which of the following is not correct according to Bohr's effect?

Options

A. low temperature favours the dissociation of oxygen from oxyhaemoglobin
B. a rise in `pCO_2` of blood decreases oxygen affinity of haemoglobin
C. low `pCO_2` at alveoli favour the formation of oxyheamogolbin
D. high `H^+` concentration in blood causes dissociation of oxyhaemoglobin

Answer

To determine which statement is not correct according to Bohr's effect, we will analyze the provided options step by step.

### Step 1: Understand Bohr's Effect
Bohr's effect describes how the affinity of hemoglobin for oxygen decreases in response to increased levels of carbon dioxide (PCO2) and decreased pH (increased H+ concentration). This effect facilitates oxygen release in tissues where it is needed most, such as during high metabolic activity.

### Step 2: Analyze Each Statement
1. **Low temperature favors the dissociation of oxygen from hemoglobin.**
- Low temperature generally decreases metabolic activity. According to Bohr's effect, lower temperatures would favor the association of hemoglobin with oxygen, not dissociation. Therefore, this statement is incorrect.

2. **Rise in PCO2 of the blood decreases the oxygen affinity of hemoglobin.**
- This statement aligns with Bohr's effect. An increase in PCO2 leads to a decrease in pH, which in turn decreases hemoglobin's affinity for oxygen, facilitating oxygen release. This statement is correct.

3. **Low PCO2 at the alveoli favors the formation of oxyhemoglobin.**
- At the alveoli, where oxygen is being taken up, the PCO2 is low. This low PCO2 promotes the binding of oxygen to hemoglobin, thus favoring the formation of oxyhemoglobin. This statement is correct.

4. **High H+ ion concentration in the blood causes dissociation of oxyhemoglobin.**
- High H+ concentration indicates a lower pH, which is associated with increased metabolic activity. This condition promotes the release of oxygen from hemoglobin, making this statement correct.

### Step 3: Conclusion
Based on the analysis:
- The first statement, "Low temperature favors the dissociation of oxygen from hemoglobin," is not correct according to Bohr's effect. Therefore, it is the answer to the question.

### Final Answer
The statement that is not correct according to Bohr's effect is: **Low temperature favors the dissociation of oxygen from hemoglobin.**

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