Which of the following statement correctly defines "Bohr effects"

Options

A. (a) rise in `P_(CO2)` with a decrease in pH
B. (b) rise in `P_(CO2)` with a decrease in `CO_(2)` concentration
C. (c) rise in `P_(CO2)` with an increase in `CO_(2)` concentration
D. (d) rise in `P_(CO2)` with an increase in `P_(CO_(2))` and decrease in `P_(O_(2))`

Answer

To define the "Bohr effect," we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Bohr Effect**: The Bohr effect refers to the physiological phenomenon where the oxygen binding affinity of hemoglobin is influenced by the concentration of carbon dioxide (CO2) and the pH level in the environment.

2. **Effect of CO2 on Oxygen Binding**: As the concentration of CO2 increases, the pH of the blood decreases (becomes more acidic). This decrease in pH leads to a reduction in the oxygen binding capacity of hemoglobin, meaning that hemoglobin releases oxygen more readily.

3. **Effect of pH on Oxygen Binding**: Conversely, in environments where the pH is higher (more basic), the binding capacity of hemoglobin for oxygen increases, allowing hemoglobin to hold onto oxygen more effectively.

4. **Conclusion**: Therefore, the Bohr effect indicates that there is an inverse relationship between CO2 concentration and pH with respect to hemoglobin's affinity for oxygen. Specifically, increased CO2 concentration (which lowers pH) enhances oxygen offloading, while decreased CO2 concentration (which raises pH) enhances oxygen loading.

5. **Identifying the Correct Statement**: Among the provided options, the statement that correctly defines the Bohr effect is: "rise in pCO2 with decrease in pH." This aligns with the understanding that increased CO2 leads to a decrease in pH, which in turn affects hemoglobin's ability to bind oxygen.

### Final Answer:
The statement that correctly defines the "Bohr effect" is: **"rise in pCO2 with decrease in pH."**

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