Chapter 7 Hemoglobin:A Portrait of a Protein in Action 4 4 The structure of normal adult hemoglobin can be described as A)a tetramer composed of four myoglobin molecules. B) a tetramer composed of two aB dimmers. c) a tetramer composed of two a2 and two B2 dimers. D) a tetramer composed of two a2 and two y2 dimers. E)None of these accurately describe hemoglobin. Ans:B Section:7.1 5 Which of the following is correct concerning fetal hemoglobin? A)Fetal hemoglobin is composed of two a and two y subunits B)Fetal hemoglobin binds 2,3-BPG more tightly than normal adult hemoglobin. C) Fetal hemoglobin binds oxygen less than HbA at all pO2. D) Fetal hemoglobin does not exist in the T-form. E)None of the above. Ans:A Section:7.2 26.Hemoglobin-binding of oxygen is best described as a A) concerted model. B) Michaelis-Menten model. C) sequential model. D) combination of sequential and concerted models E) None of the above. Ans:D Section:7.2 27.2-3 Bisphosphoglycerate A) binds in the central cavity in the T-form of hemoglobin. B) preferentially binds to deoxyhemoglobin and stabilizes it. C) is present in the red blood cells. D) All of the above. E)None of the above. Ans:D Section:7.2 28.What is the Bohr effect? A)the ability of hemoglobin to retain oxygen when in competition with myoglobin B)the regulation of hemoglobin-binding by hydrogen ions and carbon dioxide C) the alteration of hemoglobin conformation during low oxygen stress D) All of the above. E)None of the above. Ans:B Section:7.3 29.Which of the following statements is correct for hemoglobin and oxygen transport? A)The oxygen binds to the proximal histidine residue of the globin chain B) Bonding of carbon dioxide to hemoglobin molecules increases the binding of oxygen. C) Hemoglobin binds more oxygen as the pH is lowered. D) Hemoglobin binds more oxygen at higher [BPG]concentrations. E)The binding of each O2 molecule to hemoglobin increases its affinity for the next O2 Ans:E Section:7.1Chapter 7 Hemoglobin: A Portrait of a Protein in Action 4 4 The structure of normal adult hemoglobin can be described as A) a tetramer composed of four myoglobin molecules. B) a tetramer composed of two αβ dimmers. C) a tetramer composed of two α2 and two β2 dimers. D) a tetramer composed of two α2 and two γ2 dimers. E) None of these accurately describe hemoglobin. Ans: B Section: 7.1 5 Which of the following is correct concerning fetal hemoglobin? A) Fetal hemoglobin is composed of two α and two γ subunits. B) Fetal hemoglobin binds 2,3-BPG more tightly than normal adult hemoglobin. C) Fetal hemoglobin binds oxygen less than HbA at all pO2. D) Fetal hemoglobin does not exist in the T-form. E) None of the above. Ans: A Section: 7.2 26. Hemoglobin-binding of oxygen is best described as a A) concerted model. B) Michaelis-Menten model. C) sequential model. D) combination of sequential and concerted models. E) None of the above. Ans: D Section: 7.2 27. 2-3 Bisphosphoglycerate A) binds in the central cavity in the T-form of hemoglobin. B) preferentially binds to deoxyhemoglobin and stabilizes it. C) is present in the red blood cells. D) All of the above. E) None of the above. Ans: D Section: 7.2 28. What is the Bohr effect? A) the ability of hemoglobin to retain oxygen when in competition with myoglobin B) the regulation of hemoglobin-binding by hydrogen ions and carbon dioxide C) the alteration of hemoglobin conformation during low oxygen stress D) All of the above. E) None of the above. Ans: B Section: 7.3 29. Which of the following statements is correct for hemoglobin and oxygen transport? A) The oxygen binds to the proximal histidine residue of the globin chain. B) Bonding of carbon dioxide to hemoglobin molecules increases the binding of oxygen. C) Hemoglobin binds more oxygen as the pH is lowered. D) Hemoglobin binds more oxygen at higher [BPG] concentrations. E) The binding of each O2 molecule to hemoglobin increases its affinity for the next O2 . Ans: E Section: 7.1