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 oxyhaemogolbin

Answer

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

**Step 1: Analyze Statement A**
- Statement A: "Low temperature favors dissociation of oxygen from oxyhemoglobin."
- According to the Bohr effect, low temperature actually causes a left shift in the oxygen dissociation curve. This means that hemoglobin holds onto oxygen more tightly at lower temperatures, making it less likely to dissociate. Therefore, this statement is incorrect.

**Step 2: Analyze Statement B**
- Statement B: "A rise in pCO2 of blood decreases O2 affinity of hemoglobin."
- This statement is correct. An increase in the partial pressure of carbon dioxide (pCO2) in the blood leads to a decrease in the affinity of hemoglobin for oxygen. This is a key aspect of the Bohr effect, where increased CO2 levels promote oxygen release from hemoglobin.

**Step 3: Analyze Statement C**
- Statement C: "Low pCO2 at alveoli favors the formation of hemoglobin."
- This statement is also correct. In the alveoli, where pCO2 is low, hemoglobin has a higher affinity for oxygen, promoting the binding of oxygen to hemoglobin.

**Step 4: Analyze Statement D**
- Statement D: "High pH, high H+ concentration in blood causes dissociation of oxygen from hemoglobin."
- This statement is correct. High H+ concentration (which corresponds to low pH) leads to the dissociation of oxygen from hemoglobin. This is consistent with the Bohr effect, where increased acidity promotes oxygen release.

**Conclusion: Identify the Incorrect Statement**
- After analyzing all statements, we find that Statement A is the only incorrect statement according to the Bohr effect.

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

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