3.The Red Blood Cell: Structure and Function

Question 1

1. Which of the following is not a crucial area of RBC sur-vival and function?
   a.Integrity of RBC cellular membrane
   b.Cell metabolism
   c.Intravascular hemolysis
   d. Hemoglobin structure

Answer 1

c.Intravascular hemolysis

Question 2

2.Which abnormal RBC is not caused by a structural membrane defect?
a.Spherocyte
b.Target cell
c.Siderocyte
d.Acanthocyte

Answer 2

c.Siderocyte

Question 3

3. Which list represents the complete set of processes nec-essary for normal hemoglobin production?

a. Iron delivery and supply, synthesis of protoporphyrins,and globin synthesis
b.Iron salvage, synthesis of conjugated bilirubin, and haptoglobin synthesis
c. Iron accumulation, synthesis of hemopexin, and glo-bin catabolism
d. Iron catabolism, synthesis of uroporphyrinogen,and ferritin synthesis

Answer 3

a. Iron delivery and supply, synthesis of protoporphyrins,and globin synthesis

Question 4

4. What is the correct list for the number and type of globin chains in normal adult hemoglobin?
   a. Four α, two β and two δ chains
   b. Two α and two non-α chains
   c. Two α, four β, one δ, and one e chain
   d. Two α, two β, two δ, and one e chain

Answer 4

b. Two α and two non-α chains

Question 5

5.What is the composition of normal adult hemoglobin?
a. 92% to 95% HbA; 5% to 8% HbA2; 1% to 2% HbF
b. 90% to 92% HbA; 2% to 3% HbA2; 2% to 5% HbF
c. 80% to 85% HbA; 2% to 3% HbA2; 1% to 2% HbF
d. 95% to 97% HbA; 2% to 3% HbA2; 1% to 2% HbF

Answer 5

d. 95% to 97% HbA; 2% to 3% HbA2; 1% to 2% HbF

Question 6

6.Which of the following cells is caused by iron accu-mulation?
a.Acanthocyte
b.Ringed sideroblast
c.Burr cell
d.Bite cell

Answer 6

b.Ringed sideroblast

Question 7

7.Which of the following is a complete list of abnormal he-moglobins that are unable to transport or deliver oxygen?

a.Carboxyhemoglobin and methemoglobin
b.Methemoglobin and fetal hemoglobin
c.Carboxyhemoglobin,sulfhemoglobin,and fetal hemoglobin
d.Carboxyhemoglobin,methemoglobin,and sulfhemoglobin

Answer 7

d.Carboxyhemoglobin,methemoglobin,and sulfhemoglobin

Question 8

8.Which metabolic pathway generates 90% of the ATP needed by RBCs?

a.Methemoglobin reductase pathway
b.Hexose monophosphate shunt
c.Embden-Meyerhof pathway
d.Leubering-Rapaport shunt

Answer 8

c.Embden-Meyerhof pathway

Question 9

9.What steps occur in the extravascular breakdown of senescent RBCs?

a. RES cells phagocytize red cells; iron is coupled to trans-ferrin and returned to marrow; globin is returned to amino acid pool; biliverdin is converted to bilirubin; bilirubin is coupled to albumin and transported to liver, bilirubin glu-curonide is converted to urobilinogen and excreted.

b.RBCs break down in lumen of vessel; the haptoglobin-hemoglobin complex goes to the liver;unbound hemoglobin dimers are excreted through the kidney as hemosiderin, hemoglobin, or methemoglobin; hapto-globin is broken down to be excreted as urobilinogen

c. RES cells phagocytize red cells; iron is coupled to transferrin and returned to marrow; globin is returned to amino acid pool; the haptoglobin-hemoglobin com-plex goes to liver; unbound hemoglobin dimers are excreted through kidney as hemosiderin,hemoglobin,or methemoglobin; haptoglobin is broken down to be excreted as urobilinogen.

d.RBCs break down in lumen of vessel; haptoglobin picks up dissociated hemoglobin; the haptoglobin-hemoglobin complex goes to the liver; biliverdin is converted to bilirubin; bilirubin is coupled to albumin and transported to liver; bilirubin glucuronide is converted to urobilinogen and excreted.

Answer 9

a. RES cells phagocytize red cells; iron is coupled to trans-ferrin and returned to marrow; globin is returned to amino acid pool; biliverdin is converted to bilirubin; bilirubin is coupled to albumin and transported to liver, bilirubin glu-curonide is converted to urobilinogen and excreted.

Question 10

10. What steps occur in the intravascular breakdown of senescent RBCs?

a. RES cells phagocytize red cells; iron is coupled to trans-ferrin and returned to marrow; globin is returned to amino acid pool; biliverdin is converted to bilirubin; bilirubin is coupled to albumin and transported to liver, bilirubin glu-curonide is converted to urobilinogen and excreted.

b.RBCs break down in lumen of vessel; the haptoglobin-hemoglobin complex goes to the liver;unbound hemoglobin dimers are excreted through the kidney as hemosiderin, hemoglobin, or methemoglobin; hapto-globin is broken down to be excreted as urobilinogen

c. RES cells phagocytize red cells; iron is coupled to transferrin and returned to marrow; globin is returned to amino acid pool; the haptoglobin-hemoglobin com-plex goes to liver; unbound hemoglobin dimers are excreted through kidney as hemosiderin,hemoglobin,or methemoglobin; haptoglobin is broken down to be excreted as urobilinogen.

d.RBCs break down in lumen of vessel; haptoglobin picks up dissociated hemoglobin; the haptoglobin-hemoglobin complex goes to the liver; biliverdin is converted to bilirubin; bilirubin is coupled to albumin and transported to liver; bilirubin glucuronide is converted to urobilinogen and excreted.

Answer 10

b.RBCs break down in lumen of vessel; the haptoglobin-hemoglobin complex goes to the liver;unbound hemoglobin dimers are excreted through the kidney as hemosiderin, hemoglobin, or methemoglobin; hapto-globin is broken down to be excreted as urobilinogen