What will be the effect on the oxygen dissociation curve, if the temperature is decreased ?

Options

A. The curve will be shifted right
B. The curve will be shifted left
C. The curve will became a straight line
D. It is unpredictable

Answer

To solve the question regarding the effect of decreased temperature on the oxygen dissociation curve, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Oxygen Dissociation Curve**:
- The oxygen dissociation curve illustrates the relationship between the partial pressure of oxygen (pO2) and the percentage saturation of hemoglobin with oxygen. It typically has a sigmoid shape.

2. **Factors Affecting Hemoglobin-Oxygen Binding**:
- Several factors can influence the binding of oxygen to hemoglobin, including:
- Partial pressure of oxygen (pO2)
- Partial pressure of carbon dioxide (pCO2)
- Concentration of hydrogen ions (H+ ions, which affects pH)
- Temperature

3. **Effect of Temperature on Oxygen Binding**:
- When temperature increases, it generally decreases the affinity of hemoglobin for oxygen, leading to a rightward shift in the curve. Conversely, when temperature decreases, the affinity of hemoglobin for oxygen increases, which shifts the curve to the left.

4. **Analyzing the Question**:
- The question specifically asks about the effect of decreasing temperature. Since lower temperatures favor the binding of oxygen to hemoglobin, we can conclude that the curve will shift to the left.

5. **Conclusion**:
- Therefore, the correct answer to the question is that the oxygen dissociation curve will shift to the left when the temperature is decreased.

### Final Answer:
**B. The curve will be shifted left.**

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