.Reece. Biology sixth edition. 2002,164.Formation of Acetyl-CoA : Formation of Acetyl-CoA Acetyl-CoA is a common product of carbohydrate, lipid, and protein breakdown. It consists of an acetyl group attached to a coenzyme A molecule. Coenzyme A is a large molecule that contains a molecule of ADP with two side chain groups stemming from its phosphate arms. Acetyl groups attach to the end of these side chains.PowerPoint Presentation: The coenzyme A acts as a carrier of acetyl groups. When it is broken down by water, large amounts of energy are released, which drives the Krebs cycle. The most common way that acetyl-CoA is derived in the metabolic pathway is with the help of the pyruvate dehydrogenase multienzyme complex .PowerPoint Presentation: Source: Campbell.Reece. Biology sixth edition. 2002,166. Krebs cyclePowerPoint Presentation: The Krebs CyclePowerPoint Presentation: The Krebs Cycle pathway http://www.google.com.my/imgres?q=aerobic+respiration+equation&hl=en&gbv=2&biw=1280&bih=587&tbm=isch&tbnid=nikIdsaKkXHApM:&imgrefurlKrebs Cycle: Krebs Cycle Krebs cycle occurs in the matrix of mitochondria. Acetyl-CoA enters matrix of mitochondria Undergoes the process of Krebs cycle Release CO 2 as a waste product Produce ATP directly (substrate level phosphorylation) FADH 2 produced from reducing FAD NADH produced from reducing NAD +THE STEPS OF THE KREBS CYCLE : THE STEPS OF THE KREBS CYCLE 1. AcetyCoA + Oxaloacetate to Citrate Acetyl CoA adds its two-carbon fragment to oxaloacetate, producing citrate 2.Citrate to Isocitrate Citrate is convert to its isomer isocitrate by removal of one water molecule and addition of another.PowerPoint Presentation: 3. Isocitrate to α -Ketoglutarate Isocitrate loses a CO2 molecules, and the resulting compound is oxidized, reducing NAD+ to NADH 4. alpha-Ketoglutarate to Succinyl CoA Another Co2 is lost, and the resulting compound is oxidized, reducing NAD+ to NADH. The remaining molecule is then attached to coenzyme A by an unstable bond .PowerPoint Presentation: 5. Succinyl CoA to Succinate CoA is displaced by a phosphate group, which is transferred to GDP, forming GTP, and then to ADP, forming ATP (substrate – level phosphorylation) Reaction: Substrate-level phosphorylation 6. Succinate to Fumarate Two hydrogens are transferred to FAD to form FADH 2PowerPoint Presentation: 7. Fumarate to Malate Addition of a water molecule rearranges bonds in the substrate 8. Malate to Oxaloacetate The substrate is oxidized, reducing NAD+ to NADH and regenerating oxaloacetatePowerPoint Presentation: As the conclusion, for the Krebs Cycle : 8 NADH (2 from link reaction and 6 from the cycle itself) 2 FADH 2 and 2ATP (from 2 GTP) per glucose 6 CO 2 (2 from link reaction and 4 from the cycle itself) as waste product.Oxidative Phosphorylation: Oxidative Phosphorylation Only few ATP are produced by substrarate-level phosphorylation. 2 nett ATPs per glucose from glycolysis 2 ATPs per glucose in Kreb cycle. Most ATPs are produced by oxidative phosphorylation.PowerPoint Presentation: energy is conserved in NADH and FADH 2 Molecules of NAD+ are reduced to NADH for each acetate that enters the cycle In one oxidative reaction, electrons are transferred not to NAD+ but to a different electron acceptor FAD (flavin adenine dinucleotide)PowerPoint Presentation: The reduced form, NADH and FADH2 donates its electrons to the electron transport chain in the inner mitochondrial membrane The transfer of one pair of hydrogen atoms generates three ATP per molecule of NADH NADH + ½ O 2 -------> NAD + H 2 O 3 ADP + 3 phosphate --------> 3 ATPPowerPoint Presentation: The oxidation of one molecule of glucose needs two Krebs cycle, one Krebs cycle will produce three molecules NADH and one molecule FADH 2 So, for the six molecules of reduced NAD which are donate from two Krebs cycle will generate 6 x 3 = 18 ATPPowerPoint