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Cellular Respiration. Cellular Respiration. Cellular Respiration (aerobic) – process that releases energy by breaking down glucose and other food molecules; O 2 is required 6O 2 + C 6 H 12 O 6 6CO 2 + 6H 2 O + ATP 3 Major sets of reactions – glycolysis , Krebs Cycle,
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Cellular Respiration • Cellular Respiration (aerobic) – process that releases energy by breaking down glucose and other food molecules; O2 is required • 6O2 + C6H12O6 6CO2 + 6H2O + ATP • 3 Major sets of reactions – glycolysis, Krebs Cycle, • electron transport chain • Fermentation (anaerobic) – process that releases energy from food without O2 – Fig. 9-4 • 2 Major sets of reactions – glycolysis, fermentation • NADH – an electron carrier molecule Chemical Pathways
Anaerobic RespirationFermentation Glycolysis – breakdown of glucose to produce: 2 pyruvic acid, 2 NADH, **net gain of 2 ATP
Glycolysis • http://www.youtube.com/watch?v=3GTjQTqUuOw
Anaerobic RespirationFermentation Fermentation – conversion of pyruvic acid to some end product ** no ATP produced
Anaerobic RespirationFermentation Lactic acid fermenation – end product is lactic acid (ex. Animal cells, lactic acid bacteria)
Anaerobic RespirationFermentation Alcoholic fermentation – end products are ethanol & CO2 (ex. Bacteria & yeast)
Anaerobic RespirationFermentation **For each molecule of glucose only 2 ATP are produced during anaerobic respiration.**
Aerobic Respiration Glycolysis – exact same steps as in anerobic respiration; takes place in the cytoplasm; At the end of glycolysis approximately 90% of the energy is still stored in pyruvic acid molecules These two pyruvic acid molecules will enter the Krebs Cycle (citric acid cycle)
Aerobic Respiration Glycolysis
Aerobic Respiration Krebs cycle (citric acid cycle) – the two pyruvic acids molecules that are products of glycolysis are broken down in a series of energy-extracting reactions Takes place in the matrix of the mitochondria
Aerobic Respiration Krebs cycle (con’t) 1. Citric Acid Production – pyruvic acid is completely oxidized to produce: a. 2 NADH b. 2 CO2 c. 2 Citric Acid molecules
Aerobic Respiration Krebs cycle (con’t) 2. Energy extraction – series of chemical reactions (cycle) to produce (for each pyruvic acid) a. 1 ATP (2 ATP total) b. 3 NADH (6 NADH total) c. 1 FADH (2 FADH total) d. 2 CO2 (4 CO2 total) http://www.youtube.com/watch?v=KAjUsiZWywk&feature=related
Aerobic Respiration Electron Transport Chain – uses the high energy electrons from glycolysis and the Krebs cycle to synthesize ATP from ADP and Pi MOST of the energy produced from the breakdown of glucose occurs here (32/34 ATP molecules) O2 is the final electron acceptor
Aerobic Respiration ***For each molecule of glucose, 36/38 ATP are produced during aerobic respiration*** ***Much more energy efficient than anaerobic respiration****
Respiration of Fats & Proteins Fats and proteins are broken down at various points along respiratory pathway Proteins produce about the same amount of ATP as glucose Fats produce about twice as much energy as glucose
Energy & Exercise The body uses ATP from 3 basic sources; ATP stored in muscle cells, and ATP produced by aerobic & anaerobic respiration The ATP stored in muscle cells only lasts for the first few seconds of activity.
Energy & Exercise ATP produced by anaerobic respiration is used up in about 90 seconds. Oxygen debt is the amount of O2 required to convert lactic acid to glucose. Aerobic respiration produces the ATP to sustain activities that go on longer. That is why athletes must pace themselves.
