Presentation on theme: "Ch. 8: Harvesting Energy - Glycolysis & Cellular Respiration"— Presentation transcript:
1 Ch. 8: Harvesting Energy - Glycolysis & Cellular Respiration - CR IntroCase Study Athletes Boost Counts.pdf
2 8.1: How Do Cells Obtain Energy? photosynthesis ultimate source of energy.photosynthetic organisms capture sun’s energy and store it in form of glucose6 CO2 6 H2O light energy C6H12O6 6 O2nearly ALL organisms use glycolysis & cellular respiration to break down sugar and capture the released energy as ATPC6H12O6 6 O2 6 CO2 6 H2O ATP energy heat energycells break down glucose in 2 stagesglycolysis liberates a small quantity of ATPcellular respiration produces a lot of ATP
3 energy from sunlight photosynthesis C6H12O6 6 CO2 6 H2O 6 O2 cellular Figure 8-1 Photosynthesis provides the energy released during glycolysis and cellular respirationenergy from sunlightphotosynthesisC6H12O66CO26H2O6O2cellularrespirationglycolysisATP3
4 8.1: How Do Cells Obtain Energy? Glucose is a key energy-storagemoleculeall cells metabolize glucoseplants covert glucose sucrose or starchhumans & many other animals store energy in glycogen & fatglycogenstarch
5 8.2: What Happens During Glycolysis Glycolysis (“sweet”, “split apart”): series of enzyme catalyzed reactions that splits 6-C glucose into 2 molecules of pyruvateEnergy investment stage:1 glucose + 2 ATP 1 fructose bisphosphateEnergy harvesting stage:fructose bisphosphate 2 G3P pyruvate2 ATP generated from each G3P but 2 were used to form fructose bisphosphate (net gain ATP = 2/glucose)2 G3P donates 2 e- & a H+ ion to NAD+ NADH
7 Ch. 8.3: What Happens During Cellular Respiration Cellular respiration: breaks down 2 pyruvate molecules into 6CO2 & 6 H2O and produces 32 ATP in the mitochondriahttps://www.youtube.com/watch?v=pOfyuoa0Ywc –Mitochondria structure3 stages of cellular respirationPyruvate prep-step & Krebs cycle2. ETC3. Chemiosmosis
8 Formation of acetyl CoA (2C acetyl + coenzyme A): 1a- Pyruvate Prep Steppyruvate (synthesized in cytosol during glycolysis) is actively transported into matrixFormation of acetyl CoA (2C acetyl + coenzyme A):pyruvate splits releasing CO2and leaves behind an acetyl groupb. acetyl group reacts with CoA acetyl CoAc. transfers liberated energy toNAD+ NADH
9 1b – Krebs Cycle or Citric Acid Cycle a. Acetyl CoA + 4C molecule 6C citrate (citric acid) moleculeAcetyl CoAreleased and recycledc. Enzymes break downacetyl group CO2 + 4C moleculed. chemical energycaptured in NADH,FADH2, ATPCO2 becomes awaste product2 pyruvate generates (mitochondrial matrix reactions) 2 ATP, 8 NADH, 2 FADH2 & 6 CO2Formation ofacetyl CoANADHNADFADFADH2CO2coenzyme Acoenzyme AKrebscycleacetyl CoANADNADHADPATP
10 Krebs Cycle or Citric Acid Cycle https://www.youtube.com/watch?v=JPCs5pn7UNI - Krebs Song
11 2 - ETCseries of electron transporting molecules embedded in inner mitochondrial membrane(matrix)1 H2O per 2 e-ADPATPhttps://www.youtube.com/watch?v=xbJ0nbzt5Kw – ETC VideoDonate e- & H+P- ETC SongNADHFADH2NADFADATPsynthase(innermembrane)ETCEnergy either1-lost as heat2-pumps in H+(intermembrane space)11
12 Boosting Blood Counts: Do Cheaters Prosper? When people and other animals exercise vigorously, they are unable to get enough air into their lungs, enough oxygen into their blood, and enough blood circulating to their muscles to allow cellular respiration to meet all their energy needs. As oxygen demand exceeds oxygen supply, muscles must rely on glycolysis (which yields far less ATP than does cellular respiration) for periods of intense exercise. This explains why some athletes, desperate for a competitive edge, may turn to illegal blood doping to increase the ability of their blood to carry oxygen .https://screen.yahoo.com/tyler-hamilton-blood-doped ht - Tyler Hamilton (Armstrong teammate)
13 https://www.youtube.com/watch?v=3y1dO4nNaKY ATP synthase 3 - ChemiosmosisChemiosmosis: process by which energy is used to generate a concentration of H+ to generate ATPhttps://www.youtube.com/watch?v=3y1dO4nNaKY ATP synthasecarrier proteins transport1. ATP : matrix intermembrane space2. ADP : intermembrane space matrixATP molecules diffuse through large pores inouter mitochondrial membrane and into cytosola person produces, uses, and then regeneratesthe equivalent of roughly his or her body weight ofATP dailyChemiosmosis yields 32 ATP
14 Why is Cyanide So Deadly? common murder weapon where victims of the poison die almost instantly blocks the last protein in the ETC which is an enzyme that combines electrons with oxygenif energy-depleted electrons are not carried away by oxygen, they act like a plug preventing high energy electrons from traveling the ETCno more H+ can be pumped acrossmembrane and therefore, no chemiosmosis can kill within a few minutes
16 Cellular Respiration Can Extract Energy from a Variety of Molecules Glucose sucrose, starch, protein & fat can enter CR stages and be broken down to produce ATPATP not used for long term storage b/c it becomes unstableFats stable and store 2X as much energy for their weight as carbsCandy bar (sucrose) glucose + fructose (metabolized in liver) G3PIf cells have plenty of ATP some G3P diverted from CR to make glycerol.Excess acetyl CoA used to make fatty acidshttps://www.youtube.com/watch?v=EwqNp9cO_-4 – Why Can You Get Fat by Eating Sugar?