Presentation: But for the FADH 2 , the transfer of one pair of hydrogen atoms generate 2 ATP per molecules of FADH 2 FADH2 + ½ O 2 -------> FAD + H 2 O 2 ADP + 2 phosphate --------> 2 ATP So, for the two molecules of reduced FAD which are donates from two Krebs cycle will generate 2 x 2 = 4 ATP ELECTRON TRANSPORT CHAIN : ELECTRON TRANSPORT CHAIN The electron transport system located in the cristae of the mitochondria is a series of carriers that pass electrons from one to the other. Some of the protein carriers of the system are cytochrome molecules. Essentially the elctron transport system consists of three protein complexes ( NADH reductase, cytochrome b and cytochrome oxidase) and two protein mobile (coenzyme Q and cytochrome c)PowerPoint Presentation: The electrons that enter the electron transport system are carried by NADH and FADH 2 . Electrons are passed down the chain (low energy electron), to oxygen to form water When NADH gives up its electron, it becomes NAD + and the next carrier gains the electrons and is reduced. Each of carriers in turn become reduced and then oxidized as the electrons move down the system.PowerPoint Presentation: As each complex accepts and then donates an electron (oxidation-reduction reaction), it pumps hydrogen ions (H+, or simply protons) from the matrix to the intermembrane space Thus, energy is released and stored in the form a hydrogen ion (H + ) gradient.PowerPoint Presentation: Now, there is a greater concentration of H+ ions outside of the matrix H+ flow back into the matrix through the channels in ATP synthetase molecules in the membrane The energy released as H+ ions flow back into the ATP synthetase channel are then used to phosphorilate ADP into ATPPowerPoint Presentation: The above process is called oxidative phosphorylation refers to the production of ATP as a result of energy released through the electron transport system. Oxygen receives the energy-spent electrons from the last of carrier. After receiving electrons, oxygen combines with hydrogen ions and water forms.Electron Transport and Oxidative Phosphorylation Inner membrane of the mitochondria contains an electron transport system. : Electron Transport and Oxidative Phosphorylation Inner membrane of the mitochondria contains an electron transport system . http://www.google.com.my/imgres?q=electron+transport+system&hl=en&biw=1280&bih=587&gbv=2&tbm=isch&tbnid=tfBFPvcmwHfGnM:&imgrefurl· Electrons from NADH and FADH2 pass through the protein complexes, and cause protons to be pumped from the matrix to the inner membrane space. : · Electrons from NADH and FADH2 pass through the protein complexes, and cause protons to be pumped from the matrix to the inner membrane space. http://www.google.com.my/imgres?q=electron+transport+system&start=365&hl=en&biw=1280&bih=587&gbv=2&addh=36&tbm=isch&tbnid=jNYaYLrXY5xO_M:&imgrefurlPowerPoint Presentation: http://www.google.com.my/imgres?q=electron+transport+system,+complex&hl=en&gbv=2&biw=1280&bih=587&tbm=isch&tbnid=K0TSy8go3pPuNM:&imgrefurlATP synthetase, a protein complex of the inner membrane, uses the potential energy of the proton gradient to synthesize ATP. : ATP synthetase, a protein complex of the inner membrane, uses the potential energy of the proton gradient to synthesize ATP . http://www.google.com.my/imgres?q=oxidative+phosphorylation&start=273&um=1&hl=en&sa=N&gbv=2&biw=1280&bih=587&addh=36&tbm=isch&tbnid=SXhrnQBUuLmbCM:&imgrefurlPowerPoint Presentation: http://www.google.com.my/imgres?q=electron+transport+system&start=365&hl=en&biw=1280&bih=587&gbv=2&addh=36&tbm=isch&tbnid=jNYaYLrXY5xO_M:&imgrefurlCHEMIOSMOSIS: CHEMIOSMOSIS IN 1961 PETER Mitchell poposedthe chemiosmotc model. Mitchell proposed that electron transport and ATP synthesis are coupled by means of a proton gradient across the inner mitochondrial membrane.PowerPoint Presentation: As electrons transferred