Chem 454, Spring Exam II F, Faraday's constant, = kcal/mol V

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1 Name Chem 454, Spring Exam II F, Faraday's constant, = kcal/mol V 1. Analysis of electron transport pathway in a pathogenic gram-negative bacterium reveals the presence of six electron transport molecules with the reduction potentials listed below. Reduction potentials for pathogenic gram-negative bacterium Oxidant Reductant Electrons transferred E'o(V) NAD+ NADH Flavoprotein b (oxidized) Flavoprotein b (reduced) Cytochrome c (+3) Cytochrome c (+2) Ferroprotein (oxidized) Ferroprotein (reduced) FAD FADH Ubiquinone (oxidized) Ubiquinone (reduced) a. Predict the sequence of the carriers in this electron transport chain. b. Potentially, how many molecules of ATP can be generated under standard conditions when a pair of electrons is transported along this pathway. c. a. Write the balanced chemical equation for the reduction of NAD + by cytochrome c. b. Calculate the standard free energy change for this reaction. Is the reaction favorable under standard conditions? 1

2 2. a. Arrange the following electron transport chain components in their proper sequence. Ubiquinone Q-cytochrome c oxidoreductase NADH-Q oxidoreductase Cytochrome c oxidase Cytochrome c b. Which of these are mobile carriers? c. The NADH-Q oxidoreductase contains iron-sulfur clusters. Describe what these are and what they are used for. d. Which of these components contains the Q-cycle? Describe what the Q-cycle is. e. Which of these components does the respiratory inhibitor cyanide affect? f. Compare the effects of cyanide and dinitrophenol on a suspension of mitochondria containing ADP, Pi, and NADH. i) The effect on ATP synthesis by the suspension: ii) The effect on O 2 consumption by the suspension. 3. How many ATP molecules are generated during the complete oxidative degradation of each of the following to CO 2 and H 2 O? a. Acetyl-CoA b. Dihydroxyacetone phosphate c. Phosphoenolpyruvate 2

3 4. Describe how ATP Synthase is able to couple ATP synthesis to the proton gradient created by the electron transport chain. 5. The similarities between mitochondria and chloroplasts are obvious. Describe four ways in which they are opposite? a. b. c. d. 6. What role does plastocyanin play in photosynthesis? 7. What are the products of the light reactions of photosynthesis? 8. Describe the complex that connects photosystem II to photosystem I and discuss how it is similar to one of the complexes found in the electron transport chain. 9. Describe the role that the "special pair" plays in photosynthesis. 3

4 10. Name the three stages in the Calvin cycle a. b. c. 11. a. Using structural formulas, write a balanced chemical equation for the fixation stage of the Calvin cycle: b. What is the common name of the enzyme that carries out this reaction? c. Where does this reaction take place? d. What cofactor does this enzyme use? 12. a. The reduction stage of the Calvin cycle resembles what other pathway we have studied thus far? b. What is produced in this stage of the Calvin cycle? 13. a. What is the purpose of the third stage of the Calvin cycle? b. Describe in words what a transketolase reaction does? c. What cofactor is used in transketolase reactions 4

5 14. a. Using structural formulas, write a balanced chemical equation for the oxidative phase of the phosphate pentose pathway: b. What is the purpose of these reactions? c. What is the purpose of the nonoxidative phase of the pentose phosphate pathway? 15. a. What two tissues are involved in glycogen storage? b. What metabolic states to the hormones glucagons and epinephrine signal? c. In terms of glycogen metabolism, describe the events that follow the binding of ephinephrine to its target tissue. 16. Describe how glycogen synthesis and degradation are reciprocally regulated by both glucagon and insulin. 5

Physiological Chemistry II Exam IV Dr. Melissa Kelley April 13, 2004

Name Write your name on the back of the exam Physiological Chemistry II Exam IV Dr. Melissa Kelley April 13, 2004 This examination consists of forty-four questions, each having 2 points. The remaining