17 8.4 What Happens During Fermentation? glycolysis – used by virtually all organismsearlier life forms appeared under anaerobic conditions (no O2) existingbefore photosynthesissome organisms lack enzyme for cellular respiration and rely solely onfermentation while others live in places with little to no O2- stomachs and intestines of animals- deep in soil, bogs, etc2 types of fermentationa. lactic acid fermentation: pyruvate lactic acidb. alcoholic fermentation: pyruvate ethanol & CO2
18 fermentation allows NAD+ to be recycled when O2 is absent production of NAD+ is necessary for glycolysis to continuedoes not produce an ATPLactic Acid FermentationNO O2 = muscles stopmuscles rely on glycolysis for2 ATP/glucose moleculemuscle cells ferment resultingpyruvate to lactate using e- & H+from NADHmicroorganisms milk to yogurt,sour cream, cheesehttps://www.youtube.com/watch?v=LDh1O4Zk7Xc – Fermentation Video
19 Figure 8-8 Glycolysis followed by lactic acid fermentation 2NAD2NADH2NADH2NAD(glycolysis)(fermentation)1 glucose2 pyruvate2 lactate2ADP2ATP19
20 Blood Doping: Do Cheaters Prosper? Why is the average speed of the 5,000-meter run in the Olympics slower than that of the 100-meter dash? During the dash, runner’s leg muscles use more ATP than cellular respiration can supply. But anaerobic fermentation can only provide ATP for a short dash. Longer runs must be aerobic, and thus slower, to prevent lactic acid buildup from causing extreme fatigue, muscle plain, and cramps.Sprinters rely on lactic acid fermentationin their leg muscle cells for their final burst of speed.https://www.youtube.com/watch?v=DGq94gpKEbg – Lactic Acid and Fatigue
21 Alcoholic Fermentation? many microorganisms like yeast engage in alcoholic fermentation under anaerobic conditionsgenerates alcohol and CO2 from pyruvatelike in lacticacid fermentation,NAD+ must beregenerated toallow glycolysisto continuehttps://www.youtube.com/watch?v=4SosPuWAg7gMaking ginerale2NAD2NADH2NADH2NAD(glycolysis)(fermentation)1 glucose2 pyruvate2 ethanol2 CO22ADP2ATP
22 Blood Doping: Do Cheaters Prosper? Although runners who do the 100-meter dash rely heavily on lactic acid fermentation to supply ATP, long distance athletes including cyclists, marathon runners, and cross-country skiers must pace themselves. They must rely on aerobic cellular respiration for most of the race, saving the anaerobic spring for the finish. Training for distance events focuses on increasing the capacity of the athletes’ respiratory and circulatory systems to deliver enough oxygen to their muscles. Blood doping most often occurs among distance athletes seeking to increase the oxygen carrying capacity of their blood so that cellular respiration can generate the maximum amount of ATP from glucose.The EPO-mimicking drug CERA – that the disgraced cyclist Ricco now admits having taken –helped keep his muscles supplied with ATP by stimulating overproduction of oxygen-carrying red blood cells. In the particularly demanding mountain stages of the Tour de France, which Ricco won, his clean competitors were at a disadvantage because their leg muscles became painfully laden with lactate from fermentation sooner than Ricco’s did.
23 Blood Doping: Do Cheaters Prosper? Because EPO is produced naturally in the human body, its abuse is hard to detect. CERA, developed for use by people with anemia (who have too few red blood cells), was new on the market at the time of the 2008 Tour de France, and Ricco may have assumed it would be undetectable. But CERA’s manufacturer, the pharmaceutical firm Hoffman-La Roche, had provided samples of the drug to the World Anti-Doping Agency before it was marketed, allowing researchers to develop urine tests to identify users. This led to Ricco’s exposure and disgrace, and his team’s devastating disappointment.1. Some athletes move to high-altitude locations to train for races run at lower altitudes because the low oxygen levels at high altitudes stimulate increased production of red blood cells.Is this cheating? Explain your reasoning.2. Advances in gene therapy may one day make it possible to modify athletes’ cells so that they have extra copies of the gene that produces EPO.