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

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 determine the effect on the oxygen dissociation curve when the temperature is decreased, we can analyze the relationship between temperature, hemoglobin, and oxygen affinity step-by-step.

### Step-by-Step Solution:

1. **Understanding the Oxygen Dissociation Curve**:
- The oxygen dissociation curve illustrates how readily hemoglobin binds to oxygen at different partial pressures of oxygen (pO2).
- The x-axis represents the partial pressure of oxygen, while the y-axis represents the saturation of hemoglobin with oxygen (oxyhemoglobin concentration).

2. **Effect of Temperature on Hemoglobin**:
- Hemoglobin's affinity for oxygen is influenced by various factors, including temperature.
- When the temperature decreases, hemoglobin's affinity for oxygen increases. This means that hemoglobin holds onto oxygen more tightly.

3. **Consequences of Increased Affinity**:
- With a higher affinity for oxygen, hemoglobin will bind more oxygen and form more oxyhemoglobin.
- As a result, there will be a lower tendency for oxygen to dissociate from hemoglobin.

4. **Shifting the Curve**:
- Because of the increased binding and reduced dissociation, the oxygen dissociation curve will shift to the left.
- This leftward shift indicates that at any given partial pressure of oxygen, hemoglobin is more saturated with oxygen compared to normal conditions.

5. **Conclusion**:
- Therefore, if the temperature is decreased, the oxygen dissociation curve will shift to the left, indicating an increased affinity of hemoglobin for oxygen.

### Final Answer:
(b) The curve will be shifted left.

---