CHAPTER 9: 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 Na+, K+, and Ca++. 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 +3 valence state by several pathological mechanisms. What portion of the Embden-Meyerhof pathway reduces iron to the physiologic +2 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