Which of the following statement is TRUE about Bohr’s effect?
**Core Concept**
The Bohr effect describes the relationship between oxygen binding to hemoglobin in red blood cells and the pH of the blood. It is a critical concept in understanding how the body adapts to changes in oxygen delivery and acid-base balance.
**Why the Correct Answer is Right**
The Bohr effect states that as the pH of the blood decreases (becoming more acidic), the affinity of hemoglobin for oxygen decreases, allowing more oxygen to be released to tissues. This is due to the binding of hydrogen ions (H+) to the hemoglobin molecule, which shifts the oxygen-hemoglobin dissociation curve to the right. This mechanism allows the body to adapt to conditions of low oxygen levels (hypoxia) by increasing oxygen delivery to tissues.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately describe the Bohr effect. The Bohr effect is a specific physiological response to changes in pH, not a general characteristic of oxygen binding to hemoglobin.
**Option B:** This option is incorrect because it is a description of the opposite phenomenon - the Haldane effect, which describes how carbon dioxide binding to hemoglobin affects oxygen binding.
**Option C:** This option is incorrect because it is a description of the oxygen-hemoglobin dissociation curve, but does not specifically address the Bohr effect.
**Clinical Pearl / High-Yield Fact**
The Bohr effect is a critical adaptation that allows the body to increase oxygen delivery to tissues during conditions of hypoxia or acidosis. This is why patients with conditions such as chronic obstructive pulmonary disease (COPD) or severe anemia may exhibit increased respiratory drive and metabolic alkalosis.
**Correct Answer:** C. The oxygen-hemoglobin dissociation curve shifts to the right at low pH, allowing more oxygen to be released to tissues.