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Cellular Respiration. 7.4 Anaerobic Respiration. Anaerobic Respiration. Recall anaerobic respiration occurs in the ABSENCE of O 2 Two methods - alcohol fermentation (plants) - lactic acid fermentation (animals) Both methods begin with GLYCOLYSIS. Alcohol Fermentation.
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Cellular Respiration 7.4 Anaerobic Respiration
Anaerobic Respiration • Recall anaerobic respiration occurs in the ABSENCE of O2 • Two methods- alcohol fermentation (plants)- lactic acid fermentation (animals) • Both methods begin with GLYCOLYSIS
Alcohol Fermentation • Starts with glycolysis • Glucose is metabolized to pyruvate • A net of 2 ATP is made • During alcoholic fermentation • Pyruvateis reduced to form ethanol • Carbon dioxide is released • NAD+ is recycled so glycolysis can continue • Yeast do this • Leavened bread • Sparkling wine
Lactic Acid Fermentation • Starts with glycolysis • Glucose is metabolized to pyruvate • Pyruvate is reduced to form lactic acid • NADH transfers H+ ions to pyruvate, regenerating NAD+ • A net of 2 ATP is made • No carbon dioxide is released • Muscle cells have the enzymes to do this, but brain cells do not • Muscle cells can survive brief periods of oxygen deprivation, but brain cells cannot • Lactic acid “burn” in muscles
Maximum Oxygen Uptake • Aerobic Fitness: measure of the ability of the heart, lungs, and bloodstream to supply O2 to the cells of the body during physical activity • VO2 max • A maximum rate at which an individual can consume O2 during maximal exertion • Peak aerobic power • milliliters per kilogram per minute(ml/kg/min)
Exercise and VO2 max • Moving from rest to exercise ↑ energy requirements • Metabolism increases in direct proportion to rate of work • As demand for energy increases so does oxygen consumption (remember the role of oxidation to produce ATP to do work) • VO2 eventually peaks = VO2 max • VO2 may remain constant at max or drop slightly even through work intensity continues to increase • Average VO2 max is 35mL/kg/min • Top athletes’ VO2 max is 70 mL/kg/min
Supplements and Toxins • Creatine phosphate • donates its high energy phosphate to the production of ATP Creatine phosphate + ADP ↔ creatine + ATP • increase 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
Carbon monoxide (CO) • combines with hemoglobin preventing O2 from binding with red blood cells • affinity between hemoglobin and CO is about 230 times stronger than the affinity between hemoglobin and O2 • hemoglobin will bond with CO before it will with O2 • No oxgyen available means the ETC terminates • Low ATP production results in cell death
Cyanide and Hydrogen Sulfide • inhibit oxygen consumption by mitochondria • stopping cellular respiration