Author Question: Which of the following correctly describes the structure of normal hemoglobin A (Hb A)? a. Four ... (Read 49 times)

WWatsford · **on:** Jun 25, 2018

Which of the following correctly describes the structure of normal hemoglobin A (Hb A)?

a. Four identical polypeptide chains, each containing two heme groups
b. Two a and two b polypeptide chains, each containing one heme group
c. Conjugated protein with 141 amino acids, containing two atoms of iron
d. Two d and two g polypeptide chains, each containing a single heme group

Question 2

Which of the following is most responsible for the strength and pliancy of the red cell membrane?

a. Glycophorin A
b. Spectrin
c. Cholesterol
d. Ankyrin

johnpizzaz · **Reply #1 on:** Jun 25, 2018

Answer to Question 1

ANS: B
Hb A is composed of two a and two b chains. Each of these chains contains one heme group.

Answer to Question 2

ANS: B
Spectrin composes 50 to 70 of the membrane skeletal mass and is the primary peripheral protein involved in maintaining the skeletal structure of the red cell. By the way it lines up with other spectrin molecules, it also plays an important role in making the red cell membrane deformable (pliant). This flexibility is important for permitting the red cell to squeeze through pores that have a diameter smaller than that of the red cell.