Cellular Respiration: Harvesting Chemical Energy Chapter 9 Cellular Respiration: Harvesting Chemical Energy Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings.

Energy and Respiration Newborn mammals have a specialized organ called brown fat, where cells burn fat to CO2 without capturing the energy to reduce electron carriers or make ATP. This energy may be used, instead, to synthesize glucose from CO2. directly power muscle contraction. provide energy for endergonic biosynthetic reactions. generate heat. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings.

Chemiosmosis: Uncouplers Some drugs known as uncouplers facilitate diffusion of protons across the mitochondrial inner membrane. When such a drug is added, what will happen to ATP synthesis and oxygen consumption? Both ATP synthesis and oxygen consumption will decrease. ATP synthesis will decrease; oxygen consumption will increase. ATP synthesis will increase; oxygen consumption will decrease. Both ATP synthesis and oxygen consumption will increase. ATP synthesis will decrease; oxygen consumption will stay the same. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings.

Electron Transport Chain and Respiration 1 Rotenone inhibits complex I (NADH dehydrogenase). When complex I is completely inhibited, cells will neither consume oxygen nor make ATP. not consume oxygen and will make ATP through glycolysis and fermentation. not consume oxygen and will make ATP only through substrate-level phosphorylation. consume less oxygen but still make some ATP through both glycolysis and respiration. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings.

Electron Transport Chain and Respiration 2 This graph shows the oxygen concentration in a sealed chamber containing isolated mitochondria plus citrate. The addition of ADP stimulates respiration by acting as a substrate for the F1 ATPase. stimulates respiration by speeding up glycolysis. inhibits respiration by depleting oxygen. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings.

Electron Transport Chain and Respiration 3 Rotenone inhibits complex I of the electron transport chain and thereby inhibits respiration. What compound X might restore respiration in the presence of rotenone? Hint: Examine the citric acid cycle. NADH isocitrate succinate malate pyruvate Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings.

Glycolysis To sustain high rates of glycolysis under anaerobic conditions, cells require functioning mitochondria. oxygen. oxidative phosphorylation of ATP. NAD+. All of the above are correct. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings.

Mitochondria and Alternative Energy Sources Petite mutants of yeast have defective mitochondria incapable of oxidative phosphorylation. What carbon sources can these mutants use to grow? glucose fatty acids pyruvate all of the above none of the above Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings.

Catabolism and Anaerobiosis During intense exercise, as muscles go into anaerobiosis, the body will increase its consumption of fats. proteins. carbohydrates. all of the above Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings.

Regulation of Metabolism How will a respiratory uncoupler affect the rates of glycolysis and the citric acid cycle? Both will increase. Both will decrease. Only glycolysis will increase because of fermentation. Only the citric acid cycle will increase. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings.

Evolution of Metabolic Pathways Glycolysis is found in all domains of life and is therefore believed to be ancient in origin. What can be said about the origin of the citric acid cycle, the electron transport chain, and the F1 ATPase? They evolved after photosynthesis generated free oxygen. They evolved before photosynthesis and used electron acceptors other than oxygen. Individual enzymes were present before photosynthesis but served other functions, such as amino acid metabolism. They evolved when the ancestral eukaryotes acquired mitochondria. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings.