tailieunhanh - Biochemistry, 4th Edition P113

Biochemistry, 4th Edition P113. Continuing Garrett and Grisham's innovative conceptual and organizing framework, "Essential Questions," BIOCHEMISTRY guides students through course concepts in a way that reveals the beauty and usefulness of biochemistry in the everyday world. Streamlined for increased clarity and readability, this edition also includes new photos and illustrations that show the subject matter consistently throughout the text. New end-of-chapter problems, MCAT practice questions, and the unparalleled text/media integration with the power of CengageNOW round out this exceptional package, giving you the tools you need to both master course concepts and develop critical problem-solving skills you can draw upon. | Abbreviated Answers to Problems A-23 lethal dose of cyanide is small compared with the total amount of hemoglobin in the body. Even though a small amount of hemoglobin is sacrificed by sequestering the cyanide in this manner a lethal dose of cyanide can be neutralized in this manner without adversely affecting oxygen transport. 5. You should advise the wealthy investor that she should decline this request for financial backing. Uncouplers can indeed produce dramatic weight loss but they can also cause death. Dinitrophenol was actually marketed for weight loss at one time but sales were discontinued when the potentially fatal nature of such therapy was fully appreciated. Weight loss is best achieved by simply making sure that the number of calories of food eaten is less than the number of calories metabolized. A person who metabolizes about 2000 kJ about 500 kcal more than he or she consumes every day will lose about a pound in about 8 days. 6. The calculation in Section assumes the same conditions as in this problem 1 pH unit gradient across the membrane and an electrical potential difference of V . The transport of 1 mole of H across such a membrane generates kJ of energy. For three moles of H the energy yield is kJ. Then from Equation we have 69 900 J mol 30 500 J mol RT ln ATP ADP Pi 39 400 J mol RT ln ATP ADP Pi ATP ADP Pi X 106 M-1 at 37 C. In the absence of the proton gradient this same ratio is X 10 11 M 1 at equilibrium 7. The succinate fumarate redox couple has the highest that is most positive reduction potential of any of the couples in glycolysis and the TCA cycle. Thus oxidation of succinate by NAD would be very unfavorable in the thermodynamic sense. Oxidation of succinate by NAD 4 o V AG 67 500 J mol. On the other hand oxidation of succinate is quite feasible using enzyme-bound FAD. Oxidation of succinate by FAD A o 0 AG 0 depending on the exact reduction potential for bound FAD. 8. a. kJ mol. b. Keq