Exam 7: Hemoglobin: a Portrait of a Protein in Action

A) CO₂
B) H₂CO₃
C) HCO₃^-
D) CO₃^2-
E) None of the answers is correct.

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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 answers is correct.

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A) two $\alpha$ chains and two $\beta$ chains.
B) two $\alpha$ chains and two $\gamma$ chains.
C) two $\alpha$ chains and two $\beta$ chains
D) two $\alpha$ chains and two $\delta$ chains
E) four $\beta$ chains

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A) In the sequential model, the binding of a ligand changes the conformation of the subunit to which it binds, in turn inducing a change in neighboring subunits.
B) All known allosteric proteins exhibit either the concerted or sequential model exclusive of the other.
C) Both models incorporate a low affinity T-state and a higher affinity R-state.
D) Both models explain the sigmoid-shaped binding curve.
E) In the concerted model, all molecules exist either in the T-state or the R-state.

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B

A) amide
B) imine
C) carbonate
D) carbamate
E) None of the answers is correct.

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A) thalassemia
B) pernicious anemia
C) megaloblastic hereditary anemia
D) acanthocytosis
E) aplastic anemia

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A

A) HCO₂H
B) HCO₃^-
C) CO₃^2-
D) H₂CO₃^-
E) None of the answers is correct.

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A) a decreased production of α chains of hemoglobin.
B) a substitution of a Glu residue for a Phe residue at the β6 position.
C) the loss of the heme group because the proximal His is oxidized.
D) a substitution of a Val residue for a Glu residue at the β6 position.
E) a substitution of Glu residue for His at the C-terminal of the α chain.

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Hemoglobin binds oxygen in a positive cooperative manner.This allows it to become saturated in the lungs,where oxygen pressure is high.When the hemoglobin moves to tissues,the lower oxygen pressure induces it to release oxygen and thus deliver oxygen where it is needed.

A) concerted model.
B) Michaelis-Menten model.
C) sequential model.
D) combination of sequential and concerted models.
E) None of the answers is correct.

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The bonding between the iron and oxygen ...

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A) Protein Y exhibits tighter oxygen binding than protein X.
B) Protein Y would function as a better oxygen-transport protein than protein X.
C) Protein X exhibits cooperative binding, whereas Y does not.
D) Protein Y corresponds to myoglobin, and protein X corresponds to hemoglobin.
E) Protein X contains multiple binding sites.

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A) metmyoglobin
B) oxyhemoglobin
C) carboxyhemoglobin
D) leghemoglobin
E) None of the answers is correct.

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A) Protein Y exhibits tighter oxygen-binding than protein X.
B) Protein Y corresponds to fetal hemoglobin, and protein X corresponds to normal adult hemoglobin.
C) Protein X corresponds to fetal hemoglobin, and protein Y corresponds to normal adult hemoglobin.
D) Protein X corresponds to myoglobin, and protein Y corresponds to hemoglobin.
E) None of the answers is correct.

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Metmyoglobin is formed when the heme iro...

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