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Multiple Choice
Which of the following explains why hemoglobin in RBCs binds to O 2 in the lungs but releases O2 in muscle tissues? (Select all that apply).
A
pH is lower in the lungs than in the tissues.
B
pCO2 is lower in the lungs than in the tissues.
C
BPG is produced at higher levels in tissues compared to the lungs.
D
The temperature of the lungs is generally higher than the temperature in actively contracting muscle tissues.
E
None of the above are true.
Verified step by step guidance
1
Understand the role of hemoglobin: Hemoglobin is a protein in red blood cells (RBCs) responsible for transporting oxygen (O2) from the lungs to tissues and returning carbon dioxide (CO2) from tissues to the lungs.
Consider the effect of pCO2: The partial pressure of CO2 (pCO2) is lower in the lungs than in the tissues. This difference affects hemoglobin's affinity for oxygen, as higher pCO2 in tissues promotes oxygen release due to the Bohr effect.
Examine the role of BPG: 2,3-Bisphosphoglycerate (BPG) is produced at higher levels in tissues compared to the lungs. BPG binds to hemoglobin and decreases its affinity for oxygen, facilitating oxygen release in tissues.
Analyze temperature effects: The temperature in actively contracting muscle tissues is generally higher than in the lungs. Increased temperature can reduce hemoglobin's affinity for oxygen, promoting oxygen release in tissues.
Evaluate pH differences: The pH is actually higher in the lungs than in the tissues, not lower. This higher pH in the lungs increases hemoglobin's affinity for oxygen, aiding in oxygen binding.