Chapter 9, Problem 5
What is the oxidizing agent in the following reaction? Pyruvate+NADH+H+→Lactate+NAD+ a. oxygen b. NADH c. lactate d. pyruvate
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Which metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule? a. the citric acid cycle b. the electron transport chain c. glycolysis d. reduction of pyruvate to lactate
The final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is a. oxygen. b. water. c. NAD+. d. pyruvate.
In mitochondria, exergonic redox reactions a. are the source of energy driving prokaryotic ATP synthesis. b. provide the energy that establishes the proton gradient. c. reduce carbon atoms to carbon dioxide. d. are coupled via phosphorylated intermediates to endergonic processes
When electrons flow along the electron transport chains of mitochondria, which of the following changes occurs? a. The pH of the matrix increases. b. ATP synthase pumps protons by active transport. c. The electrons gain free energy. d. NAD+ is oxidized.
Most CO2 from catabolism is released during a. glycolysis. b. the citric acid cycle. c. lactate fermentation. d. electron transport.
MAKE CONNECTIONS Step 3 in Figure 9.9 is a major point of regulation of glycolysis. The enzyme phosphofructokinase is allosterically regulated by ATP and related molecules (see Concept 8.5). Considering the overall result of glycolysis, would you expect ATP to inhibit or stimulate activity of this enzyme? Explain. (Hint: Make sure you consider the role of ATP as an allosteric regulator, not as a substrate of the enzyme.)