Cellular Respiration and Fermentation 7 Cellular Respiration and Fermentation Questions prepared by Brad Stith, University of Colorado Denver Jung Choi, Georgia Institute of Technology

Cellular respiration can best be described as using energy released from breaking high-energy covalent bonds in organic molecules to make ATP. taking electrons from food and giving them to phosphate to make ATP. taking electrons from food and giving them to oxygen to make water and using the energy released to make ATP. converting higher-energy organic molecules to lower-energy organic molecules and using the energy released to make ATP. Answer: C This question relates to Concept 7.1.

Cellular respiration can best be described as using energy released from breaking high-energy covalent bonds in organic molecules to make ATP. taking electrons from food and giving them to phosphate to make ATP. taking electrons from food and giving them to oxygen to make water and using the energy released to make ATP. converting higher-energy organic molecules to lower-energy organic molecules and using the energy released to make ATP. 3

Which statement about glycolysis is true? It splits water. It splits glucose. It occurs in the cytoplasm. It makes the most ATP compared to the two other steps. It splits lipids. Answer: C 4

Which statement about glycolysis is true? It splits water. It splits glucose. It occurs in the cytoplasm. It makes the most ATP compared to the two other steps. It splits lipids. 5

Which statement about the citric acid cycle is true? It occurs during the movement from the cytosol through the mitochondrial membranes. It makes ATP through substrate-level phosphorylation. It makes the most ATP compared to the two other steps. It occurs in the cytoplasm. It splits glucose. Answer: B 6

Which statement about the citric acid cycle is true? It occurs during the movement from the cytosol through the mitochondrial membranes. It makes ATP through substrate-level phosphorylation. It makes the most ATP compared to the two other steps. It occurs in the cytoplasm. It splits glucose. 7

functioning mitochondria oxygen oxidative phosphorylation of ATP NAD What do cells require to sustain high rates of glycolysis under anaerobic conditions? functioning mitochondria oxygen oxidative phosphorylation of ATP NAD All of the above are correct. Answer: D This question corresponds to Concept 7.5. 8

functioning mitochondria oxygen oxidative phosphorylation of ATP NAD What do cells require to sustain high rates of glycolysis under anaerobic conditions? functioning mitochondria oxygen oxidative phosphorylation of ATP NAD All of the above are correct. 9

Both ATP synthesis and oxygen consumption will decrease. Drugs known as uncouplers facilitate diffusion of protons across the membrane. Brown fat can generate heat without ATP by using uncouplers. With an uncoupler, what will happen to ATP synthesis and oxygen consumption if the rates of glycolysis and the citric acid cycle stay the same? 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. Answer: E This question corresponds to Concept 7.4. 10

Both ATP synthesis and oxygen consumption will decrease. Drugs known as uncouplers facilitate diffusion of protons across the membrane. Brown fat can generate heat without ATP by using uncouplers. With an uncoupler, what will happen to ATP synthesis and oxygen consumption if the rates of glycolysis and the citric acid cycle stay the same? 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. 11

actively transport H into the intermembrane space. The energetic electron, taken from glucose or a breakdown product of glucose, is stripped of its energy to actively transport H into the intermembrane space. actively transport NAD into the intermembrane space. actively transport Na into the matrix. power facilitated diffusion of H into the matrix. actively transport H into the matrix. Answer: A This question corresponds to Concept 7.4, Figure 7.15. Respiration will occur only through alternative substrates such as FADH2 that are oxidized downstream of complex I. 12

actively transport H into the intermembrane space. The energetic electron, taken from glucose or a breakdown product of glucose, is stripped of its energy to actively transport H into the intermembrane space. actively transport NAD into the intermembrane space. actively transport Na into the matrix. power facilitated diffusion of H into the matrix. actively transport H into the matrix. 13

allowing Na to move down its electrochemical gradient ATP synthase at the inner mitochondrial membrane makes ATP by which of the following methods? allowing Na to move down its electrochemical gradient allowing H to move against its electrochemical gradient facilitated diffusion of H active transport of H active transport of Na Answer: A This question corresponds to Concept 7.4, Figure 7.15. Respiration will occur only through alternative substrates such as FADH2 that are oxidized downstream of complex I. 14

allowing Na to move down its electrochemical gradient ATP synthase at the inner mitochondrial membrane makes ATP by which of the following methods? allowing Na to move down its electrochemical gradient allowing H to move against its electrochemical gradient facilitated diffusion of H active transport of H active transport of Na 15

to synthesize glucose from CO2 to directly power muscle contraction 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. How can this energy be used instead? to synthesize glucose from CO2 to directly power muscle contraction to provide energy for endergonic biosynthetic reactions to generate heat Answer: D This question corresponds to Concepts 7.1, 7.4, and 7.6. It could be used with the question on uncouplers: Thermogenin is a proton channel in the inner membrane that uncouples respiration from ATP synthesis to generate heat. Some bees and some philodendron flowers use similar mechanisms to generate heat. 16

to synthesize glucose from CO2 to directly power muscle contraction 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. How can this energy be used instead? to synthesize glucose from CO2 to directly power muscle contraction to provide energy for endergonic biosynthetic reactions to generate heat 17

What is the purpose of fermentation reactions? to regenerate NAD so glycolysis can continue to make alcohol or lactic acid that cells can metabolize for energy under anaerobic conditions to make additional ATP when respiration can’t make ATP fast enough to slow down cellular oxygen consumption when oxygen is scarce to make organic molecules that cells can store until oxygen becomes available Answer: A This question relates to Concept 7.5. 18

What is the purpose of fermentation reactions? to regenerate NAD so glycolysis can continue to make alcohol or lactic acid that cells can metabolize for energy under anaerobic conditions to make additional ATP when respiration can’t make ATP fast enough to slow down cellular oxygen consumption when oxygen is scarce to make organic molecules that cells can store until oxygen becomes available 19

alcoholic fermentation the citric acid cycle During intense exercise, muscles lack sufficient oxygen, so what will the muscles use? alcoholic fermentation the citric acid cycle only glycolysis, with NAD not utilized lactic acid fermentation chemiosmosis Answer: D This question corresponds to Concepts 7.5 and 7.6. 20

alcoholic fermentation the citric acid cycle During intense exercise, muscles lack sufficient oxygen, so what will the muscles use? alcoholic fermentation the citric acid cycle only glycolysis, with NAD not utilized lactic acid fermentation chemiosmosis 21