Question

Which of the following condition(s) lead(s) to reduced affinity of O₂ for human hemoglobin?

• A. Reduction of pH of blood plasma from pH 7.4 to 7.2
• B. Decrease of partial pressure of CO₂ in the lungs from 6 to 2 kPa
• C. Enhancement of intracellular 2, 3-bis phosphoglycerate (BPG) level from 5 to 8 mM
• D. Increase in ambient CO level from 1 to 600 ppm

Hint:

The Bohr effect describes how decreased pH and increased BPG levels decrease hemoglobin's affinity for oxygen, aiding oxygen release in tissues.

Answer 1

The Correct Option is A, C

Step 1: Understanding the factors that affect hemoglobin affinity for O₂.
The affinity of hemoglobin for oxygen is influenced by various factors including pH, partial pressure of CO₂, levels of 2,3-bisphosphoglycerate (BPG), and ambient CO₂ levels.

Step 2: Analyzing the options.
- (A) Correct: A decrease in pH, or acidosis, reduces the affinity of hemoglobin for oxygen, known as the Bohr effect. This facilitates the release of oxygen to tissues.
- (B) Incorrect: Decrease in partial pressure of CO₂ increases the affinity of hemoglobin for oxygen, making it less likely to release O₂.
- (C) Correct: Higher levels of 2,3-bisphosphoglycerate (BPG) decrease the affinity of hemoglobin for O₂, promoting oxygen release to tissues.
- (D) Incorrect: While an increase in ambient CO₂ levels affects the respiratory system, it does not directly reduce the affinity of hemoglobin for oxygen in this context.

Final Answer:
\[ \boxed{\text{(A) and (C) are correct.}} \]