The globin chains making up Hb A are: a. Two e and two g ...

[mspears3]

The globin chains making up Hb A are:
 
  a. Two e and two g chains
  b. Two V and two e chains
  c. Two a and two g chains
  d. Two a and two b chains

Question 2

Which of the following provides a negative feedback for heme synthesis, thus helping to control, by decreasing, its synthesis?
 
  a. Concentration of heme in the developing RBC
  b. Concentration of hemoglobin in blood
  c. Concentration of globin chain in the developing RBC
  d. Number of RBCs in circulation

[frogdreck123456]

Answer to Question 1

ANS: D
Hb A is composed of two a and two g chains; V and e chains are embryonic chains and are seen only in fetal life. Hb F is composed of two a and two g chains.

Answer to Question 2

ANS: A
As the concentration of heme increases in the developing RBC, it acts as a negative feedback to decrease further synthesis of heme. This helps control its rate of production.