Erythrocyte Metabolism and Membrane Structure and Function

Question 1

1. Which RBC process does not require energy?
   a. Oxygen transport
   b. Cytoskeletal protein deformability
   c. Preventing the peroxidation of proteins and lipids
   d. Maintaining cytoplasm cationic electrochemical gradients

Answer 1

a. Oxygen transport

Question 2

2. What pathway anaerobically generates energy in the form of
   ATP?
   a. Hexose monophosphate pathway
   b. Rapoport-Luebering pathway
   c. Embden-Meyerhof pathway
   d. 2,3-BPG pathway

Answer 2

c. Embden-Meyerhof pathway

Question 3

3. Which is true concerning 2,3-BPG?
   a. The least abundant of RBC organophosphates
   b. Enhances O2 release from hemoglobin
   c. Source of RBC glucose
   d. Source of RBC ATP

Answer 3

b. Enhances O2 release from hemoglobin

Question 4

4. To survive, the RBC must detoxify peroxides. What
   hexose-monophosphate shunt product(s) accomplishes
   detoxification?
   a. ATP
   b. 2,3-BPG
   c. Pyruvic and lactic acid
   d. NADPH and reduced glutathione

Answer 4

d. NADPH and reduced glutathione

Question 5

5. Which of the following helps maintain RBC shape?
   a. Membrane phospholipids
   b. Cytoskeletal proteins
   c. GPI anchor
   d. Glycocalyx

Answer 5

b. Cytoskeletal proteins

Question 6

6. The glycolipids of the RBC membrane:
   a. Provide flexibility.
   b. Carry RBC antigens.
   c. Constitute ion channels.
   d. Attach the cytoskeleton to the lipid layer.

Answer 6

b. Carry RBC antigens.

Question 7

7. RBC membranes block passage of most large molecules
   such as proteins, but allow passage of small molecules
   such as the cations Na1, K1, and Ca11. What is the term
   for this membrane property?
   a. Semipermeable
   b. Deformable
   c. Intangible
   d. Flexible

Answer 7

a. Semipermeable

Question 8

8. RBC membrane phospholipids are arranged:
   a. In a hexagonal lattice.
   b. In chains beneath a protein exoskeleton.
   c. In two layers whose composition is asymmetric.
   d. So that hydrophobic portions are facing the plasma.

Answer 8

c. In two layers whose composition is asymmetric.

Question 9

9. RBC membrane cholesterol is replenished from the:
   a. Plasma.
   b. Mitochondria.
   c. Cytoplasm.
   d. EMB pathway

Answer 9

a. Plasma.

Question 10

10. The hemoglobin iron ion may become oxidized to the 13
    valence state by several pathological mechanisms. What
    portion of the Embden-Meyerhof pathway reduces iron to
    the physiologic 12 valence state?
    a. Methemoglobin reductase pathway
    b. Hexose monophosphate pathway
    c. Rapoport-Luebering pathway
    d. The 2,3-BPG shunt

Answer 10

a. Methemoglobin reductase pathway

Question 11

11. Which of the following is an example of a transmembrane
    or integral membrane protein?
    a. Glycophorin A
    b. Ankyrin
    c. Spectrin
    d. Actin

Answer 11

a. Glycophorin A

Question 12

12. Abnormalities in the horizontal and vertical linkages
    of the transmembrane and cytoskeletal RBC membrane
    proteins may be seen as:
    a. Shape changes.
    b. Methemoglobin increase.
    c. Reduced hemoglobin content.
    d. Enzyme pathway deficiencies

Answer 12

a. Shape changes.