along the ETC in the inner mitochondrial membrane, energy released from the exergonic electron flow. H + / proton in the mitochondrial matrix, the actively pumped across the inner membrane to the intermembrane space. Thus the intermembrane space contains higher concentration.PowerPoint Presentation: The membrane phospholipid bilayer is impermeable to protons and prevents from leaking. Creates an electrochemical gradient across the inner membrane called proton-motive force. Protons diffuse through the ATP synthase ( transmembrane protein) complex, which causes the phosphorylation of ADPs producing ATPs.PowerPoint Presentation: Source:Interactive Concepts in Biology version 4.0 for Starr/Taggart's Biology: The Unity and Diversity of Life, Tenth EditionPowerPoint Presentation: As the H + accumulates on one side of a membrane, the concentration of H + creates an electrochemical gradient or potential difference across the membrane. The energized state of the membrane as a result of the charge seperation is called the proton-motive force.PowerPoint Presentation: Source:Interactive Concepts in Biology version 4.0 for Starr/Taggart's Biology: The Unity and Diversity of Life, Tenth EditionPowerPoint Presentation: The ETC creates enough proton-motive force to produce 3 ATPs for each electron pair that strips from NADH to oxygen. FADH 2 produced only 2 ATPs, since it donates electrons at a lower energy level to ETC.Comparison of the Four Phase of Aerobic Cellular Respiration : Comparison of the Four Phase of Aerobic Cellular Respiration 4 ATP + 2 NADH 2 ATP Converts glucose (6C) to 2 pyruvic acids (3C each) Glycolisis Gain, per glucose Cost, per glucose Molecular changes PhasePowerPoint Presentation: 2ATP + 6 NADH + 2 FADH2 None Acid citric (6C) Oxaloacetic Acid (4C) Krebs citric acid cycle 2 NADH None Pyruvic acid (3C) acetyl group (2C) Oxidation Of pyruvic acidPowerPoint Presentation: 34 ATP 2 ATP (to carry 2e - in NADH into mitocondria) NADH , FADH 2 NAD + , FAD + , electrons and protons * Realesed energy ATP * e - + H + + O 2- H 2 O Electron transportTOTAL = 34 +2 + 2 = 38 ATP (in heart muscle or active cells) TOTAL =36 (in all cells except heart) : TOTAL = 34 +2 + 2 = 38 ATP (in heart muscle or active cells) TOTAL =36 (in all cells except heart)PowerPoint Presentation: Total ATP are produced from 1 molecule of glucose: 2 ATP from Glycolysis 2 ATP from Krebs cycle 34 ATP from Oxidative-phosphorylationANAEROBIC RESPIRATION: ANAEROBIC RESPIRATION FERMENTATION AND ITS APPLICATIONFERMENTATION: FERMENTATION Anaerobic respiration is generation of ATP from glucose in absence of O 2 In fermentation, glucose only goes through the steps of Glycolysis 2 Pyruvates that are formed does not enter krebs cycle or electron transport chain THUS, only 2 ATP are produced per molecule of glucosePowerPoint Presentation: http://www.google.com.my/imgres?q=anaerobic+respiration&num=10&hl=en&gbv=2&biw=1280&bih=587&tbm=isch&tbnid=tzv5DH_orY6dUM:&imgrefurlThe importance of fermentation in industry: The importance of fermentation in industry Alcohol Fermentation Pyruvate CO2 Acetaldehyde NADH NAD+ + H+ EthanolPowerPoint Presentation: Source:Interactive Concepts in Biology version 4.0 for Starr/Taggart's Biology: The Unity and Diversity of Life, Tenth EditionAnaerobic in Animals: Anaerobic in Animals Lactic Acid Fermentation Piruvate NADH NAD + + H + Lactate no release of CO 2 carried out by human muscle cells when O2 is depleted; accumulation of lactate in muscle causes pain/fatiguePowerPoint Presentation: Source:Interactive Concepts in Biology version 4.0 for Starr/Taggart's Biology: The Unity and Diversity of Life, Tenth EditionPowerPoint Presentation: http://www.google.com.my/imgres?q=anaerobic+respiration&num=10&hl=en&gbv=2&biw=1280&bih=587&tbm=isch&tbnid=k6kx12iPTPSHBM:&imgrefurl You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.