Question
Which of the following factors causes a rightward shift in the oxygen-hemoglobin dissociation curve?
| A. |
Increase in CO₂
|
| B. |
Increase in O₂
|
| C. |
Decrease in CO₂
|
| D. |
Decrease in temperature
|
Show Answer
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Correct Answer � A
Explanation
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|
Rightward Shift in Oxygen-Hemoglobin Dissociation Curve
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A rightward shift in the oxygen-hemoglobin dissociation curve means reduced affinity of hemoglobin for oxygen, promoting oxygen unloading to tissues.
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This shift is beneficial during conditions where tissues demand more oxygen, such as exercise or hypoxia.
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Increased CO₂ levels cause a rightward shift due to the Bohr Effect.
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CO₂ enters red blood cells, forms carbonic acid (H₂CO₃), which dissociates into H⁺ and HCO₃⁻.
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The increased H⁺ concentration lowers pH, promoting oxygen release from hemoglobin.
Why Other Options Are Incorrect:
B. Increase in O₂
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Leads to more oxygen binding, not release.
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Causes a leftward shift, as in lungs where oxygen uptake is favored.
C. Decrease in CO₂
D. Decrease in temperature
