Cellular Respiration

7.4 Anaerobic RespirationCellular Respiration1Anaerobic RespirationRecall anaerobic respiration occurs in the ABSENCE of O2Two methods- alcohol fermentation (plants)- lactic acid fermentation (animals)Both methods begin with GLYCOLYSIS

2Alcohol FermentationStarts with glycolysisGlucose is metabolized to pyruvateA net of 2 ATP is madeDuring alcoholic fermentationPyruvate is reduced to form ethanolCarbon dioxide is releasedNAD+ is recycled so glycolysis can continueYeast do thisLeavened bread Sparkling wine

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4Lactic Acid FermentationStarts with glycolysisGlucose is metabolized to pyruvatePyruvate is reduced to form lactic acidNADH transfers H+ ions to pyruvate, regenerating NAD+A net of 2 ATP is madeNo carbon dioxide is releasedMuscle cells have the enzymes to do this, but brain cells do not

Muscle cells can survive brief periods of oxygen deprivation, but brain cells cannotLactic acid burn in muscles

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7Maximum Oxygen UptakeAerobic Fitness: measure of the ability of the heart, lungs, and bloodstream to supply O2 to the cells of the body during physical activityVO2 maxA maximum rate at which an individual can consume O2 during maximal exertionPeak aerobic powermilliliters per kilogram per minute(ml/kg/min)

8Exercise and VO2 maxMoving from rest to exercise energy requirementsMetabolism increases in direct proportion to rate of workAs demand for energy increases so does oxygen consumption (remember the role of oxidation to produce ATP to do work)VO2 eventually peaks = VO2 maxVO2 may remain constant at max or drop slightly even through work intensity continues to increaseAverage VO2 max is 35mL/kg/minTop athletes VO2 max is 70 mL/kg/min

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10Supplements and ToxinsCreatine phosphatedonates its high energy phosphate to the production of ATPCreatine phosphate + ADP creatine + ATPincrease in diet may help to store creatine phosphate in muscle cells (creating a reservoir of phosphate ready for ATP production)potentially also acts as a buffer in muscle cells against lactic acid

11Carbon monoxide (CO)combines with hemoglobin preventing O2 from binding with red blood cellsaffinity between hemoglobin and CO is about 230 times stronger than the affinity between hemoglobin and O2hemoglobin will bond with CO before it will with O2No oxgyen available means the ETC terminatesLow ATP production results in cell death 12Cyanide and Hydrogen Sulfideinhibit oxygen consumption by mitochondriastopping cellular respiration13