Deck 10: Hemoglobin and the Hemoglobinopathies

Question 1

Which of the following statements is true of the sickle cell trait-associated form of hemoglobin,Hb S?

A) It is characterized by a relative deficiency of a chains versus b chains
B) It has increased oxygen binding affinity relative to Hb A
C) It is less soluble than Hb A
D) It is dominant to Hb A
E) Therapeutic approaches have been highly successful in alleviating phenotypes associated with Hb S

Answer 1

It is less soluble than Hb A

Question 2

Which of the following statements is true regarding the a1 and a2 globin chains?

A) They are identical at the nucleotide and amino acid sequence level
B) They differ at the nucleotide level but are identical at the amino acid level
C) a1 pairs only with b1, and a2 pairs only with b2
D) a1 is expressed in the fetus, and a2 is expressed after birth
E) a2 is a pseudogene of a1

Answer 2

They differ at the nucleotide level but are identical at the amino acid level

Question 3

The complete absence of a globin production gives rise to which phenotype?

A) Sickle cell disease
B) Hb H disease
C) b-thalassemia
D) Hydrops fetalis
E) Normal adult hemoglobin production

Answer 3

Hydrops fetalis

Question 4

The HbA form of hemoglobin consists of which globin chains?

A) 1 a, 1 b
B) 2 a, 2 b
C) 2 a
D) 2 a, 2 g
E) 1 a, 1 g

Question 5

This region regulates the switching of the b-like globin chains during development.

A) Locus control region
B) Master globin regulator
C) Imprinting control region
D) Globin switch
E) Immediate early region