Which of the following has no effect on the oxyhemoglobin dissociation curve?

• A. Blood pH
• B. Partial pressure of carbon dioxide (\(P_{CO_2}\))
• C. Temperature
• D. Glucose concentration in plasma

Answer: (D)

Verified step by step guidance

1. Understand the oxyhemoglobin dissociation curve: This curve represents the relationship between the partial pressure of oxygen (\(P_{O_2}\)) and the percentage of hemoglobin saturated with oxygen. Factors that affect this curve include blood pH, partial pressure of carbon dioxide (\(P_{CO_2}\)), and temperature, as they influence hemoglobin's affinity for oxygen.
2. Review the Bohr effect: The Bohr effect explains how changes in blood pH and \(P_{CO_2}\) affect hemoglobin's oxygen-binding affinity. A decrease in pH (more acidic conditions) or an increase in \(P_{CO_2}\) shifts the curve to the right, reducing hemoglobin's affinity for oxygen.
3. Consider the role of temperature: Higher temperatures reduce hemoglobin's affinity for oxygen, causing a rightward shift in the curve. Conversely, lower temperatures increase oxygen affinity, shifting the curve to the left.
4. Evaluate glucose concentration in plasma: Glucose concentration does not directly affect hemoglobin's oxygen-binding properties or the oxyhemoglobin dissociation curve. It is not involved in the physiological mechanisms that alter hemoglobin's affinity for oxygen.
5. Conclude that glucose concentration in plasma has no effect on the oxyhemoglobin dissociation curve, as it does not influence the factors (pH, \(P_{CO_2}\), and temperature) that modify hemoglobin's oxygen-binding affinity.